METHOD FOR PRODUCING A CONTROLLED-RELEASE PREPARATION

Abstract: The invention concerns a method for producing a controlled-release pharmaceutical preparation with a particle-containing coating, the coating being derived from an aqueous dispersion of a film-forming water insoluble polymer and a water soluble pore-forming agent. By suspending, instead of dissolving the pore-forming agent, the resulting coating will contain particles of the pore-formers with a predetermined size that creates, when disintegrated or dissolved in the body fluid, canals or a network of pores through the polymer film. Due to this network, the film will get a good mechanical stability and are left intact after the release of the drug.

Description: cording to these two patents the permeability of the polymer is increased by including a water-soluble material in the polymer. The coating including the water soluble material is obtained by dissolving the water soluble material in the aqueous dispersion of a film- forming polymer. When such a preparation is subsequently swallowed and contacted with the GI juices the water soluble material dissolves and make the polymer coating micro-porous and increase the release rate of the drug through the coating. The sizes of the micro-pores correspond to those of the dissolved molecules. An advantage with medical preparations prepared according to these two patents is that they may be prepared without organic solvent. A disadvantage is that the mechanical strength of the coating is poor, when the permeability is increased to an acceptable level for moderately soluble drugs, especially for tablets. Another disadvantage is that the size of the pores is not controlled which means e.g. that it is difficult to obtain reproducible products. The permeability increasing or pore-forming agents used according to the two above methods may be identical chemically but the physical state of these agents in the coating solution is different. OBJECT OF THE INVENTION An object of the present invention is therefore to accomplish a method for producing a controlled-release pharmaceutical preparation having the same effective release rate and mechanical strength as the one described in US 4,557,925 while avoiding the use of organic sol- vents and the problems arising by using the method according to US 5,472,712 and 5 639 476. SUMMARY OF THE INVENTION This object as well as other objects that will be apparent from the description below, have now been ob- tained according to the present invention by providing a method for producing an essentially zero order, con- ω ω t_o to I- 1 LΠ o LΠ o LΠ O LΠ Hj rf Pi 0 μ- rf rt μ- H Ω Pi TJ rt _- ■ 3 PJ £ 0 Hi rt Pi Ω TJ tr μ- tr CQ TJ Ω rt Φ tr μ- ø ø tr tr rt tr 0 φ ϋ 0 tr Φ μ- 0 μ- Hi μ- μ- Hi 0 0 PJ ø μ- ø Hi _- ■ Hj Hi φ CQ LQ 0 Φ ^ φ 3 Ω 0 Φ J ø Pi rt ø Ω ^ J H <1 CQ _- ■ CQ φ Φ 0 Φ TJ 0 CQ ø 1 rf LQ ^ CQ Φ tr rt PJ μ- rt Φ μ- 0 μ- TJ TJ M Hj PJ φ ø rt TJ PJ Ω μ- μ- • 3 Ω Φ P. 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Hi Hi Hi o CQ Pi Pi rt ø PJ CQ H 0 0 Φ J μ- φ rf μ- tr Φ £ μ- tr 0 0 0 s; φ PJ 0 J φ ^ ) TJ Hi tr LQ ∞ Pi Hi Φ Φ ø Hi tr rt 0 Hj μ- rt Φ μ- Hi μ- rt Hi rf LQ rt CJ. 3 & 0 0 0 φ s Hi 3 TJ 3 LQ rt 0 tr <1 3 _- ■ rt tr rt Ω 3 tr 0 Φ μ- Φ Φ φ 0 Hj LQ Pi Ω tr ø o μ- μ- o CQ Φ μ- tr Φ ^ φ φ Φ Pi Pi 0 H Hj Φ φ 1 0 TJ PJ μ- 0 Ω ø Hj rf PJ μ- rt ø LQ Φ 0 CQ Hi rt 3 0 1 Ω Ω PJ tr Ω μ- LQ φ 0 LQ 0 TJ TJ Φ tr φ CQ TJ Hj CQ Ω TJ CQ rf Ω μ- μ- 0 Hi 0 0 rt PJ J φ rf Φ 1 Φ rt Hj τ3 J P. φ rt Φ 0 tV 0 . 0 o Φ J O ω ø ø CQ 0 0 3 μ- Hj ø CQ tr ø ^ Ω tr 0 J φ Φ Hi Hi 0 Hi tr ϋ ø φ Hj rt TJ . 