PHARMACEUTICAL FORMULATION

Abstract: A solid, oral controlled release pharmaceutical dosage form has a water-soluble active ingredient dispersed in a matrix and releases the active ingredient at such a rate upon administration that the median tmax is 2.5 to 6 hours and the ratio of mean Cmax to mean plasma level of the active ingredient at 24 hours is in the range of 1.5 to 3.5.

Description: PHARMACEUTICAL FORMULATION This invention relates to a solid oral, controlled release pharmaceutical dosage form The literature is replete with examples of controlled release pharmaceutical preparations for oral usage PCT SE93/00642 describes an oral morphine preparation having essentially complete bioavailability and. for the major part of the dissolution, an essentiallv zero order and essentially pH independent release of morphine for a peπod of at least 8 hours, in the form of a tablet having a core containing morphine sulphate and a buffering agent, the tablet core being coated with a diffusion membrane comprising a terpolvmer of vinyl chloπde vinvlacetate and vinvlalcohol EP 0377518 describes a sustained release pellet composition containing a core element including at least one active ingredient of high solubility and a core coating for the core element which is partly soluble at a highly acidic pH to provide a slow rate of release of active ingredient and wherein the active ingredient is available for absoφtion at a relatively constant faster rate in the intestines over an extended period of time such that blood levels are maintained within the therapeutic range over an extended period of time A. typical embodiment in this patent publication is a morphine sulphate containing preparation suitable for twice a day dosing obtained by a process which compπses coating core seeds with the active ingredient and then coating the resulting core seeds with a controlled release coating material containing ethvl cellulose an acrylic co-polymer, a plasticiser and a detackifying agent using a solution of the atoresaid substances in an organic solvent PCT SE94 00264 describes controlled release preparations containing a salt of morphine comprising a number of core seeds coated with a barrier membrane In the Example a conventional granulation is carried out with morphine hydrochloride, lactose and microcrystalline cellulose The resulting morphine hydrochloride cores are then coated with a controlled release membrane containing hydroxypropyl methyl cellulose, ethvl cellulose and plasticisers using a solution of these substances in a mixed solvent of ethanol and methyl isobutvl ketone PCT/SE93/0025 describes a process for manufacturing sustained release pellets comprising pelletizing a mixture of a drug in finely divided form and a binder consisting of one or more water-insoluble wax-like binder substances with a melting point above 40°C, the pelletization being perfoπned by mechanically working the mixture in a high shear mixer under the input of a sufficient amount of energy for the binder to melt and pelletization to take place In a typical example in this patent publication paracetamol is pelletized using glycerol monostearate and optionally a lipophilic binder substance such as stearyl alcohol, triglyceride DS, Beeswax or microcrystalline wax, together with calcium hydrogen phosphate as a filler EP 0636370 describes a sustained release pharmaceutical formulation containing morphine which is suitable for administration on a once daily basis The dosage form is typically in the form of multiparticulates obtained bv mechanically working in a high shear mixer a pharmaceutically acceptable morphine salt and a hydrophobic fusible earner or diluent having a melting point from 35°C to 150°C and optionally a release control component comprising a water-soluble fusible material or a paniculate, soluble or insoluble organic or inorganic mateπal. at a speed and energy input which allows the carrier or diluent to melt or soften wherebv it forms agglomerates, breaking down the agglomerates to give controlled release panicles and optionally continuing mechanically working optionally with the addition of a low percentage of the carrier or diluent Embodiments are descπbed in EP 0636370 in which the mean Cmax obtained in a group of five health volunteers when dosed at 60 mg of morphine sulphate is approximately 8 ng' l and the W\ 0 value for morphine is approximately 8 6 hours The mean plasma curve includes a relatively high peak of about l Ong/ml at about 3 hours after dosing which tails off rapidly to reach a fairly stable, but declining level about 12 hours after dosing with the ratio of mean Cmax to the mean plasma level at 24 hours of about 4 5 According to the present invention there is provided a solid, oral, controlled release pharmaceutical dosage form which compπses a pharmaceutically active ingredient having a solubility in water of greater than lgm