Abstract:
Topical formulations of olopatadine for treatment of allergic or inflammatory disorders of the nose are disclosed. The aqueous formulations contain approximately 0.6% (w/v) of olopatadine.

Description:
[0001]    This application is a continuation-in-part of Ser. No. 11/079,996, filed Mar. 15, 2005, which is a continuation of Ser. No. 10/175,106, filed Jun. 19, 2002, which claims priority to U.S. Provisional Application Ser. No. 60/301,315, filed Jun. 27, 2001, all of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to topical formulations used for treating allergic and inflammatory diseases. More particularly, the present invention relates to formulations of olopatadine and their use for treating and/or preventing allergic or inflammatory disorders of the nose. 
         [0004]    2. Description of the Related Art 
         [0005]    As taught in U.S. Pat. Nos. 4,871,865 and 4,923,892, both assigned to Burroughs Wellcome Co. (“the Burroughs Wellcome Patents”), certain carboxylic acid derivatives of doxepin, including olopatadine (chemical name: Z-11-(3-dimethylaminopropylidene)-6,11-dihydrodibenz[b,e]oxepine-2-acetic acid), have antihistamine and antiasthmatic activity. These two patents classify the carboxylic acid derivatives of doxepin as mast cell stabilizers with antihistaminic action because they are believed to inhibit the release of autacoids (i.e., histamine, serotonin, and the like) from mast cells and to inhibit directly histamine&#39;s effects on target tissues. The Burroughs Wellcome Patents teach various pharmaceutical formulations containing the carboxylic acid derivatives of doxepin, including nasal spray and ophthalmic formulations. See, for example, Col. 7, lines 7-26, and Examples 8 (H) and 8 (I) of the &#39;865 patent. 
         [0006]    U.S. Pat. No. 5,116,863, assigned to Kyowa Hakko Kogyo Co., Ltd., (“the Kyowa patent”), teaches that acetic acid derivatives of doxepin and, in particular, olopatadine, have anti-allergic and anti-inflammatory activity. Olopatadine is the cis form of the compound having the formula: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0000]    Medicament forms taught by the Kyowa patent for the acetic acid derivatives of doxepin include a wide range of acceptable carriers; however, only oral and injection administration forms are mentioned. 
         [0007]    U.S. Pat. No. 5,641,805, assigned to Alcon Laboratories, Inc. and Kyowa Hakko Kogyo Co., Ltd., teaches topical ophthalmic formulations containing olopatadine for treating allergic eye diseases. According to the &#39;805 patent, the topical formulations may be solutions, suspensions or gels. The formulations contain olopatadine, an isotonic agent, and “if required, a preservative, a buffering agent, a stabilizer, a viscous vehicle and the like.” See Col. 6, lines 30-43. “[P]olyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid or the like” are mentioned as the viscous vehicle. See Col. 6, lines 55-57. 
         [0008]    PATANOL® (olopatadine hydrochloride ophthalmic solution) 0.1% is currently the only commercially available olopatadine product for ophthalmic use. According to its labelling information, it contains olopatadine hydrochloride equivalent to 0.1% olopatadine, 0.01% benzalkonium chloride, and unspecified amounts of sodium chloride, dibasic sodium phosphate, hydrochloric acid and/or sodium hydroxide (to adjust pH) and purified water. 
         [0009]    Topical olopatadine formulations that are effective as products for treating allergic or inflammatory conditions in the nose are desirable. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides topical olopatadine formulations that are effective as products for treating allergic or inflammatory disorders of the nose. The formulations of the present invention are aqueous solutions that comprise approximately 0.6% olopatadine. Despite their relatively high concentration of olopatadine, they do not contain any polymeric ingredient as a physical stability enhancing ingredient. The formulations contain a phosphate salt that permits the pH of the formulations to be maintained within the range 3.5-3.95 and that also aids in solubilizing the olopatadine drug in the presence of sodium chloride. 
         [0011]    Among other factors, the present invention is based on the finding that stable, nasal spray, solution formulations of olopatadine can be prepared within a pH range of 3.5-3.95 using a phosphate buffer without the need for any polymeric ingredient to enhance the solubility or physical stability of the formulation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIGS. 1A and 1B  show the pH-solubility profile of olopatadine. 
           [0013]      FIG. 2  shows the effect of NaCl and Na 2 HPO 4  on the dissolution of olopatadine in water. 
           [0014]      FIG. 3  shows the effect of NaCl and Na 2 HPO 4  on the dissolution of olopatadine in a nasal vehicle. 
           [0015]      FIG. 4  shows the effect of NaCl and Na 2 HPO 4  concentrations on the dissolution rate of olopatadine in a nasal vehicle. 
           [0016]      FIG. 5  shows the buffer capacity of an olopatadine nasal spray composition. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Unless indicated otherwise, all component amounts are presented on a % (w/v) basis and all references to amounts of olopatadine are to olopatadine free base. 
         [0018]    Olopatadine is a known compound that can be obtained by the methods disclosed in U.S. Pat. No. 5,116,863, the entire contents of which are hereby incorporated by reference in the present specification. The solution formulations of the present invention contain 0.54-0.62% olopatadine. Preferably, the solution formulations contain 0.6% olopatadine. 
         [0019]    Olopatadine has both a carboxylic functional group (pKa 1 =4.18) and a tertiary amino group (pKa 2 =9.79). It exists in different ionic forms depending upon the pH of the solution. Olopatadine exists predominantly as a zwitterion in the pH range between the two pKa values with a negatively-charged carboxylic group and a positively-charged tertiary amino group. The iso-electric point of the olopatadine zwitterion is at pH 6.99. At a pH lower than pKa 1 , cationic olopatadine (with ionized tertiary amino group) is dominant. At a pH higher than pKa 2 , anionic olopatadine (with ionized carboxylic group) is dominant. 
       Acid-Base Equilibrium of Olopatadine 
       [0020]    
       
                 
         
             
             
         
       