0 t Hj 3 Ω Φ r Hj Φ rt Ω TJ PJ LQ TJ 0 si rt Φ Φ Φ CQ Pi 0 Pi 3 J Hi LQ PJ Φ 0 Φ • rt J PJ 3 Φ φ 0 0 3 l- P tr J 1 Ω Φ TJ Hj μ- μ- μ- μ- Ω Pi H o > < O J CO ϋ 0 φ Hi 0 Hj Φ Φ μ- Hi rt rf Φ PJ P. CQ ø ø CQ PJ φ 0 rt 0 rt 0 PJ φ Pi rt Φ rt Pi Φ Hj Ω TJ ø ø 0 μ- • μ- 0 3 φ TJ LQ μ- φ Ω 0 CQ tr μ- μ- Hi Pi Φ PJ CQ J J Hi 0 rt Pi O Hj Φ ø m Ω rf 0 rf Φ ø Ω ø <5 rt PJ Hi CQ μ- 3 Ω 0 rf rt Ω 3 ø tr φ ø Hj PJ LQ O μ- I- 1 tr Hi CQ 0 LQ φ Φ tr 3 CQ Φ ø Φ 0 0 PJ μ- ør 0 μ- pi ø rt CQ LQ rt Hj Ω 0 μ- o 3 Pi Hi PJ o rf Ω Hi J Φ Φ 3 ø o rt rt 0 μ- φ CQ tr P. PJ ω tr CQ tr TJ J <j ø O Hj J tr rf CQ ø TJ LQ Hi tr rt 0 0 o Φ μ- μ- J 0 PJ LQ tr rt Φ 0 l-h J Ω PJ Ω μ- rt rt PJ Φ tr 0 Hi 0 rt ø _-> Ω ø tr rt Φ ■ <: tr rt rt rt ø PJ ø 0 - PJ Hi J rt Φ Hi 0 μ- CQ LQ TJ μ- 0 P μ- 0 Φ PJ rt Φ μ- 0 LQ Hj tr J LQ tr 0 Hj Hj 0 0" P- rt ii rt ø φ tr rt rt 0 tr PJ Ω PJ rt h- 1 rt φ Φ tr Φ CQ 3 Hi PJ Φ rt Φ > < rf CQ tr Hj LQ Hi Φ 3 Hi PJ \-> PJ TJ tr φ μ- ø rf μ- ' 0 < Ω TJ 0 TJ % Φ 0 μ- φ 0 Φ φ 0 J rt CQ 0 O Φ rt < rf rt PJ ø h- 1 PJ PJ μ- 0 CQ PJ • X Hi ø Hi 0 Hi TJ < < Φ • Pi Hj CQ Φ - ^ μ- μ- ø Hi Ω Hi rf Hi TJ TJ Φ Pi μ- o Hi CQ Φ Φ μ- TJ ø Pi Ω Hi LQ Φ o h- 1 PJ μ- rt Hi TJ Hi J i tr rf α rt CQ CQ ^ rf Φ Φ 0 μ- -. Hi PJ rt rf Ω tr 0 0 Φ CQ 3 3 Φ Φ rt J 0 tr TJ tr - TJ J J • • μ- μ- tr μ- Φ TJ Hi CQ Φ Φ 1 tr tr Φ Φ 0 PJ rf I- 1 Φ J rf 3 3 0 μ- φ φ φ Φ Ω Hi Hi 0 φ μ- Hi Hi tr PJ PJ CQ Hj μ- 1 tr ø CQ ø J Hj 1 ø 0 tr 0 0 tr _- ■ rt P rt Φ Hi Ω 3 0 rt 0 Hi PJ H r Λ rf Hi rt Hi PJ Hj Hi rt Hi μ- 0 Hj PJ μ- ø LQ 0 0 CQ μ- LQ 0 . Hi ø μ- 0 ø -s 3 3 J φ rf 0 Ω Φ PJ ø TJ Ω Hj J μ- φ ^ Φ Φ Hj μ- rf μ- μ- μ- μ- I- 1 ■ <! rt LQ TJ Ω rt 0 Φ CQ 3 0 rt J o CQ 3 0 tr Ω ø ø 0 Φ tr Hj φ 0 TJ μ- rr 0 Φ C μ- Ω tr rt CQ ø Φ <! φ PJ LQ LQ φ J PJ μ- μ- Φ CQ 0 PJ ø CQ CQ CQ ø φ ø 0 CQ 0 Hi φ Pi CQ ø Q Q Pi rf Hj LQ J μ- T LQ Pi J Hi I- 1 Hi ø P. TJ J φ P. φ Pi J rt 0 0 0 Φ Φ 0 Ω Ω rt Hj CQ 0 LQ tr ø Hj rf μ- Ω μ- 0 Pi ø Hi 0 CQ TJ tr 0 tr O μ- 0 rf Φ * • <: o rt φ Φ Φ CQ rt Ω Hi CQ ≤ 0 PJ μ- PJ Φ I o LQ J ■ <: 0 Hi tr rt 1 ii CQ Φ TJ rt μ- J I-" Hj CQ φ rt μ- 0 tr 3 rt CQ Φ 1 0 Pi Φ rt J J tr 0 rf 0 rt μ- 0 μ- PJ μ- φ Φ rf 0 CQ tr Hi 0 Φ 0 Φ 1 μ- μ- ø LQ ø μ- 0 H- 1 Hj μ- 1 tr Hj <1 φ 1 Pi Hj 1 ø LQ - 1 CQ P. 1 • ø φ ? Φ DETAILED DESCRIPTION OF THE INVENTION The critical pore-forming agent must be a pharmaceutically acceptable substance that can be added to the aqueous dispersion of the film-forming polymer without being completely dissolved. Important factors for the pore-forming agent are its solubility and mean particle size. The solubility of the pore-forming agent is below 200 mg/ml in the coating solution at 25°C. Preferably the solubility is below 100 mg/ml, more preferably below 50 and most preferably below 30 mg/ml. The mean particle size of the pore-forming agent when added to the coating solution is 0.1-500 μm, preferably 0.5-100 μm and most preferably 1.0-25 μm. If larger particles are used it will be difficult to get reproducible preparations and if smaller particles are used manufacturing problems are expected. The predetermined amount of solid particles of the pore-forming agent in the coating solution is selected by the man skilled in the art in view of the specific drug and polymer used and the desired release rate. In a preferred embodiment of the invention the pore- forming agent is selected from the group consisting of potassium hydrogen tartrate (potassium bitartrate) , cre- atine, aspartic acid, glutamic acid and inosine. Other preferred pore-forming agents are chitosan and poly (butyl methacrylate, (2 -dimethyl aminoethyl) methac- rylate, methyl methacrylate) 1:2:1. Other pore-forming agents which may be used selected from a group consisting of potassium salts, calcium salts, magnesium salts, amino acids, week acids, carbohydrates, polymers