in 250ml water at 25°C dispersed in a controlled release matrix wherein the dosage form when tested bv the Ph Eur Basket method at 100 rpm 900 ml aqueous buffer (pH 6 5) containing 0 05° o w/w Polvsorbate 80 at 37°C has an essentially zero order rate of release of the pharmaceutically active ingredient over a peπod of 8 hours the amount of pharmaceutically active ingredient released over eight hours being in the range of 15% to 45% bv weight, and when tested in a group of at least five healthy humans the median tmax, based on blood sampling at half hourly intervals, is in the range of from 2 5 to 6 hours, and the ratio of mean Cmax to the mean plasma lev el at 24 hours is in the range of 1 5 to 3 5 Polvsorbate 80 is described in entry 7559 at page 1207 in Merck Index. Eleventh Edition 1989 published by Merck & Co Inc It is an oleate ester of sorbitol and its anhydrides copolymeπsed with approximately 200 moles of ethvlene oxide for each mole of sorbitol and sorbitol anhydrides A prefened dosage form in accordance with the invention has a median tmax in the range from 2 5 to 3 5 hours In a preferred embodiment the dosage form according to the present invention has a mean W\ 0 n the range from 15 to 35 hours, more preferablv 20 to 30 hours when tested in vivo as set forth above In preferred embodiments the matrix compπses an hydrophobic, fusible material having a melting point of greater than 40°C and mav also include a wicking agent which may be a hydrophilic, organic, polymeric, fusible substance or a paniculate soluble or insoluble inorganic mateπal In embodiments of the process of the invention described below it is believed the resulting matrix comprises an inner region which is a mixture comprising an hydrophobic fusible material and active ingredient and preferably wicking agent surrounded bv a contiguous, outer, mantle region comprising an hvdrophobic fusible mateπal have a reduced concentration of, or being substantially free from, said pharmaceutically active ingredient and wicking agent, though the invention is not limited to this theorv The pharmaceutically active ingredient is preferably present in an amount suitable for twice or once a day dosing The preferred active ingredient is morphine or a pharmaceutically acceptable salt of morphine, preferablv morphine sulphate or morphine hvdrochloπde and is preferably present in an amount suitable for once a dav dosing The dosage forms mav preferablv contain 30 to 400 mg of morphine as pharmaceutically acceptable salt The dosage form of the invention is conveniently in the form of a tablet or a capsule containing multiparticulates Although morphine and pharmaceutically acceptable morphine salts have been mentioned above as prefened active ingredients, other suitable water soluble active ingredients include hydromorphone hydrochloride, diamorphine hydrochloride tramadol hydrochloride and dihydrocodeine tartrate Preferably the weight ratio of hvdrophobic, fusible mateπal to wicking agent in the matπx or inner region thereof is in the range from 8 1 to 16 1 preferablv 8 1 to 12 1 Suitably the weight ratio of hydrophobic, fusible material in the said mixture to hvdrophobic, fusible material in the mantle region is in the range of from 3 1 to 12 1 Suitable hydrophobic, fusible materials are natural or synthetic waxes, oils, fattv acid glyceπdes or other esters for example hvdrogenated vegetable oil or castor oil and suitable hydrophilic, organic, fusible wicking agents include polyethylene glycols (PEGs) of various molecular weights e g 1,000 to 20,000 preferably 4,000 to 10,000 and suitable particulate inorganic wicking agents include dicalcium phosphate and lactose It is prefened to use an hydrophilic fusible organic polymeric as wicking agent The dosage forms of the present invention have a significantly lower Cmax and greater W so than dosage forms made according to the method described in EP 636370 whilst surprisingly retaining an advantageously short median tmax of 2 5 to 6 hours Dosage forms of the present invention can be prepared by a process comprising - (a) mechanically working in a high shear mixer a mixture of hydrophobic. fusible binder and a minor amount of an organic, fusible, polymeric material which in the finished dosage form is capable of functioning as a wicking agent at a speed and temperature at which the binder melts or softens and the mixture forms agglomerates; (b) extruding the agglomerates whereby the extrudate is obtained as extruded pieces or an elongate extrudate is formed into pieces; (c) continuing mechanically working the pieces in a high shear mixer suitably until particles of reproducible in vitro release rate when tested according to the iri vitro method set forth above have been achieved; and (d) continuing mechanically working with additional binder material at a temperature and speed at which the additional binder melts or softens and