     
         [0021]    In many zwitterionic molecules, such as various amino acids, intra-molecular ionic interactions are not significant or do not exist. But the structure of olopatadine is such that intra-molecular interactions exist and are significant, possibly due to the distance and bonding angle between the oppositely charged functional groups. This interaction effectively reduces the ionic and dipole character of the molecule. The net effect of the intra-molecular interactions between the oppositely charged functional groups is the reduction of aqueous solubility of olopatadine. Olopatadine has the pH-solubility profile shown in  FIGS. 1A  (theoretical) and  1 B (obtained using phosphate buffer). 
         [0022]    Generally, olopatadine will be added in the form of a pharmaceutically acceptable salt. Examples of the pharmaceutically acceptable salts of olopatadine include inorganic acid salts such as hydrochloride, hydrobromide, sulfate and phosphate; organic acid salts such as acetate, maleate, fumarate, tartrate and citrate; alkali metal salts such as sodium salt and potassium salt; alkaline earth metal salts such as magnesium salt and calcium salt; metal salts such as aluminum salt and zinc salt; and organic amine addition salts such as triethylamine addition salt (also known as tromethamine), morpholine addition salt and piperidine addition salt. The most preferred form of olopatadine for use in the solution compositions of the present invention is the hydrochloride salt of (Z)-11-(3-dimethylaminopropylidene)-6,11-dihydro-dibenz-[b,e]oxepin-2-acetic acid. When olopatadine is added to the compositions of the present invention in this salt form, 0.665% olopatadine hydrochloride is equivalent to 0.6% olopatadine free base. Preferably the compositions of the present invention comprise approximately 0.665% olopatadine hydrochloride. 
         [0023]    In addition to olopatadine, the aqueous solution compositions of the present invention comprise a phosphate salt. The phosphate salt not only helps maintain the pH of the compositions within the targeted pH range of 3.5-3.95 by contributing to the buffer capacity of the compositions, but also helps solubilize olopatadine. Suitable phosphate salts for use in the compositions of the present invention include monobasic sodium phosphate, dibasic sodium phosphate, tribasic sodium phosphate, monobasic potassium phosphate, dibasic potassium phosphate, and tribasic potassium phosphate. The most preferred phosphate salt is dibasic sodium phosphate. The compositions of the present invention comprise an amount of phosphate salt equivalent (on an osmolality contribution basis) to 0.2-0.8%, preferably 0.3-0.7%, and most preferably 0.4-0.6% of dibasic sodium phosphate. In a preferred embodiment, the phosphate salt is dibasic sodium phosphate at a concentration of 0.4-0.6% (w/v). In a most preferred embodiment, the compositions contain 0.5% (w/v) dibasic sodium phosphate. 
         [0024]    Phosphate buffer is commonly used in aqueous pharmaceutical compositions formulated near neutral pH. Phosphate buffer (pKa 1 =2.12, pKa 2 =7.1, pKa 3 =12.67) would not normally be chosen for an aqueous composition with a target pH range of 3.5-3.95 because it has low buffer capacity in that region. Other buffering agents are commonly used in aqueous pharmaceutical compositions, including acetate, citrate and borate buffers, but are not suitable for use in the topical nasal compositions of the present invention. Borate buffers are not suitable because they do not have any significant buffer capacity in the pH range 3.5-3.95. Though acetate and citrate buffers have buffer capacity in this region, they are not preferred because they have the potential to cause irritation to nasal mucosal tissues and undesirable taste and/or smell. 
         [0025]    In addition to olopatadine and phosphate salt, the compositions of the present invention comprise sodium chloride as a tonicity-adjusting agent. The compositions contain sodium chloride in an amount sufficient to cause the final composition to have a nasally acceptable osmolality, preferably 240-350 mOsm/kg. Most preferably, the amount of sodium chloride in the compositions of the present invention is an amount sufficient to cause the compositions to have an osmolality of 260-330 mOsm/kg. In a preferred embodiment, the compositions contain 0.3-0.6% sodium chloride. In a more preferred embodiment, the compositions contain 0.35-0.55% sodium chloride, and in a most preferred embodiment, the compositions contain 0.35-0.45% sodium chloride. 
         [0026]    The compositions of the present invention also contain a pharmaceutically acceptable pH-adjusting agent. Such pH-adjusting agents are known and include, but are not limited to, hydrochloric acid (HCl) and sodium hydroxide (NaOH). The compositions of the present invention preferably contain an amount of pH-adjusting agent sufficient to obtain a composition pH of 3.5-3.95, and more preferably, a pH of 3.6-3.8. 
         [0027]    In one embodiment, the aqueous compositions of the present invention consist essentially of olopatadine, phosphate buffer, sodium chloride, a pH-adjusting agent, and water, and have a pH from 3.5-3.95. These compositions can be manufactured as sterile compositions and packaged in multi-dose, pressurized aerosol containers to avoid microbial contamination. In another embodiment, the aqueous compositions of the present invention contain a preservative and a chelating agent such that the compositions pass United States Pharmacopeia/National Formulary XXX criteria for antimicrobial effectiveness, and more preferably the Pharm. Eur. 5 th  Edition criteria for antimicrobial preservation (Pharm. Eur. B preservative effectiveness standard). Suitable preservatives include p-hydroxybenzoic acid ester, benzalkonium chloride, benzododecinium bromide, and the like. Suitable chelating agents include sodium edetate and the like. The most preferred preservative ingredient for use in the compositions of the present invention is benzalkonium chloride (“BAC”). The amount of benzalkonium chloride is preferably 0.005-0.015%, and more preferably 0.01%. The most preferred chelating agent is edetate disodium (“EDTA”). The amount of edetate disodium in the compositions of the present invention is preferably 0.005-0.015%, and more preferably 0.01%. 
         [0028]    The aqueous solution compositions of the present invention do not contain a polymeric ingredient intended to enhance the solubility of olopatadine or the physical stability of the solution. For example, the compositions of the present invention do not contain polyvinylpyrrolidone, polystyrene sulfonic acid, polyvinyl alcohol, polyvinyl acrylic acid, hydroxypropylmethyl cellulose, sodium carboxymethyl cellulose or xanthan gum. 
         [0029]    The compositions of the present invention are preferably packaged in opaque plastic containers. A preferred container is a high-density polyethylene container equipped with a nasal spray pump. Preferably, the package is designed to provide the spray characteristics described in commonly-assigned, co-pending, U.S. Patent Application Publication No. 2006/0110328, which is incorporated herein by reference. 
         [0030]    The present invention also relates to a method of treating allergic rhinitis comprising topically administering to the nasal cavities a composition containing 0.6% olopatadine, phosphate buffer, sodium chloride, a pH-adjusting agent, and water. The compositions optionally contain one or more preservative ingredients. Preferably, the compositions are administered such that 1200 mcg of olopatadine (e.g., 600/mcg per 100 microliter spray×two sprays) is delivered to each nostril twice per day. 
         [0031]    Certain embodiments of the invention are illustrated in the following examples. 
       Example 1 
     Topically Administrable Nasal Solution 
       [0032]      
         [0000]                                  TABLE 1               Ingredient   Amount (%, w/v)                                Olopatadine Hydrochloride   0.665 a         Benzalkonium Chloride   0.01       Edetate Disodium, Dihydrate   0.01       Sodium Chloride   0.41       Dibasic Sodium Phosphate, Anhydrous   0.5       Hydrochloric Acid and/or Sodium Hydroxide   Adjust to pH 3.7 ± 0.1       Purified Water   qs to 100                 a 0.665% w/v olopatadine hydrochloride (665 mcg/100 microliter spray) is equivalent to 0.6% w/v olopatadine as base (600 mcg/100 microliter spray).            
An exemplary compounding procedure for the nasal composition shown in Table 1 is described as below.
   1. Tare a suitable compounding vessel with magnetic stir bar. Add approximately 80% of the batch weight of purified water.   2. While stirring, add dibasic sodium phosphate (anhydrous), sodium chloride, edetate disodium, benzalkonium chloride and olopatadine HCl.   3. Add equivalent to approximately 0.55 g, 6N hydrochloric acid per 100 ml batch.   4. Allow adequate time between each addition for dissolution of each ingredient   5. Add purified water to approximately 90% of final batch weight.   6. Measure pH and adjust, if necessary, to 3.7 with 6N (and/or 1N) hydrochloric acid and 1N sodium hydroxide.   7. Adjust to final batch weight with purified water (QS).   8. Measure final pH.   9. Filter through 0.2 μm filtration membrane.   
 
       Example 2 
     Effect of NaCl and Phosphate Buffer on Dissolution of Olopatadine Hydrochloride 
       [0042]    The effect of NaCl on the dissolution rate of olopatadine hydrochloride in water was determined. NaCl caused a significant reduction in the rate of dissolution of olopatadine. With addition of Na 2 HPO 4 , however, the dissolution of olopatadine was dramatically improved. The complete dissolution of 0.6% olopatadine solution without Na 2 HPO 4  would take at least several hours assuming that the entire amount of olopatadine would eventually dissolve, but with Na 2 HPO 4  it takes less than one minute. The results are shown in  FIG. 2 . 
       Example 3 
     Effect of NaCl and Na 2 HPO 4  on the Dissolution Olopatadine Hydrochloride in a Nasal Vehicle 
       [0043]    The effect of NaCl, Na2HPO4, and mannitol on the dissolution rate of olopatadine hydrochloride in a nasal formulation containing 0.01% EDTA and 0.01% BAC was determined. The results are shown in  FIG. 3 . The effect of phosphate salt in this vehicle is the same as that shown in water in Example 2. 
       Example 4 
     Effect of NaCl and Na 2 HPO 4  Concentrations on Dissolution 
       [0044]    The effect of NaCl and Na 2 HPO 4  concentrations on the dissolution rate of olopatadine hydrochloride in a nasal formulation containing 0.01% EDTA and 0.01% BAC was determined. The results are shown in  FIG. 4 . The aqueous solubility of olopatadine HCl decreases with increasing concentration of NaCl. However, increasing phosphate buffer correlates with increased aqueous solubility of olopatadine HCl in the presence of NaCl. 
       Example 5 
     Effect of Phosphate Buffer on Olopatadine Nasal Spray Composition 
       [0045]    The two compositions shown in Table 2 below were prepared using the procedure described in Example 1 and visual observations of the compositions clarity were made at different points during the compounding procedure. The results are shown in Table 2. 
         [0000]                                          TABLE 2                   Formulation 2A   Formulation 2B       Component   % w/v   % w/v                                Olopatadine HCl   0.665   0.665       Benzalkonium Chloride   0.01 + 3% xs   0.01 + 3% xs       Disodium EDTA   0.01   0.01       Sodium Chloride   0.37   0.7       Dibasic Sodium Phosphate   0.5   absent       Sodium Hydroxide   pH to 3.7   pH to 3.7       Hydrochloric Acid   pH to 3.7   pH to 3.7       Purified Water   qs 100   qs 100       Batch Size   2000 mL   2000 mL       Osmolality   266   250       Initial pH   6.704   3.189       Final pH   3.699   3.618       Visual Observations:       Upon addition of HCl   Solution appeared clear   Solution appeared cloudy           with a few particles   with many particles               suspended       After overnight stirring   Solution became cloudy   Solution remained cloudy           with many particles   with many particles       Final pH adjustment   Solution began to clear   Solution remained cloudy           during pH adjust down   even after pH adjust down           to 3.7   to 3.6       Add final batch quantity of water   Solution remained clear   Solution was still cloudy       (approximately 10%)       with many particles                    
The results for Formulation A show that it is a clear solution. The results for Formulation B show that despite the pH-solubility profile indicating 0.6% olopatadine should dissolve at pH 3.189, the olopatadine did not go into solution. These results demonstrate that, without phosphate buffer, 0.665% olopatadine hydrochloride did not completely dissolve in water in the presence of 0.7% NaCl at a pH as low as 3.6 using the compounding procedure described in Example 1.
 
