Abstract:
A nozzle is provided herein for ophthalmic dispensers which is configured to accommodate microdosing. The nozzle includes a converging pathway. Preferably, the pathway converges so as to impart momentum to liquid passing therethrough through an increase of velocity. A tapered portion may be provided flared openly from the inlet to best accept liquid flow thereinto and provide a funneling effect into the flowpath. Preferably, the flowpath terminates at an outlet which is internally un-radiused and circumscribed by a chamfered surface.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a National Stage Application under 35 U.S.C. §371 of PCT International Application No. PCT/US2013/030882, filed Mar. 13, 2013, which claims priority to U.S. Provisional Patent Application No. 61/610,138, filed on Mar. 13, 2012, the entire contents of which are incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to nozzles for ophthalmic dispensers. 
         [0003]    Various dispensers for delivering medicament, and other active ingredients, to the eye are known in the prior art. Eye droppers and dropper bottles are used extensively to deliver liquid doses to the eyes of patients. Typical droppers and dropper bottles can only produce dose volumes of certain sizes, with no ability to provide smaller doses. As such, it is well recognized that a large percentage of administered ophthalmic liquid that is administered topically is lost by drainage, either externally or through nasolacrimal drainage. 
         [0004]    Dispensers have been developed in the prior art which can generate dose sizes in much smaller volumes than those provided by typical droppers and dropper bottles, such doses being in the range of 5-15 microliters. Dispensers for delivering such doses are known in the prior art, such as U.S. Pat. No. 5,152,435, which issued Oct. 6, 1992; U.S. Pat. No. 5,881,956, which issued Mar. 16, 1999; U.S. Pat. No. 6,513,682, which issued Feb. 4, 2003; U.S. Pat. No. 6,854,622, which issued Feb. 15, 2005; U.S. Pat. No. 6,991,137, which issued on Jan. 31, 2006; U.S. Pat. No. 7,014,068, which issued on Mar. 21, 2006; U.S. Pat. No. 7,073,733, which issued on Jul. 11, 2006; U.S. Pat. No. 7,131,559, which issued on Nov. 7, 2006; U.S. Pat. No. 7,207,468, which issued on Apr. 24, 2007; U.S. Pat. No. 7,261,224, which issued on Aug. 28, 2007; and U.S. Pat. No. 7,651,011, which issued on Jan. 26, 2010. These references are all incorporated by reference herein. 
         [0005]    The aforesaid dispensers may achieve microdosing with doses in the range of 5-15 microliters. With such microdosing, concerns exist over repeatability within a target range. With such small doses, slight variability impacts the dose size. 
       SUMMARY OF THE INVENTION 
       [0006]    A nozzle is provided herein for ophthalmic dispensers which is configured to accommodate microdosing. The nozzle includes a converging pathway. Preferably, the pathway converges so as to impart momentum to liquid passing therethrough through an increase of velocity. A tapered portion may be provided flared openly from the inlet to best accept liquid flow thereinto and provide a funneling effect into the flowpath. Preferably, the flowpath terminates at an outlet which is internally un-radiused and circumscribed by a chamfered surface. 
         [0007]    To further enhance the ability of the nozzle to administer repeated uniform doses, one or more of the liquid-contacting surfaces may be treated to be hydrophobic. Additionally, surfaces surrounding liquid-contacting surfaces may be also treated to be hydrophobic. 
         [0008]    Advantageously, with the subject invention, a nozzle is provided which can direct a dose for administration, with minimal attraction to the nozzle. 
         [0009]    These and other features of the invention will be better understood through a study of the following detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a front perspective view of a nozzle formed in accordance with the subject invention; 
           [0011]      FIG. 2  is a rear elevational view of a nozzle formed in accordance with the subject invention; 
           [0012]      FIG. 3  is a side elevational view of a nozzle formed in accordance with the subject invention; 
           [0013]      FIG. 4  is a cross-sectional view taken along line  4 - 4  of  FIG. 3 ; 
           [0014]      FIG. 5  is a series of stop-motion photographs showing delivery of a dose by a prior art nozzle; and 
           [0015]      FIG. 6  is a series of stop-motion photographs showing delivery of a dose by a nozzle formed in accordance with the subject invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    With reference to the Figures, a nozzle  10  is provided. The nozzle  10  is particularly well-suited for administering microdoses, e.g., ophthalmic doses in the range of 5-15, even 5-20, microliters. 
         [0017]    As shown in the Figures, the nozzle  10  is preferably a unitary piece manufactured separately from other components, such as pump components. Preferably, the nozzle  10  is formed from thermoplastic material and is preferably formed by molding. By being separately formed, the tolerances of the nozzle  10  may be tightly controlled. Although less preferred, the nozzle  10  may be formed integrally with other components of a pump. 
         [0018]    The nozzle  10  includes an elongated, tubular nozzle portion  12  which defines a liquid pathway  14  therethrough. The liquid pathway  14  extends between an inlet  16  and an outlet  18  so that liquid introduced through the inlet  16  may pass to the outlet  18  through the liquid pathway  14 . 
         [0019]    The liquid pathway  14  is preferably elongated having a length  1  which is more than eight times greater than diameter dl of the outlet  18 . The length  1  may be more than ten times greater than diameter d 1  of the outlet  18 . Preferably, the liquid pathway  14  is formed to be convergent from the inlet  16  to the outlet  18 . With this arrangement, liquid passing through the liquid pathway  14  experiences a momentum buildup through an increase of velocity while travelling from the inlet  16  to the outlet  18 . The momentum buildup allows for a dose to be delivered at a higher velocity. This allows for the dose to be delivered in a more compact, less broken-up manner. Ideally, a dose of a singe drop is delivered. If sufficient momentum is not imparted, microbubbles form in the liquid with the dose possibly breaking up to some extent. 
