PCT. upon receipt of that report

Transcription

1 (12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (43) International Publication Date (10) International Publication Number 12 June 2008 ( ) PCT WO 2008/ A2 (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every A61K 31/4422 ( ) A61K 9/28 ( ) kind of national protection available): AE, AG, AL, AM, AT,AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ, CA, CH, (21) International Application Number: CN, CO, CR, CU, CZ, DE, DK, DM, DO, DZ, EC, EE, EG, PCT/IN2007/ ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN, KP, KR, KZ, LA, LC, LK, (22) International Filing Date: LR, LS, LT, LU, LY, MA, MD, ME, MG, MK, MN, MW, 5 December 2007 ( ) MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PG, PH, PL, PT, RO, RS, RU, SC, SD, SE, SG, SK, SL, SM, SV, SY, (25) Filing Language: English TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW (26) Publication Language: English (84) Designated States (unless otherwise indicated, for every (30) Priority Data: kind of regional protection available): ARIPO (BW, GH, 2004/MUM/ December 2006 ( ) IN GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), (71) Applicant (for all designated States except US): TOR European (AT,BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, RENT PHARMACEUTICALS LIMITED [IN/IN] ; Tor FR, GB, GR, HU, IE, IS, IT, LT, LU, LV,MC, MT, NL, PL, rent House, Off Ashram Road,, Near Dinesh Hall, Gujarat, PT, RO, SE, SI, SK, TR), OAPI (BF, BJ, CF, CG, CI, CM, Ahmedabad (IN). GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG). (72) Inventors; and Declarations under Rule 4.17: (75) Inventors/Applicants (for US only): GUNUPATI, as to applicant's entitlement to applyfor and be granted a Jyothi, Lakshmi [IN/IN]; Torrent Pharmaceuticals Lim patent (Rule 4.17(U)) ited, Torrent Research Centre,, Dist. Gandhinagar, Gujarat, as to the applicant's entitlement to claim the priority of the Bhat (IN). NANDA, Nagesh [IN/IN]; Torrent earlier application (Rule 4.17(Ui)) Pharmaceuticals Limited, Torrent Research Centre,, Dist. of inventorship (Rule 4.17(iv)) Gandhinagar, Gujarat, Bhat (IN). Published: (74) Agents: MAJUMDAR, Subhatosh et al; S. Majumdar & without international search report and to be republished Co., 5, Harish Mukherjee Road, Calcutta (IN). upon receipt of that report (54) Title: STABLE LERCANIDIPINE FORMULATION (57) Abstract: The present invention relates to stable solid oral dosage form of lercanidipine by using a process of preparation of adsorbates. The invention further relates to lercanidipine adsorbates that are obtainable by said process, as well as pharmaceutical formulations prepared while employing said lercanidipine adsorbates.

2 STABLE LERCANIDIPINE FORMULATION TECHNICAL FIELD OF THE INVENTION The present invention relates to stable solid oral dosage form of lercanidipine by using a process of preparation of adsorbates. The invention further relates to lercanidipine adsorbates that are obtainable by said process, as well as pharmaceutical formulations prepared while employing said lercanidipine adsorbates. BACKGROUND OF THE INVENTION Lercanidipine hydrochloride, i.e., (methyl 1, 1, N-trimethyl-N-(3, 3-diphenylpropyl)-2- aminoethyl 1, 4-dihydro-2, 6-dimethyl-4-(3-nitrophenyl) pyridine-3, 5-dicarboxylate), hydrochloride having the formula (I) is disclosed herewith. Formula I Lercanidipine hydrochloride is an antagonist of type-l calcium channels, and has been found to be very active as an antihypertensive and thus useful agent for the treatment of angina and coronary diseases. Its mechanism of antihypertensive activity is attributed to a direct relaxant effect on vascular smooth muscle, which lowers total peripheral resistance.

3 Lercanidipine hydrochloride belongs to dihydropyridine group. The dihydropyridine have been classified into first, second and third generation. Table 1: Present classification of dihydropyridines The pharmacokinetics of lercanidipine is unique in comparison to other dihydropyridines. Lercanidipine is an example of a lipophilic and vasoselective dihydropyridine calcium channel blocker, owing to the lipophilic character of such compounds, considerable concentration occurs in lipid-containing membrane depots. The drug thus concentrated is