       Example 6 
     Effect of Phosphate Buffer Added to Cloudy 0.6% Olopatadine Nasal Spray Composition 
       [0046]    Formulations 3A, 3B, and 3C shown in Table 3 were prepared without phosphate buffer and, despite extensive stirring, the olopatadine HCl was not completely solubilized. A portion of Formulation 3C was removed and phosphate buffer was added to form Formulation 3D. The results, summarized in Table 3, demonstrate that 0.665% olopatadine hydrochloride is not soluble in the tested nasal vehicle without a phosphate salt. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                 Formulation 3A 
                 Formulation 3B 
                 Formulation 3C 
                 Formulation 3D 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Olopatadine HCl 
                 0.665 
                 0.665 
                 0.665 
                 0.665 
               
               
                 Benzalkonium 
                 0.01 + 3% xs 
                 0.01 + 3% xs 
                 0.01 + 3% xs 
                 0.01 + 3% xs 
               
               
                 Chloride 
                   
                   
                   
                   
               
               
                 Disodium EDTA 
                 0.01 
                 0.01 
                 0.01 
                 0.01  
               
               
                 Sodium Chloride 
                 0.33 
                 0.7 
                 0.7 
                 0.7  
               
               
                 Sodium Hydroxide 
                 pH to 3.7 
                 pH to 3.7 
                 pH to 3.7 
                 pH to 3.7 
               
               
                 Hydrochloric Acid 
                 pH to 3.7 
                 pH to 3.7 
                 pH to 3.7 
                 pH to 3.7 
               
               
                 Purified Water 
                 qs 100% 
                 qs 100% 
                 qs 100% 
                 qs 100% 
               
               
                 Batch Size 
                 300 mL 
                 800 mL 
                 2000 mL 
                 100 mL 
               
               
                 Osmolality 
                 137 
                 246 
                 250 
                 — 
               
               
                 Initial pH 
                 3.002 
                 3.176 
                 3.189 
                 6.908 
               
               
                 Final pH 
                 3.002 
                 3.664 
                 3.618 
                 3.7  
               
               
                 Visual 
                   
                   
                   
                   
               
               
                 Observations: 
                   
                   
                   
                   
               
               
                   
                 Upon addition of Olopatadine 
                 Upon addition of Olopatadine 
                 Upon addition of Olopatadine 
                 Used dibasic sodium phosphate 
               
               
                   
                 HCl, solution appeared 
                 HCl, solution appeared 
                 HCl, solution appeared 
                 (0.5%) in attempts to clarify a 
               
               
                   
                 cloudy, batch was qs to 
                 cloudy, batch was qs to 
                 cloudy 
                 portion of the cloudy solution 
               
               
                   
                 100% and still cloudy 
                 90% and pH adjusted, 
                   
                 (Formulation 3C) 
               
               
                   
                   
                 solution still cloudy 
                   
                   
               
               
                   
                 After 2.5 hours of stirring, 
                 After 7 hours of stirring, 
                 After overnight stirring, 
                 Within a minute of stirring, the 
               
               
                   
                 solution began to clear 
                 the solution was still 
                 the solution remained 
                 solution became clear with a few 
               
               
                   
                 but still many particles * 
                 cloudy. 
                 cloudy with many particles * 
                 particles ** in solution (mostly 
               
               
                   
                 in solution 
                   
                   
                 fibrous in appearance) 
               
               
                   
                 After 3.5 hours of stirring, 
                 After 7 days of stirring, 
                 After final qs to 100% and 
                 After qs to 100% (using solution 
               
               
                   
                 solution appeared clear 
                 the solution was still 
                 pH adjust, the solution was 
                 from the original batch), the 
               
               
                   
                 with particles * 
                 cloudy with many particles 
                 still cloudy with many 
                 solution remained clear with a few 
               
               
                   
                   
                   
                 particles * 
                 fibrous particles ** 
               
               
                   
                 After overnight stirring, 
                 The batch was qs to 100% 
                 After approx. 7 hours of 
                   
               
               
                   
                 solution appeared clear 
                 and still cloudy with 
                 stirring, the solution was 
                   
               
               
                   
                 with several particles * 
                 many particles * 
                 cloudy with many particles * 
               
               
                   
               
               
                 * Insoluble drug related 
               
               
                 ** Extraneous fibrous particles 
               
             
          
         
       
     
       Example 7 
     Effect of Compounding Sequence on 0.6% Olopatadine Nasal Spray Composition 
       [0047]    The composition of Example 1 above was prepared using four different sequences for the addition of ingredients. The four sequences are indicated in Table 4 in the “OA” (order of addition) columns. In each case, visual observations relating to the composition&#39;s clarity were recorded. The results are shown in Table 4. In all four cases (Formulations 4A-4D), at the end of the compounding procedure, the solutions were clear. (The solutions contained some extraneous fibrous particles that did not appear to be related to the drug or the formulation excipients and were likely attributable to laboratory equipment and glassware.) 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                   
                 4A 
                 4B 
                 4C 
                 4D 
               
             
          
           
               
                 Component 
                 % w/v 
                 OA a   
                 % w/v 
                 OA a, c   
                 % w/v 
                 OA a   
                 % w/v 
                 OA a   
               
               
                   
               
             
          
           
               
                 Olopatadine HCl 
                 0.665 
                 3 
                 0.665 
                 5 
                 0.665 
                 2 
                 0.665 
                 2 
               
               
                 Benzalkonium Chloride 
                 0.01 
                 4 
                 0.01 
                 4 
                 0.01 
                 3 
                 0.01 
                 4 
               
               
                 Disoditun EDTA 
                 0.01  
                 5 
                 0.01 
                 3 
                 0.01 
                 4 
                 0.01 
                 5 
               
               
                 Sodium Chloride 
                 0.41 
                 6 
                 0.41 
                 2 
                 0.41 
                 5 
                 0.41 
                 6 
               
               
                 Dibasic Sodium Phosphate 
                 0.5 
                 1 
                 0.5 
                 1 
                 0.5 
                 6 
                 0.5 
                 1 
               
               
                 (Anhydrous) 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Sodium Hydroxide 
                 pH to 3.7 
                 NA b   
                 pH to 3.7 
                 NA b   
                 pH to 3.7 
                 NA b   
                 pH to 3.7 
                 NA b   
               
               
                 Hydrochloric Acid 
                 pH to 3.7 
                 2 
                 pH to 3.7 
                 6 
                 pH to 3.7 
                 1 
                 pH to 3.7 
                 3 
               
               
                 Purified Water 
                 qs 100% 
                 NA 
                 qs 100% 
                 NA 
                 qs 100% 
                 NA 
                 qs 100% 
                 NA 
               
             
          
           
               
                 Batch Size 
                 100 mL 
                 100 mL 
                 100 mL 
                 100 mL 
               
               
                 Sodium Hydroxide added 
                 0.238 g (1N) 
                 None 
                 None 
                 None 
               
               
                 Hydrochloric Acid added 
                 0.576 g (6N) 
                 0.550 g (6N) 
                 0.550 g (6N) 
                 0.550 g (6N) 
               
               
                 Initial Observations 
                 Cloudy, many suspended 
                 Cloudy, many suspended 
                 Cloudy, many suspended 
                 Cloudy, many suspended 
               
               
                   
                 particles 
                 particles 
                 particles 
                 particles 
               
               
                 Additional observations 
                 After 10 minutes-solution 
                 After 1 minute-clear with 
                 After 2 minutes-clear with a 
                 After 5 minutes-clear with a 
               
               
                   
                 began to clear, many suspended 
                 several suspended particles 
                 few suspended particles 
                 few suspended particles 
               
               
                   
                 particles 
                   
                   
                   
               
               
                   
                 After 30 minutes-clear with 
                 After 6 minutes-clear with a 
                 After 7 minutes-clear with a 
                 After 20 minutes-clear with 
               
               
                   
                 several suspended particles 
                 a few suspended particles 
                 few suspended particles 
                 few suspended particles 
               
               
                   