with amino and/or acid functions. Examples are aspargine, glutamine, leucin, neroleucine, iso- leucine, magnesium citrate, magnesium phosphate, magnesium carbonate, magnesium hydroxide, magnesium oxide or a composition wherein at least one component is selected from one of these substances . The pore-former can also be a composition wherein at least one of the components is selected from one of these groups . The film-forming polymer according to the present invention could be any pharmaceutically acceptable water insoluble or essentially insoluble polymer, block- or co- polymer that can be dispersed in an aqueous solution. Example of such polymers are polymers selected from the groups consisting of cellulose esters, acrylic polymers, polyvinyl acetates, polyvinyl chlorides or a composition wherein at least one component is selected from one of the groups . Preferred substances are polyvinylacetate, polyme- thylmetacrylate or a terpolymer of vinylchloride, vinyl- alcohol and vinylacetate . Commercialy available latexes, pseudolatexes and polymer emulsions are also possible to use for the coating. Other preferred coating polymers are ethylcellulose, celluloseacetate, celluloseacetatebutyrate, celluloseace- tatepropionate, nitrocellulose, polymethyl-methacrylate, poly (ethylacrylate, methylmetacrylate) , polyvinylacetate, polyvinylchloride, polyethylene, polyisobutylene, poly (ethylacrylate, methylmetacrylate, trimethylamo- nioethylmetacrylatchloride) . In another preferred embodiment of the invention the coating-agent is a water-dispersion of the terpolymer from US 4,557,925, consisting of 80-95% by weight of polyvinylchloride, 0,5-19% by weight of polyvinylacetate and 0,5-10% by weight of polyvinylalcohol . In another preferred embodiment of the invention the coating polymer is a copolymer consisting of 50-100% by weight of polyvinylchloride and 0-50% by weight of polyvinylacetate . The weight ratio, amount of pore-forming agent to total weight of the dry coating, depends on the chosen polymer and pore-former and the release pattern desired, ω > to M Π o cπ O σι o cπ 3 HI 0 μ- 0 M rt Φ ^r m Hi Hj PJ o rt 3 . J o ø o PJ Ω J Ω rf φ M J φ 3 Hi u 1 PJ μ- r φ Φ ø Pi rf CQ tr rt 0 0 3 ii μ- PJ LQ μ- Φ rt * ! Ω 0 0 H3 Pi tr μ- φ rt μ- Ω 0 ø ø Hj μ- ø Hi LQ O Hi 3 J Φ x PJ rt 3 J TJ W M Φ Φ place in the coating equipment or in a separate dryer as for example in a drying chamber or a drying vessel . The drug in the solid core could for example be tranquillizers, antibiotics, hypnotics, antihyperten- sives, antianginics, analgesics, antiinflamatories, neu- roleptics, antidiabetics, diuretics, antikolinergics, an- tihyperacidics, antiepileptics, ACE inhibitors, β-recep- tor antagonists and agonists, anaesthetics, anorexiants, antiarrythmics, antidepressants, anticoagulants, antidi- arrhoetics, antihistamines, antimalariels, antineoplas- tics, immunosuppressives, antiparkinsonians, antipsychot- ics, antiplatelets, diuretics or antihyperlipidics . The drug substance could for example be potassium chloride, theophylline, a theophylline salt, phenylpro- panolamine, sodium salicylate, paracetamole, carbidopa, levodopa, diltiazem, enalapril, verapamil, naproxen, pseudoephedrin, nicorandil, oxybutuin, morphine, oxyco- done or propranolol . The aqueous suspension of pore-former and polymer can be diluted with an organic solvent up to 20%, preferably up to 10% and most preferably up to 5%. The organic solvent plasticises the polymer to enhance film formation. The organic solvent also decreases the solubility of the pore-former in the suspension. Thus by us- ing a small amount of organic solvent some advantages may be obtained and, compared