4 slowly released from these depots and, subsequently, reach their targets, the L-type calcium channels. This phenomenon explains both the slow onset and the long duration of action of the drug. Owing to the slow onset of action reflex tachycardia is virtually absent. The long duration of action allows satisfactory control of blood pressure in hypertensive patients by means of a single daily dose. It is an effective vasodilator / antihypertensive drug, with a slow onset and long duration of action, which is associated with neither reflex tachycardia nor cardio depressant activity. It has a high affinity for and competitively antagonizes the dihyropyridine subunit of the L-type calcium channel. Lercanidipine hydrochloride is disclosed in US 4,705,797. Lercanidipine has been approved for the treatment of hypertension and has been marketed in several European countries under the under the trade name of Carmen (Manufacturer: Berlin Chemie) or Corifeo (Manufacturer: UCB) or Zanidip (Manufacturer: Recordati). Lercanidipine and its salts, such as the hydrochloride salt, are practically insoluble in water. Lercanidipine also shows low permeability. Also, when administered to patients, lercanidipine displays high first pass metabolism as a result of its being a substrate for CYP3A4. The combination of low water solubility, low permeability and high first pass metabolism results in low and highly variable bioavailability and thus creating a challenge to develop immediate release composition. Also, it is known from the prior art like, EP A l and EP Bl that Lercanidipine hydrochloride shows polymorphism and available as an amorphous form, several crystalline forms and as a mixture of crystalline form with amorphous form. The polymorph (crystalline form or amorphous form) of the active ingredient in a dosage form may play a significant role in the behavior of the drug in the dosage form, once taken orally, and may in turn influence its therapeutical effect. For example polymorphic state of the drug may modify the dissolution and thus influence absorption and the therapeutic effect of the drug. In such a case it is very important that the polymorphic form of the molecule

5 remains constant during the process of preparing formulation and its shelf life in order to ensure the consistent therapeutical activity of the drug. Any polymorphic form either crystalline or amorphous form of the drug can be used in the present invention. US discloses sustained release capsule or tablet formulation comprising an adsorbate of a mixture of a pharmaceutically useful dihydropyridine like Felodipine, Nicardipine, Nitrendipine, Nimodipine, Nislodipine and a polyvinylpyrrolidone having an average-molecular weight greater than 55,000 adsorbed on a cross-linked polyvinylpyrrolidone and blended with a polymer or mixture of polymers which gel in the presence of water, the amount of said polymer or polymers being effective to produce the desired sustained release effect. This patent employs specifically the process of adsorbing dihydropyridine with polyvinylpyrrolidone over crosspovidone for preparing sustained release formulation. WO A2 discloses a controlled release pharmaceutical composition comprising ; lercanidipine dissolved or dispersed in a solid vehicle at ambient temperature, thus forming a solid dispersion, achieves delayed release of lercanidipine over an extended period of time. WO A l discloses modified release pharmaceutical composition comprising lercanidipine dissolved or suspended in a waxy substance comprising a polyalcohol fatty acid ester, the solution being contained within a pharmaceutically acceptable capsule. US A l discloses a modified release composition containing the low solubility and permeability drug, lercanidipine that provides therapeutically effective plasma concentrations of lercanidipine for 24 hours. The modified release composition releases pulses of lercanidipine based on the ph of the use environment. US A l discloses modified release composition containing the low permeability and poor solubility drug, lercanidipine that provides therapeutically effective plasma concentrations of lercanidipine for a period of about 20 to about 25 hours.

6 All the above mention prior art teaches about sustained release, controlled release or modified release formulation of lercanidipine or other dihydropyridines. US discloses rapidly absorbable composition of dihydropyridine selected from nifedipine, nimodipine, nitrendipine, nisoldipine and felodipine, specifically using polyvinylpyrrolidone with an average molecular weight of 15,000 to 50,000 and crosslinked insoluble polyvinylpyrrolidone. This patent employs specifically the process of adsorbing dihydropyridine with polyvinylpyrrolidone over crosspovidone for preparing immediate release formulation. US A l discloses an immediate release composition for lercanidipine. The immediate release composition comprises a core; a first layer, comprising lercanidipine, a surfactant and a binder, and optionally, a second layer comprising a film coating. The surfactant plays an important role in immediate release composition. The special equipment like fluidized bed coater (GPGC3, Glatt Air Technique, Ramsey, NJ) manufacturing of the formulation. is required for the. WO A l discloses a substantially pure amorphous lercanidipine hydrochloride having a purity of at least 95% pure, and further provides information about methods of preparing substantially pure amorphous lercanidipine, its immediate release and modified release compositions, as well as methods of providing rapid relief from hypertension by administering the substantially pure amorphous lercanidipine hydrochloride. No detail information is provided in the patent application for manufacturing pharmaceutical composition of the amorphous lercanidipine hydrochloride w.r.t achieving similar blood plasma profile to that of crystalline Lercanidipine. It only describes that the AUC/Cmax are lower and Tmax is between 45 to 75 minutes when amorphous lercanidipine hydrochloride is used against crystalline lercanidipine hydrochloride. It does not teach how to make a bioequivalent formulation to the marketed Lercanidipine formulation. It further teaches to make modified release formulation of amorphous lercanidipine hydrochloride using waxy substance. Hence, there is a need to make a formulation wherein the amorphous form does