                 After 1 hour-clear with many 
                 After 1 hour-clear with a few 
                 After 1 hour-clear with 
                 After 1 hour-clear with 
               
               
                   
                 suspended particles* 
                 suspended particles* 
                 several suspended particles* 
                 several suspended particles* 
               
               
                   
                 Next day (approx 16 hours)- 
                 Next day (approx 16 hours) - 
                 Next day (approx 16  
                 Next day (approx 16  
               
               
                   
                 clear with several particles* 
                 clear with a few particles* 
                 hours)- 
                 hours)- 
               
               
                   
                   
                   
                 clear with a few particles* 
                 clear with a few particles* 
               
               
                 pH 
                 3.698 
                 3.692 
                 3.718 
                 3.724 
               
               
                 Osmolality 
                 274 
                 283 
                 279 
                 280 
               
               
                   
               
               
                   b NA = not applicable 
               
               
                   c Preferred method of manufacturing 
               
               
                 *Extraneous fibrous particles 
               
             
          
         
       
     
       Example 8 
     Effect of Various Buffer Systems 
       [0048]    The composition of Example 1 above was prepared but acetate, borate and citrate buffers, respectively, were substituted in place of the Phosphate buffer. Visual observations regarding the clarity of each of the compositions were recorded and are shown in Table 5. 
         [0000]    
       
         
               
               
               
               
             
               
               
             
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                   
                 5A 
                 5B 
                 5C 
               
             
          
           
               
                 Component 
                 % w/v 
               
               
                   
               
             
          
           
               
                 Olopatadine HCl 
                 0.665 
                 0.665 
                 0.665 
               
               
                 Benzalkonium 
                 0.01 
                 0.01 
                 0.01 
               
               
                 Chloride 
                   
                   
                   
               
               
                 Disodium EDTA 
                 0.01 
                 0.01 
                 0.01 
               
               
                 Sodium Chloride 
                 0.41 
                 0.41 
                 0.41 
               
               
                 Sodium Acetate 
                 0.5 
                 — 
                 — 
               
               
                 Sodium Borate 
                 — 
                 — 
                 0.5 
               
               
                 Sodium Citrate 
                 — 
                 0.5 
                 — 
               
               
                 Sodium Hydroxide 
                 pH to 3.7 
                 pH to 3.7 
                 pH to 3.7 
               
               
                 Hydrochloric Acid a   
                 pH to 3.7 
                 pH to 3.7 
                 pH to 3.7 
               
               
                 Purified Water 
                 qs 100% 
                 qs 100% 
                 qs 100% 
               
             
          
           
               
                 Batch Size 
                 100 
                 mL 
                 100 
                 mL 
                 100 
                 mL 
               
               
                 Sodium Hydroxide 
                 0.332 
                 g (1N) 
                 0.244 
                 g (1N) 
                 0.963 
                 g (1N) 
               
               
                 added 
                   
                   
                   
                   
                   
                   
               
               
                 Hydrochloric Acid 
                 0.550 
                 g (6N) 
                 0.550 
                 g (6N) 
                 0.550 
                 g (6N) 
               
               
                 added 
                   
                   
                   
                   
                   
                   
               
             
          
           
               
                 pH 
                 3.711 
                 3.710 
                 3.716 
               
               
                 Osmolality 
                 257 
                 246 
                 270 
               
               
                 Visual Observations: 
                   
                   
                   
               
               
                 Observations: Initial 
                 Upon addition of 
                 Upon addition of 
                 Upon addition of 
               
               
                   
                 Olopatadine, batch 
                 Olopatadine, batch 
                 Olopatadine, batch 
               
               
                   
                 appeared cloudy but 
                 appeared cloudy but 
                 appeared cloudy but 
               
               
                   
                 began to clear within a 
                 began to clear within 
                 began to clear with in a 
               
               
                   
                 few seconds 
                 one minute 
                 few seconds 
               
               
                 Additional 
                 After 3 minutes of 
                 After 17 minutes of 
                 After 16 minutes of 
               
               
                 observations: 
                 stirring, solution 
                 stirring, solution 
                 stirring, solution 
               
               
                   
                 appeared clear with a 
                 appeared clear with 
                 appeared clear with a 
               
               
                   
                 few extraneous particles 
                 several large flakey 
                 few large flakey 
               
               
                   
                   
                 particles 
                 particles 
               
               
                   
                 After 20 additional 
                 After 20 additional 
                 After 20 additional 
               
               
                   
                 minutes of stirring, 
                 minutes of stirring, 
                 minutes of stirring, 
               
               
                   
                 solution appeared clear 
                 solution appeared clear 
                 solution appeared clear 
               
               
                   
                 with very few 
                 with very few 
                 with very few 
               
               
                   
                 extraneous particles 
                 extraneous particles 
                 extraneous particles 
               
               
                   
                 The pH was adjusted, 
                 The pH was adjusted, 
                 The pH was adjusted, 
               
               
                   
                 solution was brought to 
                 solution was brought to 
                 solution was brought to 
               
               
                   
                 100% of batch weight 
                 100% of batch weight 
                 100% of batch weight 
               
               
                   
                 and remained clear (with 
                 and remained clear (with 
                 and remained clear (with 
               
               
                   
                 very few extraneous 
                 very few extraneous 
                 very few extraneous 
               
               
                   
                 particles) 
                 particles) 
                 particles) 
               
               
                   
               
             
          
         
       
     
       Example 9 
     Effect of Phosphate Buffer, NaCl, and Hot Water 
       [0049]    The compositions shown in Table 6 were prepared to examine (1) the effect of adding phosphate buffer to a composition containing olopatadine hydrochloride, BAC, EDTA, NaOH/HCl, and NaCl, (2) the effect of adding NaCl to a composition containing olopatadine, BAC, EDTA, NaOH/HCl, and (3) the effect of hot water on the dissolution of olopatadine in a composition comprising olopatadine, BAC, EDTA, NaCl and NaOH/HCl. In each case, visual observations concerning the clarity of the composition were recorded. The results are shown in Table 6. 
         [0000]    
       
         
               
               
               
               
               
               
             
           
               
                 TABLE 6 
               
               
                   
               
               
                 Component 
                 6A1 
                 6A2 
                 6B1 
                 6B2 
                 6C* 
               
               
                   
               
             
             
               
                 Olopatadine HCl 
                 0.665 (3)  
                 Same 
                 0.665 (3)  
                 Same 
                 0.665 (4)  
               
               
                 Benzalkonium 
                 0.01 (5) 
                 Same 
                 0.01 (2) 
                 Same 
                 0.01 (3) 
               
               
                 Chloride 
                   
                   
                   
                   
                   
               
               
                 Disodium EDTA 
                 0.01 (4) 
                 Same 
                 0.01 (1) 
                 Same 
                 0.01 (2) 
               
               
                 Sodium Chloride 
                  0.8 (1) 
                 Same 
                 — 
                 Added 0.8% to 
                  0.8 (1) 
               
               
                   
                   
                   
                   
                 existing solution 
                   
               
               
                 Dibasic Sodium 
                 — 
                 Added 0.5% to 
                 — 
                 — 
                 — 
               
               
                 Phosphate 
                   
                 existing solution 
                   
                   
                   
               
               
                 Sodium Hydroxide 
                 2 drops added (2) 
                 Same 
                 — 
                 Same 
                 pH to 3.7 
               
               
                   
                 qs pH to 3.7 (6) 
                   
                   
                   
                   
               
               
                 Purified Water 
                 qs 100% 
                 Same 
                 qs 100% 
                 Same 
                 qs 100% 
               
               
                 Batch Size 
                      50 mL 
                 25 mL 
                      50 mL 
                 25 mL 
                      50 mL 
               
               
                 Initial pH 
                 3.329 
                 — 
                 2.838 
                 — 
                 2.873 
               
               
                 1N NaOH added 
                 0.087 g 
                 — 
                 0.343 g 
                 — 
                 0.318 g 
               
               
                 Final pH 
                 3.667 
                 — 
                 3.730 
                 — 
                 3.714 
               
               
                 Observations: 
                 Upon addition of 
                 25 mL portion of 
                 Upon addition of 
                 25 mL portion of 
                 Upon addition of 
               
               
                   
                 olopatadine HCl, 
                 batch 1 - 
                 olopatadine HCl, 
                 batch 2 - 
                 olopatadine HCl, 
               
               
                   
                 solution appeared 
                 phosphate added and 
                 solution appeared 
                 NaCl added and 
                 the solution 
               
               
                   
                 cloudy with 
                 allowed to stir. 
                 cloudy with 
                 allowed to stir. 
                 appeared cloudy 
               