         [0020]    Preferably, the convergence is only slight so that the flow characteristics of the liquid passing through the liquid pathway  14  are only slightly altered. In addition, fluid turbulence is minimized. It is preferred that the convergence be at a constant rate from the inlet  16  to the outlet  18 . Preferably, the angle of convergence a is in the range of 0.25-1.0 degrees relative to the longitudinal axis CL of the liquid pathway  14 . With the convergent arrangement of the liquid pathway  14 , the inlet  16  is provided with a larger diameter than the outlet  18 . Preferably, the ratio of the diameter d 2  of the inlet  16  to the diameter d 1  of the outlet  18  is in the range of 1.05-1.6, more preferably 1.05-1.5, more preferably 1.05-1.4, more preferably 1.05-1.3, more preferably 1.05-1.2, more preferably 1.05-1.1, and most preferably 1.08. 
         [0021]    Preferably, a tapered portion  20  extends, and diverges away, from the inlet  16 . This provides an enlarged opening to receive liquid which is then funneled through the tapered portion  20  into the liquid pathway  14 . The tapered portion  20  includes an inner edge  22  which preferably extends continuously from the inlet  16 . The inner edge  22  is defined with the taper of the tapered portion  20 . The taper may be provided with the inner edge  22  being arcuate, chamfered and combinations thereof. Surface interruptions such as straight wall portions or ledges may be provided on the inner edge  22 , particularly if such enhances manufacturability. With the tapered portion  20 , an overall decrease in diameter towards the inlet  16  is provided, such decrease in diameter being continuous or discontinuous. 
         [0022]    The tapered portion  20  also desirably may reduce vorticity imparted to the liquid as being delivered through the nozzle  10 . Changes in direction in flow may cause liquid to have vorticity, which can also lead to dose break-up. A laminar flow is ideally sought. With typical pump arrangements, liquid is caused to significantly change direction (e.g., a 90° change in direction) in being fed from a fluid path and into a nozzle. A significant change in direction may impart vorticity. The tapered portion  20  may ameliorate this effect by allowing the liquid to traverse a tapered inlet into the nozzle  10  with a more gradual change of direction being applied than if no tapered portion  20  was provided. This is more advantageous where an inlet fluid path is positioned at a generally right angle relative to the nozzle  10 . 
         [0023]    It is also preferred that the nozzle portion  12  be formed with the outlet  18  being internally un-radiused (the outlet  18  lying wholly in a plane perpendicular to the longitudinal axis CL) and with a reduced diameter section  24  about the outlet  18 . As shown in the Figures, the reduced diameter section  24  preferably is a chamfered section which extends from the outlet  18  and flares inwardly therefrom so as to minimize portions of the nozzle portion  12  being within a plane coinciding with the outlet  18  (the plane being perpendicular to the longitudinal axis CL). With this arrangement, a liquid dose discharged from the outlet  18  will have minimal surface contact with the nozzle portion  12  about the outlet  18 . 
         [0024]    To further enhance the ability of the nozzle  10  to administer repeated uniform doses of liquid, the liquid pathway  14  is preferably treated to be hydrophobic. Various techniques may be utilized for hydrophobic treatment, including plasma treatment. In this manner, capillary, or other attraction, may be minimized between the nozzle  10  and the dose. Such attractive force may disrupt the dose during delivery. Portions surrounding the liquid pathway  14 , such as the tapered portion  20  and the reduced diameter section  24 , may be also hydrophobically treated. It may be most practical to treat the entire nozzle  10  hydrophobically. 
         [0025]    To permit mounting of the nozzle portion  12 , a mounting ring  26  may extend from the nozzle portion  12 . Preferably, the mounting ring  26  is bowl-shaped. The mounting ring  26  circumscribes the nozzle portion  12  such that the outlet end of the nozzle portion  12  is on the inner side of the bowl of the mounting ring  26 . Preferably, a portion of the nozzle portion  12  extends rearwardly from the mounting ring  26  so that the inlet  16  is spaced from the mounting ring  26 . It is also preferred that the outlet  18  extend beyond the mounting ring  26  so as to be located exteriorly thereof (e.g., the outlet  18  is located beyond rim  28  of the mounting ring  26 ). 
         [0026]      FIG. 5  includes a series of photographs showing with stop-motion photography, the delivery of a 6.5 μL dose of water purified by reverse osmosis with methylene blue dye using a prior art nozzle with a pump. The nozzle includes a 0.179 inch liquid pathway which diverges to an outlet having a diameter of 0.0502 inches with an internal tip radius of 0.005 inches. 
         [0027]    FIG. 6 includes a series of photographs showing with stop-motion photography, the delivery of a 19.8 μL dose of water purified by reverse osmosis with methylene blue dye using a nozzle formed in accordance with the subject invention and using the same type of pump as discussed with respect to  FIG. 5 . The nozzle here includes a 0.315 inch liquid pathway converging from a inlet of 0.039 inches to an outlet of 0.036 inches with the outlet having no internal tip radius. In addition, the liquid pathway is hydrophobically treated. 
         [0028]    As can be seen, the dose delivered with the nozzle in  FIG. 6  is more directed than with the prior art nozzle of  FIG. 5 . It is noted that the dose in  FIG. 6  has some break-up into smaller drops. However, overall dose is delivered more intact as a single unit with the nozzle of  FIG. 6  as compared with the dose of  FIG. 5 . This aides in delivering a maximum amount of a dose. Further to the extent a dose breaks up, the smaller drops maintain better linearity in being delivered by the nozzle of  FIG. 6  as compared with the delivery of the dose of  FIG. 5 . This results in a greater amount of dose reaching a target site.