binds with the particles. A preferred process uses identical hydrophobic, fusible material in stage (d) as in stage (a) Preferably in stage (a) the weight ratio of hydrophobic, fusible material to wicking agent, preferably hydrophobic, organic, polymeric wicking agent, used is in the range from 8 1 to 16 1 preferably 8: 1 to 12.1. Preferably the weight ratio of hydrophobic, fusible material used in stage (a) to hydrophobic, fusible material use in stage (d) is in the range from 3 1 to 12.1 preferably 3 1 to 7.1. The resulting multipaπiculates may be sieved or otherwise size selected and filled into capsules e.g. hard gelatine capsules, or may be compressed into tablets. Usually the particles are of a size 0.5 mm to 3.0 mm and a spherical or spheroidal. The higher shear mixer may be one conventionally used in the pharmaceutical formulation art and we have found satisfactory results can be achieved using a Collette Gral 75 or equivalent mixer Generally in stage (a) the mixture is processed until a bed temperature above 40°C is achieved and the mixture softens but does not melt and the resulting mixture acquires a cohesive granular texture, with particles ranges from 0.5 to 3.0 mm to fine powder in case of non-aggregated material. The mixture may be processed until it has the appearance of agglomerates which , upon cooling below 40°C have structural integrity and resistance to crushing between the fingers. At this stage the agglomerates are of an inegular size, shape and appearance. The resulting mass is then extruded. Extrusion may be canied out by passing the agglomerates through a conventional extruder e g a Caleva extruder An extruder may be used fitted with gears with suitably sized holes to provide pieces of desired size Usually the extrusion is though orifices having a diameter of about 0 25 mm to 1 5 mm eg 0 5 mm or 1 0 mm The length of the extrudate pieces mav be eg 0 5 to 1 5 cm eg 1 0 cm The preparation avoids the complicated forms of prior art preparations in that it does not require the use of controlled release coatings or buffers, whilst at the same time enabling dosing at only twice preferably once a day and without large fluctuations in blood plasma levels during the dosing intervals Example 1 The bowl of a Collette Gral 10 was preheated to a jacket temperature of 61 °C and allowed to stabilise 540 5g of morphine sulphate 36g of polyethylene glvcol 6000 and 343 2g of hvdrogenated vegetable oil were placed in the pre-heated jacketed bowl and left to warm with no mixing for about 4 minutes The machine was then run for about 20 to 25 minutes with mixer and chopper blades running at 425 rpm and setting 1 respectively The resulting granules/agglomerates were then immediately removed and passed through a Caleva extruder fitted with 1mm hole gears The extruded pieces were placed in the bowl of the Collette Gral 10 which had been preheated to a jacket temperature of 61°C and left with no mixing for 4 minutes Processing was then carried out as follows - (a) for 4 minutes at mixer speed 100 φm and chopper speed setting 1 (b) for 4 minutes at mixer speed 200 φm, chopper setting 1 and jacket temperature 58°C, and (c) for 9 minutes at mixer speed 400 φm, chopper setting 1 and jacket temperature 55°C (d) 73g of hvdrogenated vegetable oil were then added and processing was continued under the same conditions for a further minute The resulting multiparticulates were immediately passed through a sieve (0 5 to 2 0mm) and the 0 5-2 0mm fraction retained The retained multiparticulates were mixed with minor amounts of talc and magnesium stearate and encapsulated in hard gelatine capsules so that each capsule contained the following constituents mg Moφhine Sulphate BP 60 00 Hydrogenated vegetable oil NT 46 10 Polyethylene glycol 6000 Ph Eur 4 00 Talc Ph Eur 0 55 Magnesium Stearate Ph Eur 0 33 Example 2 Example 1 was repeated but using 526g of moφhine sulphate, 35g of polyethylene glycol 6000, and 334g hydrogenated vegetable oil in the initial processing and subsequently adding 88g of hydrogenated vegetable oil in stage (d) Capsules were obtained containing multiparticulates having the following constituents - mg/capsule Morphine sulphate BP 60 00 Hydrogenated vegetable oil NF 48 10 Polyethylene glycol 600 Ph Eur 4 0 Talc Ph Eur 0 56 Magnesium stearate Ph Eur 0 33 REFERENCE EXAMPLE 1 The multiparticulates obtained in Examples 1 and 2 were tested using the Ph Eur Basket method at 100 φm in 900 ml aqueous buffer (pH 6 5) containing 0 05% w/v Polysorbate 80 at 37°C and the release rates of moφhine are shown in Table 1 REFERENCE EXAMPLE 2 The capsules obtained in Examples 1 and 2 and. by way of comparison, capsules obtained according to EP-A-636370 were tested in a single dose study in five healthy volunteers and blood samples were taken every half hour. The results are as shown in the following tables 2, 3 and 4 TABLE 2 - CAPSULE ACCORDING