               
                   
                 many small white 
                 Within 10 minutes, 
                 many small white 
                 After 10 minutes 
                 with many white 
               
               
                   
                 suspended particles 
                 the solution 
                 suspended particles 
                 of stirring, the 
                 suspended particles 
               
               
                   
                   
                 appeared clear 
                   
                 solution remained 
                   
               
               
                   
                   
                   
                   
                 clear 
                   
               
               
                   
                 After addition of 
                 After one day 
                 After 2 minutes of 
                 After one day 
                 After 5 minutes of 
               
               
                   
                 EDTA and BAC, 
                 without stirring, 
                 stirring, the 
                 without stirring, 
                 stirring, the 
               
               
                   
                 the solution 
                 solution appeared 
                 solution began to 
                 solution appeared 
                 solution began to 
               
               
                   
                 appeared the same 
                 clear with a few 
                 clear, still with 
                 clear with 2 small 
                 clear, still with 
               
               
                   
                   
                 extraneous fibers 
                 many white 
                 white flakey 
                 many small white 
               
               
                   
                   
                 (7:30am) 
                 particles 
                 particles and a few 
                 suspended particles 
               
               
                   
                   
                   
                   
                 extraneous fibers 
                   
               
               
                   
                   
                   
                   
                 (7:30am) 
                   
               
               
                   
                 pH was adjusted 
                 Later that day 
                 After 5 additional 
                 Later that day 
                 After 20 minutes of 
               
               
                   
                 to 3.7 and allowed 
                 (2:45 pm) batch was 
                 minutes of stirring, 
                 (2:45 pm) the 
                 stirring, the 
               
               
                   
                 to stir for 30 
                 observed to be clear 
                 the solution was 
                 batch appeared 
                 solution remained 
               
               
                   
                 minutes, appearance 
                 with many crystals 
                 clear 
                 clear with very 
                 clear with many 
               
               
                   
                 was the same 
                 formed at the bottom 
                   
                 few (~3-4) 
                 small white 
               
               
                   
                   
                 of the beaker 
                   
                 small white flakey 
                 suspended particles 
               
               
                   
                   
                   
                   
                 particles and a 
                   
               
               
                   
                   
                   
                   
                 few extraneous fibers 
                   
               
               
                   
                 After one day 
                 Next day (8:00 am), 
                 After pH adjust and qs 
                 Next day (8:00 am) 
                 After 30 additional 
               
               
                   
                 without stirring, 
                 batch remained 
                 to 100%, the batch 
                 the batch remained 
                 minutes of stirring, 
               
               
                   
                 the solution 
                 the same 
                 remained clear 
                 the same 
                 the solution 
               
               
                   
                 appeared clear with 
                   
                   
                   
                 remained the same 
               
               
                   
                 many small white 
                   
                   
                   
                   
               
               
                   
                 particles at the 
                   
                   
                   
                   
               
               
                   
                 bottom of the 
                   
                   
                   
                   
               
               
                   
                 beaker (7:30am) 
                   
                   
                   
                   
               
               
                   
                 Next day (8:00 am), 
                   
                 After one day without 
                   
                 After pH adjust and 
               
               
                   
                 batch remained 
                   
                 stirring, the solution 
                   
                 qs to 100%, the 
               
               
                   
                 the same 
                   
                 remained clear (7:30am) 
                   
                 solution was 
               
               
                   
                   
                   
                   
                   
                 allowed to stir 
               
               
                   
                   
                   
                   
                   
                 and appeared 
               
               
                   
                   
                   
                   
                   
                 the same 
               
               
                   
                   
                   
                 Next day (8:00 am) batch 
                   
                 After one day 
               
               
                   
                   
                   
                 remained the same 
                   
                 without stirring, 
               
               
                   
                   
                   
                   
                   
                 the solution 
               
               
                   
                   
                   
                   
                   
                 appeared clear with 
               
               
                   
                   
                   
                   
                   
                 many small white 
               
               
                   
                   
                   
                   
                   
                 particles settled 
               
               
                   
                   
                   
                   
                   
                 at the bottom of 
               
               
                   
                   
                   
                   
                   
                 the beaker 
               
               
                   
               
               
                 Note: 
               
               
                 Number in parenthesis refers to order of addition of components. 
               
               
                 *Hot purified water (~70° C.) was used. 
               
             
          
         
       
     
       Example 10 
     Buffer Capacity of Phosphate Buffer 
       [0050]    The contribution of phosphate buffer to the buffer capacity of the composition of Example 1 was determined in a classical acid-base titration experiment. The results are shown in  FIG. 5 . The buffer capacity of the composition of Example 1 (without phosphate buffer) was 2.66 from pH 3.5-3.8 and 2.7 from pH 3.5-3.9. The buffer capacity of the composition of Example 1 (i.e., including phosphate buffer) was 2.93 from pH 3.5-3.8 and 3.1 from pH 3.5-3.8. 
       Example 11 
     Stability of Olopatadine Nasal Spray Compositions Lacking Phosphate Buffer 
       [0051]    The compositions (without phosphate buffer) shown below in Table 7A were prepared. Visual observations of the clarity of each composition were recorded as each composition was prepared. The results are shown in Table 7A. 
         [0000]    
       
         
               
               
               
               
             
               
               
             
               
               
               
               
             
           
               
                 TABLE 7A 
               
             
             
               
                   
               
               
                   
                 7A 
                 7B 
                 7C 
               
             
          
           
               
                 Component 
                 % w/v 
               
               
                   
               
             
          
           
               
                 Olopatadine HCl 
                 0.665 (2) 
                 0.665 (4)  
                 0.665 (5)  
               
               
                 Benzalkonium 
                 — 
                 0.01 (3) 
                 0.01 (4) 
               
               
                 Chloride 
                   
                   
                   
               
               
                 Disodium EDTA 
                 — 
                 0.01 (2) 
                 0.01 (3) 
               
               
                 Sodium Chloride 
                  0.8 (3) 
                  0.8 (5) 
                  0.8 (2) 
               
               
                 Sodium Hydroxide 
                 Adjust pH to 3.95 
                 Adjust pH to 3.95 
                 Adjust pH to 3.95 
               
               
                 Hydrochloric Acid 
                 Adjust pH to 3.95 
                 Adjust pH to 3.95 
                 Adjust pH to 3.95 
               
               
                 Purified Water 
                 qs 100% (1) 
                 qs 100% (1) 
                 qs 100% (1) 
               
               
                 Batch Size 
                 200 mL 
                 200 mL 
                 200 mL 
               
               
                 Osmolality 
                 286 
                 286 
                 n/a 
               
               
                 Initial pH 
                 2.898 
                 2.930 
                 3.098 
               
               
                 Final pH 
                 3.947 
                 3.952 
                 3.957 
               
               
                 Observations: 
                 Upon addition of drug, the solution 
                 Upon addition of drug, solution appeared 
                 Upon addition of drug, the solution 
               
               
                   
                 appeared cloudy with many large flakey 
                 cloudy with many large flakey particles; 
                 appeared cloudy with many large flakey 
               
               
                   
                 particles, after approx 20 minutes, the 
                 within approx 25 minutes, solution 
                 particles. After 3 hours of stirring the 
               
               
                   
                 solution appeared clear with very few 
                 appeared clear with very few fibrous/small 
                 solution remained cloudy with many 
               
               
                   
                 fibrous/small white particles (pH 2.845) 
                 white particles (pH 2.880) 
                 suspended particles 
               
               
                   
                 Upon addition of NaCl, solution remained 
                 Upon addition of NaCl, solution remained 
                 After pH adjust and final qs, the solution 
               
               
                   
                 the same (pH 2.898) 
                 the same (pH 2.930) 
                 remained cloudy with many suspended 
               
               
                   
                   
                   
                 particles (while stirring) 
               
               
                   
                 After pH adjust, final qs and several 
                 After pH adjust, final qs and several 
                   
               
               
                   
                 minutes of stirring, the final solution 
                 minutes of stirring, the final solution 
                   
               
               
                   
                 appeared clear with some fibrous 
                 appeared clear with some fibrous 
                   
               
               
                   
                 particles and a few small white 
                 particles and a few small white 
                   
               
               
                   
                 particles 
                 particles 
               
               
                   
               
               
                 Note: 
               
               
                 Numbers in parenthesis next to the components represents the order of addition. 
               