7 not changes into crystalline form and is still bioequivalent to the marketed Lercanidipine formulation. Inventors of the present invention surprisingly found a simple and easy to manufacture, stable solid oral dosage form that provides desired dissolution profile of lercanidipine and additionally retaining the same polymorphic form. SUMMARY OF THE INVENTION The first embodiment of the present invention provides Lercanidipine adsorbates. Another embodiment of present invention provides stable solid oral dosage form of lercanidipine obtained by process of preparation of adsorbates. Yet another embodiment of the present invention is an immediate release stable solid oral dosage form of lercanidipine obtained by process of preparation of adsorbates of lercanidipine. Another embodiment of the present invention is an immediate release stable solid oral dosage. form of lercanidipine obtained by process of preparation of adsorbates of lercanidipine which is free from surfactants. Another embodiment of the present invention is an immediate release stable solid oral uncoated tablet dosage form of lercanidipine obtained by a process of preparation of adsorbates of lercanidipine, which is free from surfactants. One embodiment of the present invention is an immediate release solid oral dosage form of lercanidipine obtained by a process of preparation of adsorbates of lercanidipine which remains stable with respect to physical, chemical or polymorphic changes. Another embodiment of the present invention is to provide a process of preparation of adsorbates of lercanidipine.

8 Another embodiment of the present invention is to provide a process of preparation of adsorbates of lercanidipine according to which lercanidipine is dissolved in at least one solvent preferably organic solvent, and this solution is adsorbed over adsorbing materials, the solvent is then further removed which can be achieved by drying, immediately after adsorption or at later stages. Another embodiment of the present invention is lercanidipine adsorbates that are obtainable by said process, and the formulations prepared while employing said lercanidipine adsorbates, which may contain further pharmaceutically acceptable excipients and can be converted into the formulation having desired release profile. Tablets may be produced by direct compression or wet granulation or dry granulation. BRIEF DESCRIPTION OF THE DRAWING Figure 1: Comparative XRPD (X-Ray Powder Diffraction) data of lercanidipine. hydrochloride, placebo tablet, initial tablet, tablet at 1 month 40 C-75% relative humidity and tablet at 2 month 40 C-75% relative humidity. Figure-2: shows the comparative dissolution profile in 0.0 IN HCl. Figure-3: shows the comparative dissolution profile in ph 3.0 buffer. DETAILED DESCRIPTION OF THE INVENTION: The term "immediate release" as used herein refers to the release of an active ingredient such as a drug from a pharmaceutical composition, formulation or dosage form in which the active ingredient is released according to a desired dissolution profile (Not less than 75% in thirty minutes). The term "dosage form" or "solid oral dosage form" or "pharmaceutical composition" or "formulation" as used in this specification and the claims refer to physically discrete units to be administered in single or multiple dosages, each unit containing a predetermined quantity of active material optionally in association with the required excipients. The quantity of

9 active material is that calculated to produce the desired therapeutic effect upon administration of one or more of such units. The dosage form used herein selected from tablets, capsule, sachets, pellets, beads, microspheres, microcapsules, pills, powders, lozenges, or granules. The term "lercanidipine" or "drug" or "active ingredient" includes lercanidipine as well its pharmaceutically acceptable salt, solvates or hydrates. Additionally, lercanidipine may be present either in crystalline and / or amorphous forms. The term "stable" as used herein refers to dosage form which is physically, chemically or polymorphically stable. The dosage form according to present invention may remain physically stable that is there are no substantial change with respect to physical attributes like colour etc. The dosage form according to present invention may remain polymorphically stable that is the polymorph (crystalline or amorphous) in the dosage form does not rearranges into another form upon storage for atleast 2 months at 4 O 0 C and 75% relative humidity. The dosage form according to present invention may remain chemically stable that is the total impurities in the dosage form is not more than 1.5 % upon storage for atleast 2 months at 40 C and 75% relative humidity, preferably the total impurities in the dosage form is not more than 1.0 % upon storage for atleast 2 months at 40 C and 75% relative humidity, more preferably the total impurities in the dosage form is not more than 0.5 % upon storage for atleast 2 months at 40 0 C and 75% relative humidity. The term "adsorbates" or "lercanidipine adsorbates" as used herein refers to particles of lercanidipine that are closely associated with adsorbing materials. However, it is not essential that all the particles of lercanidipine may actually be in contact with adsorbing materials. The term "Amorphous" as used herein refers to solid-state particles that lack a regular crystalline structure and as a result give a diffuse, i.e., non-distinctive, x-ray powder diffraction pattern.