TO EP-A 636370 CONTAINING 60MG MORPHINE SULPHATE Vol Cmax (ng/ml) tmax (h) W50 (h) C24 (ng ml) Cmax/C24 1 9 42 5 7 25 2 63 3 58 "> 1 50 4 5 47 1 59 7 23 J - - - - - 4 1 1 72 5 19 2 45 4 78 5 7 12 j 15 68 2 77 2 57 6 1 1 33 3 4 01 2 38 4 76 Mean 10 22 7 52 2 36 4 58 sd 1 96 4 71 0 46 1 74 Median 3 Range 3-5 TABLE 3 - CAPSULE ACCORDING TO EXAMPLE 1 Vol Cmax (ng/ml) | tmax (H) W50 (h) C24 (ng/ml) Cmax/C24 1 5 32 3 43 30 3 12 1 71 2 4 55 5 34 88 2 33 1 95 3 87 -> 52 38 1 84 2 10 4 8 37 3 19 23 3 58 2 34 5 8 24 3 5 37 2 89 2 85 6 5 90 -> _> 12 98 2 90 2 03 Mean 6 04 28 02 2 78 2 16 sd 1 88 18 39 0 61 0 39 Median 3 Range 3-5 TABLE 4 - CAPSULE ACCORDING TO EXAMPLE 2 Vol Cmax (ng/ml) tmax (H) W50 (h) C24 (ng/ml) Cmax/C24 1 4 72 13 33 45 2 98 1 58 2 3 93 3 36 84 2 50 1 57 - - - - - - 4 -> 6 91 20 63 3 41 2 03 5 5 90 3 24 93 3 08 1 92 6 6 31 3 13 15 2 60 2 43 Mean 5 55 25 80 2 91 1 91 sd 1 21 9 59 0 37 0 36 Median 3 Range 3- 13

Claims: CLAIMS A solid, oral, controlled release pharmaceutical dosage form which comprises a pharmaceutically active ingredient having a solubility in water of greater than lgm in 250ml water at 25°C dispersed in a matrix and wherein the dosage form when tested by the Ph Eur Basket method at 100 rpm 900 ml aqueous buffer (pH 6 5) containing 0 05% w/w Polysorbate 80 at 37°C has an essentially zero order rate of release of the pharmaceutically active ingredient over a period of 8 hours, the amount of pharmaceutically active ingredient released over eight hours being in the range of 15% to 45%, and when tested in a group of at least five healthy humans the median tmax, based on blood sampling at half hourly intervals, is in the range of from 2 5 to 6 hours, and the ratio of mean Cmax to the mean plasma level at 24 hours is in the range of 1 5 to 3 5 A pharmaceutical dosage form according to claim 1, wherein the median tmax is in the range from 2 5 to 3 5 hours A pharmaceutical dosage foπn, according to any one of the preceding claims which has a W 50 in the range from 15 to 35 hours, preferably from 20 to 30 hours, when tested in vivo as set forth in claim 1 A pharmaceutical dosage form according to claim 1, 2 or 3, wherein the matrix comprises a mixture of an hydrophobic, fusible material having a melting point of greater than 40°C and a hydrophilic, organic , polymeric fusible wicking agent A pharmaceutical dosage fonn according to any one of claim 4 wherein the weight ratio of hydrophobic fusible material to hydrophilic, organic polymeπc wicking agent in the said mixture is in the range from 8 1 to 16 1 A pharmaceutical dosage form according to any one of the preceding claims, in which the pharmaceutically active ingredient is a pharmaceutically acceptable salt of moφhine, preferably morphine sulphate or morphine hydrochloride A pharmaceutical dosage form according to claim 5, which is suitable for once a day dosing. A pharmaceutical dosage form according to any one of the preceding claims, in the form of a tablet or a capsule containing multiparticulates A process for preparing a dosage form according to any one of the preceeding claims comprising - (a) mechanically working in a high shear mixer a mixture of hydrophobic. fusible binder and a minor amount of an organic, fusible, polymeric material which in the finished dosage form is capable of functioning as a wicking agent at a speed and temperature at which the binder melts or softens and the mixture forms agglomerates; (b) extruding the agglomerates whereby the extrudate is obtained as extruded pieces or an elongate extrudate is formed into pieces; (c) continuing mechanically working the pieces in a high shear mixer; and (d) continuing mechanically working with additional binder material at a temperature and speed at which the additional binder melts or softens 10 A process according to claim 8, wherein in stage (d) the additional binder melts or softens and binds with the particles 1 1 A solid, oral, controlled release pharmaceutical dosage form which comprises a pharmaceutically active ingredient having a solubility in water of greater than lgm in 250ml water at 25°C dispersed in a matrix, the dosage form being obtainable by a process as defined in claim 9 or claim 10.

Inventors: KNOTT TREVOR JOHN, LESLIE STEWART THOMAS, MALKOWSKA SANDRA THERESE ANTOI, MILLER RONALD BROWN, MOHAMMAD HASSAN, PRATER DEREK ALLAN, KNOTT, TREVOR, JOHN, LESLIE, STEWART, THOMAS, MALKOWSKA, SANDRA, THERESE, ANTOINETTE, MILLER, RONALD, BROWN, MOHAMMAD, HASSAN, PRATER, DEREK, ALLAN
Applicants: EURO CELTIQUE SA, KNOTT TREVOR JOHN, LESLIE STEWART THOMAS, MALKOWSKA SANDRA THERESE ANTOI, MILLER RONALD BROWN, MOHAMMAD HASSAN, PRATER DEREK ALLAN, EURO-CELTIQUE S.A., KNOTT, TREVOR, JOHN, LESLIE, STEWART, THOMAS, MALKOWSKA, SANDRA, THERESE, ANTOINETTE, MILLER, RONALD, BROWN, MOHAMMAD, HASSAN, PRATER, DEREK, ALLAN
Application year: 1996
Main classification: A61K31
IPC codes: A61K9, A61K31