             
          
         
       
     
         [0052]    Each of the compositions was then split. One portion of each was split again into three storage batches (“pre-filtration”) and the other portion was filtered through a 0.2 μM filter and then split into three storage batches (“post-filtration”). One of the storage batches of each set was stored at room temperature (˜22° C.), one in the refrigerator (˜4° C.), and one subjected to freeze-thaw cycling (one day in the freezer (˜−20° C.) and one day at room temperature, except over the weekends). Visual observations of the clarity of each sample of Formulation 7A (lacking BAC and EDTA) were recorded on the indicated days and the results were recorded. The results are shown in Tables 7B (pre-filtration) and 7C (post-filtration). 
         [0000]    
       
         
               
               
             
               
               
               
               
             
           
               
                 TABLE 7B 
               
             
             
               
                   
               
               
                   
                 7A Pre-Filtration 
               
             
          
           
               
                 Observations: 
                 Bottle 1 (at RT) 
                 Bottle 2 (at 4° C.) 
                 Bottle 3 (at FTC  a ) 
               
               
                   
               
               
                 Initial 
                 Clear, many fibrous particles, a few 
                 Clear, many fibrous particles, a few 
                 Clear, many fibrous particles, a few 
               
               
                   
                 small white particles 
                 small white particles 
                 small white particles 
               
               
                 Day 1 
                 Clear, some fibrous particles, a few 
                 Same 
                 FT Cycle 1 - same 
               
               
                   
                 small white particles 
                   
                   
               
               
                 Day 2 
                 Same 
                 Same 
                 FT Cycle 2 - same 
               
               
                 Day 5 
                 Clear, many fibrous particles, some 
                 Same 
                 FT Cycle 3 - same 
               
               
                   
                 small white particles 
                   
                   
               
               
                 Day 6 
                 Same 
                 Same 
                 FT Cycle 4 - same 
               
               
                 Day 7 
                 Same 
                 Same 
                 FT Cycle 5 - same 
               
               
                 Day 8 
                 Same 
                 Same 
                 FT Cycle 6 - Clear, many fibrous and 
               
               
                   
                   
                   
                 small white particles 
               
               
                 Day 9 
                 Same 
                 Same 
                   
               
               
                 Day 12 
                 Same 
                 Clear, many fibrous and some small 
                   
               
               
                   
                   
                 white particles, crystallization on 
                   
               
               
                   
                   
                 bottom/sides of vial 
                   
               
               
                 Day 13 
                 Same 
                 Same 
                   
               
               
                 Day 14 
                 Clear, many fibrous and small white 
                 Same 
                   
               
               
                   
                 particles (more than previous) 
               
               
                   
               
               
                 A portion of the pre-filtered solution was transferred into three 20 mL glass vials and placed at the respective storage conditions for visual observation. 
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekends. 
               
             
          
         
       
     
         [0000]    
       
         
               
               
             
               
               
               
               
             
           
               
                 TABLE 7C 
               
             
             
               
                   
               
               
                   
                 7A Post-filtration 
               
             
          
           
               
                 Observations 
                 Bottle 1 (at RT) 
                 Bottle 2 (at 4° C.) 
                 Bottle 3 (at FTC  a ) 
               
               
                   
               
               
                 Initial 
                 Clear, very few fibrous particles 
                 Clear, very few fibrous particles 
                 Clear, very few fibrous particles 
               
               
                 Day 1 
                 Clear, a few fibrous particles, one small 
                 Same 
                 FT Cycle 1 - Clear, few fibrous particles, 
               
               
                   
                 white particle 
                   
                 few small white particles 
               
               
                 Day 2 
                 Same 
                 Clear, a few fibrous particles, some small 
                 FT Cycle 2 - Clear, few fibrous particles, 
               
               
                   
                   
                 white particles 
                 very few small white particles 
               
               
                 Day 5 
                 Clear, a few fibrous particles 
                 Clear, a few fibrous particles, very few 
                 FT Cycle 3 - same 
               
               
                   
                   
                 small white particles 
                   
               
               
                 Day 6 
                 Same 
                 Same 
                 FT Cycle 4 - same 
               
               
                 Day 7 
                 Same 
                 Same 
                 FT Cycle 5 - same 
               
               
                 Day 8 
                 Same 
                 Same 
                 FT Cycle 6 - same 
               
               
                 Day 9 
                 Same 
                 Same 
                   
               
               
                 Day 12 
                 Same 
                 Same 
                   
               
               
                 Day 13 
                 Same 
                 Same 
                   
               
               
                 Day 14 
                 Same 
                 Clear, a few fibrous and small white 
                   
               
               
                   
                   
                 particles 
               
               
                   
               
               
                 Note: 
               
               
                 ?A portion of the twice-filtered solution was transferred into three 50 mL media bottles and placed at the respective storage conditions for visual observation. 
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekends. 
               
             
          
         
       
     
         [0053]    Ater nine days of observation, the post-filtration portion of Formulation 7A was split and a stir bar was added to each sample as, a seeding agent (the stir bar was not rotating). Visual observations were recorded and the results are shown in Table 7 D. 
         [0000]    
       
         
               
               
             
               
               
               
               
             
               
               
             
               
               
               
               
             
           
               
                 TABLE 7D 
               
             
             
               
                   
               
               
                   
                 7A Post-filtration 
               
             
          
           
               
                   
                 Bottle 1 (at RT) 
                 Bottle 3 (at 4° C.) 
                 Bottle 5 (at FTC  a ) 
               
             
          
           
               
                 Observations 
                 With Stir Bar Added As a Seeding Agent 
               
               
                   
               
             
          
           
               
                 Initial  b   
                 Clear, a few fibrous particles 
                 Clear, a few fibrous particles 
                 Clear, a few fibrous particles 
               
               
                 Day 3 
                 Same 
                 Clear, a few fibrous particles, very few 
                 FT Cycle 1 - Clear, a few fibrous 
               
               
                   
                   
                 small white particles 
                 particles, very few small white 
               
               
                   
                   
                   
                 particles 
               
               
                 Day 4 
                 Same 
                 Same 
                 FT Cycle 2 - same 
               
               
                 Day 5 
                 Same 
                 Same 
               
               
                   
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekend. 
               
               
                   b  Initial observations were performed prior to addition of stir bars. 
               
             
          
         
       
     
         [0054]    To other portions of composition 7A split after nine days of observation, excess olopatadine (a few small granules) was added to both the pre-filtration and post-filtration samples to determine if seeding would cause olopatadine to precipitate. Visual observations were recorded on the indicated days. The results are shown in Tables 7 E (unfiltered composition) and 7 F (filtered composition). 
         [0000]    
       
         
               
               
             
               
               
               
             
           
               
                 TABLE 7E 
               
             
             
               
                   
               
               
                 Obser- 
                 7A Pre-flltration (with excess olopatadine HCl) 
               
             
          
           
               
                 vations 
                 Bottle 1 (at RT) 
                 Bottle 2 (at FTC  a ) 
               
               
                   
               
               
                 Initial  b   
                 Clear, many fibrous particles, 
                 Clear, many fibrous particles, 
               
               
                   
                 some small white particles 
                 some small white particles 
               
               
                 Day 3 
                 Clear, many fibrous/small 
                 FT Cycle 1 - clear, many 
               
               
                   
                 white particles (powdery 
                 fibrous/small white particles 
               
               
                   
                 settling) 
                 (powdery settling) 
               
               
                 Day 4 
                 Same 
                 FT Cycle 2 - same 
               
               
                 Day 5 
                 Same 
               
               
                   
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekends. 
               
               
                   b  Initial observations were performed prior to addition of excess olopatadine HCl. 
               
             
          
         
       
     
         [0000]    
       
         
               
               
             
               
               
               
               
             
               
               
             
               
               
               
               
             
           
               
                 TABLE 7F 
               
             
             
               
                   
               
               
                   
                 7A Post-filtration 
               
             
          
           
               
                   
                 Bottle 2 (at RT) 
                 Bottle 4 (at 4° C.) 
                 Bottle 6 (at FTC  a ) 
               
             
          
           
               
                 Observations 
                 With Excess Olopatadine HCl Added (1-2 small granules) 
               
               
                   
               
             
          
           
               
                 Initial  b   
                 Clear, a few fibrous particles 
                 Clear, a few fibrous particles 
                 Clear, a few fibrous particles 
               
               
                 Day 3 
                 Clear, many fibrous and small white 
                 Clear, many fibrous and small white 
                 FT Cycle 1 - Clear, many 
               
               
                   
                 particles 
                 particles (powdery at bottom of vial, 
                 fibrous/small white particles (powdery 
               
               
                   
                   
                 settling) 
                 at bottom of vial, settling) 
               
               
                 Day 4 
                 Same 
                 Same 
                 FT Cycle 2 - same 
               
               
                 Day 5 
                 Same 
                 Same 
               
               
                   
               
               
                 A portion of the solutions that had been through nine days of observations at RT and 4° C. and four FT cycles were transferred into three 20 mL glass vials and spiked with olopatadine HCl. These units were then placed at the respective storage conditions for visual observation. 
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekends. 
               