10 The term "Crystalline" as used herein refers to solid-state particles having a regular ordered structure, which, in contrast to amorphous material, give a distinctive x-ray powder diffraction pattern with defined peaks. The dosage form of the present invention comprises lercanidipine in a range of about 2 mg to 80 mg. Preferably may contain 5 mg to 40 mg. more preferably dosage form may contain 5 mg to 20 mg. The present invention relates to lercanidipine adsorbates and solid oral pharmaceutical formulation comprising lercanidipine adsorbates and one or more pharmaceutically acceptable excipient. The present invention further discloses a process of preparation of adsorbates of lercanidipine according to which lercanidipine is dissolved in at least one solvent preferably organic solvent, and this solution is adsorbed over adsorbing materials, the solvent is then further removed which can more particularly be achieved by drying, immediately after adsorption or at later stages. Also, to this organic solution of the active ingredient, a pharmaceutically acceptable ingredient that is insoluble or poorly soluble can be added as the adsorbing material, well wetted, and the solvent is removed by drying. The drying process can be promoted by temperature, applying a vacuum, sublimation drying for instance, or also by spray drying. Preferably, it is conducted in such a way that appropriate mechanical action (e.g., rotating, tumbling, or stirring motion) yields a uniform distribution. Adsorbates prepared by the process described can be employed directly in further processing to drug formulations such as tablets, capsules, pellets, or granules. The adsorbates can also be prepared in but not limited to spray dryer, fluid bed processor (top spray / bottom spray / coaxial spray) or rapid mixer granulator.

11 The solvent, more preferably organic solvent in which the active ingredient will be dissolved are suitable for the process according to the invention, for the preparation of lercanidipine adsorbates. The organic solvents are selected from the group of lower alkanols with one to four carbon atoms, the group of ethers, the group of esters, the group of aliphatic ketones, and the group of halogenated hydrocarbons, as well as mixtures of said solvents. Methanol, ethanol, isopropanol, n-propanol, acetone and other solvents such as ethyl acetate, methyl ethyl ketone, di-isopropyl ether, MTBE (methyl tert-butyl ether), dichloromethane, acetone, hexane, an acetone/water mixture, an ethyl acetate/hexane mixture, a dichloromethane/ethyl acetate mixture, as well as further mixtures of said solvents thereof. According to the present invention, those pharmaceutically acceptable excipients are used as adsorbing materials which are appropriate for desired release of the active ingredient, such as celluloses and cellulose derivatives, dicalcium phosphate, lactose, maltodextrin, starch and starch derivatives, colloidal silicon dioxide, calcium silicate, Neusilin (magnesium aluminometasilicate) cyclodextrins, polydextroses, various coprocessed excipients like Microcelac (75% Lactose monohydrafe & 25% microcrystalline cellulose), Prosolv SMCC (Silicified microcrystalline cellulose), Starlac (Starch - Lactose compound) or mixtures of said substances. Microcrystalline cellulose, lactose, mannitol and other sugar alcohols are preferred according to the invention. For an improvement of the flow properties, additives such as excipients containing silica can be used. Also, the desired dissolution profile can be obtained by modifying the surface area of the adsorbing materials. The ratio of pharmaceutical active ingredient to adsorbing material according to the invention is in the range from 1:0. 1 to 1:20, a range from 1:1 to 1:10 being particularly preferred. The excipients present in the pharmaceutical composition according to the invention can be diluents such as microcrystalline cellulose, powdered cellulose, lactose, compressible sugar, fructose, dextrates, other sugars such as mannitol, sorbitol, lactitol, sacharose or a mixture thereof, silicified microcrystalline cellulose, calcium hydrogen phosphate, starches, calcium carbonate, calcium lactate or mixtures thereof and if required, other diluents known to person