with the presently used system, the amount of organic solvent can be reduced. According to the preferred embodiment no organic solvent is included. In its method aspect, the present invention is not limited by the drug or type of drug incorporated in the preparation. Any composition containing any presently known or future discovered orally acting drug may be coated in order to provide the highly advantageous con- trolled release pharmaceutical preparations of the present invention. Furthermore, and to the best of our knowledge, the preparations per se including the preferred pore-forming agents mentioned above are not previously known or even suggested. The invention is further illustrated by, but should not be limited to, the following preparations and example. Example Core The composition of the core is shown in table 1. The ingredients are granulated in a high shear mixer, dried and milled thereafter. The material is blended with lubricants and then compressed to tablets in a tablet press. TABLE 1 *Ξvaporates during the process Coating suspension The composition of a coating is shown in table 2. The coating suspension was prepared by adding the polymer dispersion, the pore former (with a specific particle size of 25μm) and deionised water to a final content of dry substances of 15% w/w, to a container with continuous stirring. TABLE 2 *Evaporates during the process Coatincf The cores were coated with the coating suspension in a coating pan. The coated tablets were allowed to dry in the pan for 15 minutes. Different embodiments of the preparation according to the invention, shown in table 3, were made accordingly. TABLE 3 1 KHT=Potassium bitartrate 2 PVAc=Polyvinylacetate 3 100 mg of Polyethyleneoxid is included in the formulation 4 P (EA-MMA) =Poly (ethylacrylate-methylmethacrylate) 2:1 Results Table 4 shows results from an in vitro dissolution test (according to USP 23, paddle method) with the formulations from table 3. Batch number 1 and 2 with no added pore-former have a very slow release pattern. The addition of pore-former (batch 3-5) increases the release rate and makes it pos- sible to design formulations according to a desired release pattern. Batch 2 and 4 had comparable drug-release rates. However, the polymer films from batch 2 ruptured during the analysis. Batch 4 showed much less variability in drug release compared to batch 2 and the polymer film still had good mechanical strength after the analysis. TABLE 4 After the 24 h in vitro dissolution test the tablet residuals (= the polymer films filled with water) were tested for mechanical strength (MS) . The force required to crack the polymer film was recorded. The following results were obtained. TABLE 5 Batch 1 2 3 4 5 MS (N) - 0 20 27 18 The same test performed on preparations according to the US patent 5 472 612 demonstrated that the polymer films were broken with negligible forces i.e. forces well below 1 N. The following tables show the effect of the particle size on the release rate. TABLE 6 Example 2 The following example discloses the stability of the coating according to the present invention. Cores of Diltiazem, 300 mg, were prepared as previously described and divided into 2 groups . The cores of group 1 were coated with the polymer Eudragit® and the cores of group 2 were coated with the polymer Kollicoat®. Both coatings were prepared with 71% by weight of KHT according to the present invention. The tablets were stability tested for 6 months and the results are shown in the following table 8. Table 8 **40°C ambient humidity As can be seen both groups demonstrated excellent sta- bilty properties even in such severe conditions as 6 months in 40 °C.