               
                   b  Initial observations were performed prior to addition of excess olopatadine HCl. 
               
             
          
         
       
     
         [0055]    The stability of the composition “7B” (containing BAC and EDTA) was evaluated in the same fashion. The results are Shown in Tables 7G (Pre-filtration), 7H (Post-filtration), 71 (with stir bar added after 9 days), 7J (with excess olopatadine added after 9 days; pre-filtration), and 7K (with excess olopatadine added after 9 days; post-filtration). 
         [0000]    
       
         
               
               
             
               
               
               
               
             
           
               
                 TABLE 7G 
               
             
             
               
                   
               
               
                   
                 7B Pre-filtration 
               
             
          
           
               
                 Observations: 
                 Bottle 1 (at RT) 
                 Bottle 2 (at 4° C.) 
                 Bottle 3 (at FTC  a ) 
               
               
                   
               
               
                 Initial 
                 Clear, many fibrous particles, a few 
                 Clear, many fibrous particles, a few 
                 Clear, many fibrous particles, a few 
               
               
                   
                 small white particles 
                 small white particles 
                 small white particles 
               
               
                 Day 1 
                 Clear, some fibrous particles, small 
                 Same 
                 FT Cycle 1 - Same 
               
               
                   
                 white particles 
                   
                   
               
               
                 Day 2 
                 Same 
                 Same 
                 FT Cycle 2 - Same 
               
               
                 Day 5 
                 Clear, many fibrous particles, some 
                 Same 
                 FT Cycle 3 - Same 
               
               
                   
                 small white particles 
                   
                   
               
               
                 Day 6 
                 Same 
                 Same 
                 FT Cycle 4 - same 
               
               
                 Day 7 
                 Same 
                 Same 
                 FT Cycle 5 - same 
               
               
                 Day 8 
                 Same 
                 Same 
                 FT Cycle 6 - Clear, many fibrous and 
               
               
                   
                   
                   
                 small white particles 
               
               
                 Day 9 
                 Same 
                 Same 
                   
               
               
                 Day 12 
                 Same 
                 Same 
                   
               
               
                 Day 13 
                 Same 
                 Same 
                   
               
               
                 Day 14 
                 Clear, many fibrous and small white 
                 Same 
                   
               
               
                   
                 particles (more than previous) 
               
               
                   
               
               
                 A portion of the pre-filtered solution was transferred into three 20 mL glass vials and placed at the respective storage conditions for visual observation. 
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekends. 
               
             
          
         
       
     
         [0000]    
       
         
               
               
             
               
               
               
               
             
           
               
                 TABLE 7H 
               
             
             
               
                   
               
               
                   
                 7B Post-filtration 
               
             
          
           
               
                 Observations 
                 Bottle 1 (at RT) 
                 Bottle 2 (at 4° C.) 
                 Bottle 3 (at FTC  a ) 
               
               
                   
               
               
                 Initial 
                 Clear, very few fibrous particles 
                 Clear, very few fibrous particles 
                 Clear, very few fibrous particles 
               
               
                 Day 1 
                 Clear, a few fibrous particles 
                 Same 
                 FT Cycle 1 - Clear, few fibrous particles, 
               
               
                   
                   
                   
                 few small white particles 
               
               
                 Day 2 
                 Same 
                 Clear, a few fibrous particles, some small 
                 FT Cycle 2 - Clear, few fibrous particles, 
               
               
                   
                   
                 white particles 
                 very few small white particles 
               
               
                 Day 5 
                 Same 
                 Clear, a few fibrous particles, very few 
                 FT Cycle 3 - same 
               
               
                   
                   
                 small white particles 
                   
               
               
                 Day 6 
                 Same 
                 Same 
                 FT Cycle 4 - same 
               
               
                 Day 7 
                 Same 
                 Same 
                 FT Cycle 5 - same 
               
               
                 Day 8 
                 Same 
                 Same 
                 FT Cycle 6 - same 
               
               
                 Day 9 
                 Same 
                 Same 
                   
               
               
                 Day 12 
                 Same 
                 Clear, a few fibrous and small white 
                   
               
               
                   
                   
                 particles (more than previous) 
                   
               
               
                 Day 13 
                 Same 
                 Clear, a few fibrous/small white particles, 
                   
               
               
                   
                   
                 light layer of crystallization forming on 
                   
               
               
                   
                   
                 bottom/sides of bottle 
                   
               
               
                 Day 14 
                 Same 
                 Same 
               
               
                   
               
               
                 Note: 
               
               
                 A portion of the twice-filtered solution was transferred into three 50 mL media bottles and placed at the respective storage conditions for visual observation. 
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekends; 
               
             
          
         
       
     
         [0000]    
       
         
               
               
             
               
               
               
               
             
               
               
             
               
               
               
               
             
           
               
                 TABLE 7I 
               
             
             
               
                   
               
               
                   
                 7B Post-filtration 
               
             
          
           
               
                   
                 Bottle 7 (at RT) 
                 Bottle 9 (at 4° C.) 
                 Bottle 11 (at FTC  a ) 
               
             
          
           
               
                 Observations 
                 With Stir Bar Added 
               
               
                   
               
             
          
           
               
                 Initial  b   
                 Clear, a few fibrous particles 
                 Clear, a few fibrous particles 
                 Clear, a few fibrous particles 
               
               
                 Day 3 
                 Clear, a few fibrous particles, very few 
                 Clear, a few fibrous and small 
                 FT Cycle 1 - Clear, a few fibrous 
               
               
                   
                 small white particles 
                 white particles 
                 particles, very few small white 
               
               
                   
                   
                   
                 particles 
               
               
                 Day 4 
                 Same 
                 Clear, a few fibrous/small white 
                 FT Cycle 2 - Clear, a few fibrous and 
               
               
                   
                   
                 particles, powdery at bottom of vial, 
                 small white particles 
               
               
                   
                   
                 settling 
                   
               
               
                 Day 5 
                 Same 
                 Clear, settling on bottom, many very 
                   
               
               
                   
                   
                 fine white particles 
               
               
                   
               
               
                 Note: 
               
               
                 A portion of the solutions that had been through nine days of observations at RT and 4° C. and four FT cycles were transferred into three 20 mL glass vials with stir bars added and placed at the respective storage conditions for visual observation. 
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekends. 
               
               
                   b  Initial observations were performed prior to addition of stir bars. 
               
             
          
         
       
     
         [0000]    
       
         
               
               
             
               
               
               
             
           
               
                 TABLE 7J 
               
             
             
               
                   
               
               
                 Obser- 
                 7B Pre-filtration (with excess olopatadine HCl) 
               
             
          
           
               
                 vations 
                 Bottle 3 (at RT) 
                 Bottle 4 (at FTC  a ) 
               
               
                   
               
               
                 Initial  b   
                 Clear, many fibrous particles, 
                 Clear, many fibrous particles, 
               
               
                   
                 some small white particles 
                 some small white particles 
               
               
                 Day 3 
                 Clear, many fibrous/small 
                 FT Cycle 1 - clear, many 
               
               
                   
                 white particles (light powdery 
                 fibrous/small white particles 
               
               
                   
                 settling) 
                 (powdery settling) 
               
               
                 Day 4 
                 Same 
                 FT Cycle 2 - same 
               
               
                 Day 5 
                 Same 
               
               
                   
               
               
                 A portion of the pre-filtered solutions that had been through nine days of observations at RT and 4° C. and four FT cycles were transferred into three 20 mL glass vials and spiked with olopatadine HCl. The units were then placed at the respective storage conditions for visual observation. 
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekends. 
               
               
                   b  Initial observations were performed prior to addition of excess olopatadine HCl. 
               
             
          
         
       
     
         [0000]    
       
         
               
               
             
               
               
               
               
             
               
               
             
               
               
               
               
             
           
               
                 TABLE 7K 
               
             
             
               
                   
               
               
                   
                 7B Post-filtration 
               
             
          
           
               
                   
                 Bottle 8 (at RT) 
                 Bottle 10 (at 4° C.) 
                 Bottle 12 (at FTC  a ) 
               
             
          
           
               
                 Observations 
                 With Excess Olopatadine Added (1-2 small granules) 
               
               
                   
               
             
          
           
               
                 Initial  b   
                 Clear, a few fibrous particles 
                 Clear, a few fibrous particles 
                 Clear, a few fibrous particles 
               
               
                 Day 3 
                 Clear, many fibrous and small white 
                 Clear, many fibrous and small white 
                 FT Cycle 1 - Clear, many 
               
               
                   
                 particles 
                 particles (powdery at bottom of vial, 
                 fibrous/small white particles (powdery 
               
               
                   
                   
                 settling) 
                 at bottom of vial, settling) 
               
               
                 Day 4 
                 Same 
                 Clear, many fibrous/small white 
                 FT Cycle 2 - same 
               
               
                   
                   
                 particles, crystallization at bottom of 
                   
               
               
                   
                   
                 vial 
                   
               
               
                 Day 5 
                 Same 
                 Same 
               
               
                   
               
               
                 A portion of the solutions that had been through nine days of observations at RT and 4° C. and four FT cycles were transferred into three 20 mL glass vials and spiked with olopatadine HCl. These units were then placed at the respective storage conditions for visual observation. 
               