Claims: CLAIMS 1. A method for producing a controlled-release pharmaceutical preparation with a particle-containing coating comprising the steps of: a) preparing a drug-containing solid core; b) suspending a pore-forming agent having a balanced solubility in an aqueous dispersion of a film-forming, essentially water insoluble polymer in order to form a coating suspension having a predetermined amount of solid particles of the pore-forming agent suspended therein c) coating the solid core with the obtained suspension; and d) drying the coated tablet 2. A method according to claim 1, wherein the solubility of the pore-forming agent is below 100 mg/ml, preferably below 50 and most preferably below 30 mg/ml in the aqueous coating dispersion. 3. A method according to any one of the claims 1-2, wherein the mean particle size of the pore-forming agent is 0.1-500 μm, preferably is 0.5-100 μm and most preferably 1-25 μm. 4. A method according to any one of the claims 1-3, wherein the pore-forming agent is selected from a group consisting of potassium salts, calcium salts, magnesium salts, amino acids, week acids, carbohydrates, polymers with amino and/or acid functions or a composition wherein at least one of the components is selected from one of these groups . 5. A method according to any one of the claims 1-4, wherein the pore-forming agent is potassium bitartrate, creatine, aspargine, glutamine, aspartic acid, glutamic acid, leucin, neroleucine, inosine, isoleucine, magnesium citrate, magnesium phosphate, magnesium carbonate, magne- sium hydroxide, magnesium oxide or a composition wherein at least one component is selected from one of these substances . ω ω to to H LΠ o LΠ O in O LΠ 0 μ- Q rt CQ *- PJ 0 PJ φ CQ rt tr Φ rt μ- Ω CQ - PJ 0 0 Hj φ X μ- J 0 rt CQ -. PJ 0 rt μ- PJ Hj Hj * ; rf tr 3 μ- Ω CQ . PJ 0 rf μ- Pi Φ 1 pressants, anticoagulants, antidiarrhoetics, antihista- mines, antimalariels, antineoplastics, immunosuppres- sives, antiparkinsonians, antipsychotics, antiplatelets, diuretics, antihyperlipidics . 12. A method according to any one of the claims 1- 11, wherein the drug for the solid core is potassium chloride, theophylline, a theophylline salt, phenylpro- panolamine, sodium salicylate, choline theophyllinate, paracetamole, carbidopa, levodopa, diltiazem, enalapril, verapamil, naproxen, pseudoephedrin, nicorandil, oxybu- tuin, morphine, oxycodone or propranolol . 13. A method according to any one of the claims 1- 12, wherein the aqueous dispersion includes at most 20%, preferably at most 10% and most preferably at most 5% by weight of organic solvent. 14. A method according to any one of the claims 1- 12, wherein the obtained coated cores are cured with heat or moisture. 15. A method according to any one of the claims 1- 17, wherein the pore-former in the coating suspension is stabilized with one or more ionic, non-ionic or polymer surfactants . 16. A method according to any one of the claims 1-18, wherein the cdating polymer is plasticized. 17. A controlled-release pharmaceutical preparation including a drug-containing solid core having a coating thereon, said coating essentially consisting of a water insoluble polymer with a predetermined amount of particles of a water soluble, pore-forming agent dispersed therein, wherein the pore-forming agent is selected from the group consisting of potassium bitartrate, creatine, aspartic acid, glutamic acid and inosine. 18. A controlled-release pharmaceutical preparation including a drug-containing solid core having a coating thereon, said coating essentially consisting of a water insoluble polymer with a predetermined amount of particles of a water soluble, pore-forming agent dispersed *o o © o H U α. c- H v^ ■ C5 r- C5 0 t-- l O -n o LΠ O m o κ-i CM CM m

Inventors: FYHR PETER, KENDRUP JOHN, FYHR, PETER, KENDRUP, JOHN
Applicants: AMARIN DEV AB, FYHR PETER, KENDRUP JOHN, AMARIN DEVELOPMENT AB, FYHR, PETER, KENDRUP, JOHN
Application year: 2001
Main classification: A61K9
IPC codes: A61K9, A61K45, A61K47