               
                   a  Freeze-thaw cycle performed at 24 hour freeze/24 hour thaw except over weekends. 
               
               
                   b  Initial observations were performed prior to addition of excess olopatadine HCl. 
               
             
          
         
       
     
       Example 12 
     Effect of Phosphate Buffer 
       [0056]    The compositions shown below in Table 8 were prepared using a compounding procedure similar to that described in Example 1. In all four cases, the NaCl was added after olopatadine during the compounding. All four compositions contained the equivalent of 110% of a 0.6% targeted concentration. Two of the compositions were formulated at a pH of 3.95 and two at 4.10 to test an extreme condition. The results are shown in Table 8. 
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                 TABLE 8 
               
               
                   
               
               
                   
                 Formulation 12A 
                 Formulation 12B 
                 Formulation 12C 
                 Formulation 12D 
               
               
                   
                 % (w/v) 
                 % (w/v) 
                 % (w/v) 
                 % (w/v) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Olopatadine HCl 
                 0.732 
                 0.732 
                 0.732 
                 0.732 
               
               
                 Benzalkonium Chloride 
                 0.01 
                 0.01 
                 0.01 
                 0.01 
               
               
                 Disodium EDTA 
                 0.01 
                 0.01 
                 0.01 
                 0.01 
               
               
                 Sodium Chloride 
                 0.41 
                 0.41 
                 0.8 
                 0.8 
               
               
                 Dibasic Sodium Phosphate, 
                 0.5 
                 0.5 
                 — 
                 — 
               
               
                 Anhydrous 
                   
                   
                   
                   
               
               
                 Sodium Hydroxide 
                 pH to 3.95 
                 pH to 4.10 
                 pH to 3.95 
                 pH to 4.10 
               
               
                 Hydrochloric Acid 
                 pH to 3.95 
                 pH to 4.10 
                 pH to 3.95 
                 pH to 4.10 
               
               
                 Purified Water 
                 qs 100% 
                 qs 100% 
                 qs 100% 
                 qs 100% 
               
               
                 Visual Observations: 
                   
                   
                   
                   
               
               
                 Initial 
                 Clear solution 
                 Clear solution 
                 Clear solution 
                 Clear solution 
               
               
                 Room Temperature (4 days) 
                 Remained clear 
                 Remained clear 
                 Remained clear 
                 Remained clear 
               
               
                 4° C. (4 days) 
                 Remained clear on days 
                 Remained clear on days 
                 Remained clear on days 
                 Remained clear on days 
               
               
                   
                 1, 2, 3 and 4. No 
                 1, 2, and 3. On day 4, 
                 1, 2, 3, and 4. No 
                 1, 2, and 3. On day 4, 
               
               
                   
                 precipitate was found. 
                 a very small amount of 
                 precipitate was found. 
                 a significant amount of 
               
               
                   
                   
                 clear crystals formed 
                   
                 clear crystals formed 
               
               
                   
                   
                 at the bottom of the 
                   
                 at the bottom of the 
               
               
                   
                   
                 glass vial. 
                   
                 glass vial. 
               
               
                   
               
               
                 Comparing the results of Formulations B and D demonstrates that compositions with phosphate buffer are more stable against crystal formation than compositions without phosphate buffer. 
               
             
          
         
       
     
       Example 13 
     Storage Stability 
       [0057]    The solution stability of the composition of Example 1 was examined by preparing variations of the composition at the pH&#39;s shown in Table 9 and subjecting the samples to 13 freeze-thaw cycles (same cycles as described in Example 11 above). Following the last cycle, the samples were stored in the freezer for approximately three weeks and then analyzed. The amount of olopatadine (pre- and post-filtration, 0.2 μM filter) was determined by HPLC assay as a percent of the labeled amount (0.6%). The samples were evaluated using four tests of solution clarity: “Nephelos” values were obtained using a turbidimeter (HF Scientific, Inc., Model No. DRT100B); “Clarity” was determined by visual observation using a method similar to the Ph. Eur. (5 th  Edition) method for evaluating solution clarity and degree of opalescence; “Precipitate” was determined by visual inspection and the presence of absence of precipitates was recorded; “Particles by Visual Observation” was determined by visual inspection under a light box where not more than 3 particles per 5 mL sample is considered “essentially particle free.” Osmolality and pH were also determined for each composition. The results are shown in Table 9. In four of the five cases (Samples 1-4), the compositions were clear solutions following the freeze-thaw cycling study, demonstrating the composition of Example 1 is a stable aqueous solution despite the absence of a polymeric physical stability-enhancing agent. The sample that did not remain a clear solution is Sample 5 (pH=4.45). 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 9 
               
             
             
               
                   
               
               
                   
                 Olopatadine Assay 
                 Pre filtration Physical Test Results 
               
             
          
           
               
                   
                 (% of label) 
                   
                   
                   
                 Partiales by 
                   
                   
               
             
          
           
               
                 Sample 
                 Pre- 
                 Post- 
                 Nephelos 1   
                   
                   
                 Visual 
                 Osmolality 
                   
               
               
                 Lot 
                 Filtration 
                 Filtration 
                 (In NTU) 
                 Clarity 
                 Precipitate 
                 Observation 
                 mOsm/Kg 
                 pH 
               
               
                   
               
             
          
           
               
                 1 
                  99 
                 100 
                 0.3 
                 Clear, 
                 None 
                 Essentially 
                 280 
                 3.83 
               
               
                   
                  99 
                  99 
                   
                 NMT 
                   
                 particle-free 
                   
                   
               
               
                   
                   
                   
                   
                 EP1 
                   
                   
                   
                   
               
               
                 2 
                  99 
                 100 
                 0.2 
                 Clear, 
                 None 
                 Essentially 
                 288 
                 3.94 
               
               
                   
                  97 
                  99 
                   
                 NMT 
                   
                 particle-free 
                   
                   
               
               
                   
                   
                   
                   
                 EP1 
                   
                   
                   
                   
               
               
                 3 
                 100 
                 101 
                 0.2 
                 Clear, 
                 None 
                 Essentially 
                 285 
                 4.01 
               
               
                   
                  98 
                  99 
                   
                 NMT 
                   
                 particle-free 
                   
                   
               
               
                   
                   
                   
                   
                 EP1 
                   
                   
                   
                   
               
               
                 4 
                  98, 
                  98 
                 0.5 
                 Clear, 
                 None 
                 Essentially 
                 287 
                 4.15 
               
               
                   
                  99, 
                  99 
                   
                 NMT 
                   
                 particle-free 
                   
                   
               
               
                   
                   
                   
                   
                 EP1 
                   
                   
                   
                   
               
               
                 5 
                  98 
                  98 
                 (a) Crystal 
                 Clear, 
                 None 
                 Essentially 
                 294 
                 4.45 
               
               
                   
                  98 
                  98 
                 Form In one 
                 NMT 
                   
                 particle-free 
                   
                   
               
               
                   
                   
                   
                 Test Tube 
                 EP1 
                   
                   
                   
                   
               
               
                   
                   
                   
                 (b) Other 
                   
                   
                   
                   
                   
               
               
                   
                   
                   
                 test tube 
                   
                   
                   
                   
                   
               
               
                   
                   
                   
                 clear 
                   
                   
                   
                   
                   
               
               
                   
                   
                   
                 (0.6, 0.5) 2   
               
               
                   
               
               
                   1 Nephelos (Turbidity) of ≦3 NTU is considered clear solution as per Ph. Eur. (5 th  Ed.) 
               
               
                   2 Pre and post olopatadine assay, nephalos, clarity, precipitate, particles by visual observation, osmolality and pH were performed using clear solution from second test tube. 
               
             
          
         
       
     
         [0058]    This invention has been described by reference to certain preferred embodiments; however, it should be understood that it may be embodied in other specific forms or variations thereof without departing from its special or essential characteristics. The embodiments described above are therefore considered to be illustrative in all respects and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description.