12 skilled in the art. Preferably, the excipients include at least one diluent, selected from microcrystalline cellulose and starch. The pharmaceutical composition according to the invention can also comprise binders, such as polyvinyl pyrrolidone, microcrystalline cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, low- substituted hydroxypropyl cellulose, hydroxypropylmethyl cellulose or other cellulose ethers, starch, pregelatinised starch, or polymethacrylate or mixtures of binders and if required, other binders known to person skilled in the art. It is preferred that the excipients include at least one binder selected from povidone and starch. Further, disintegrants can also be present, such as starch, e.g. pregelatinised starch, corn starch or other starch derivatives, sodium starch glycolate, microcrystalline cellulose, carboxymethylcellulose sodium, polacrilin potassium, low-substituted hydroxypropyl cellulose or mixtures thereof and if required, other disintegrants known to person skilled in the art. It is preferred that the excipients include at least one disintegrant selected form starch, sodium starch glycolate and low-substituted hydroxypropyl cellulose. The disintegrants can be added to the other excipients according to the process used in the state of the art, either in the process of granulating and/or in the preparation of the compression mixture. Further, lubricants can also be present as excipients, such as stearic acid, magnesium stearate, calcium stearate, sodium lauryl sulphate, hydrogenated vegetable oil, hydrogenated castor oil, sodium stearyl fumarate, talc, or macrogol or mixtures thereof and if required, other lubricants known to person skilled in the art It is preferred that the excipients include at least one lubricant selected from sodium stearyl fumarate, talc and magnesium stearate. Beyond that, all other excipients known to those skilled in the art, such as lubricants, disintegration aids, wetting agents, agents to improve the flow behavior, other additives, stabilizers, as well as flavors, pigments, and dyes, can be used to prepare the drug

13 formulations according to the invention. The proportions pharmaceutically acceptable excipients can be used, which are known to the person skilled in the art. According to the invention, a process has now been found which, starting from a solution of lercanidipine in an organic solvent, leads to adsorbates of the active ingredient that can be processed directly to the drug formulation. The solid oral dosage form of the present invention may be prepared by following preffered steps: 1. Sift the adsorbing materials through 40# mesh and mix thoroughly. 2. Dissolve drug in suitable solvent. Adsorb the drug solution onto the blend of step Optionally dissolve binder in suitable solvent and add over the blend from step Dry the wet granules from step 2 or from step 3 and sift the dried granules through 40# mesh. 5. Sift the lubricants and optionally other pharmaceutically acceptable excipient through suitable mesh and mix this with dried blend of step Compress the blend from step-5 using suitable punches or fill into the capsules. The tablet dosage form may be manufactured by direct compression or wet granulation or dry granulation. Optionally, the adsorbates or drug formulations thus obtained can be further provided with coatings of pharmaceutical polymethacrylates such as Eudragit, Kollicoat SR 3OD (polyvinylacetate aqueous dispersion), methyl celluloses, ethyl celluloses, hydroxypropyl methyl celluloses, cellulose acetate phthalates and/or shellac in order to fill a specific application, e.g., controlled release of the active ingredient and/or taste masking or aesthetic purpose or durability purpose. Those skilled in the art of pharmaceutics have sufficient technical possibilities to do this.

14 EXAMPLES Without further elaboration, it is believed that one skilled in the art can, using the preceding description, practice the present invention to its fullest extent. The following detailed examples are to be construed as merely illustrative, and not limitations of the preceding disclosure in any way whatsoever: Table 2 * Does not remain in finished product except in traces.

15 Process 1. Microcrystalline cellulose, Maize starch, Sodium starch glycolate, and Colloidal silicon dioxide were sifted through 40# mesh and mixed thoroughly. 2. Lercanidipine hydrochloride was dissolved in Methanol. The drug solution was adsorbed onto the blend of step Povidone was dissolved in Methanol and added over the blend from step-2 (B.No:001) 4. The wet granules from step 2 (B.No:002) or from step 3 (B.No:001) were dried and the dried granules were sifted through 40# mesh. 5. Sodium Stearyl Fumarate (B.No:002) or a mixture of Colloidal Silicon Dioxide and Sodium Stearyl Fumarate (B.No.001) were sifted through 40# mesh and this was mixed with dried blend of step The blend from step-5 was compressed using suitable punches. 7. The compressed tablet was film coated. Dissolution profile The dissolution of the present invention was determined by following method: Table 3 Instrument : USP Apparatus II RPM : 50 Temperature : 37 C Dissolution Medium : a) 0.01 N HCl IOOO m L b) 3.O ph buffer, 100O ml,

16 The dissolution profiles of the tablets prepared as per B.No:001, 002 and Carmen Tablet, market sample of Lercanidipine Tablets (Manufacturer: Berlin Chemie) are given in the table below: Table 4 Stability Data: The stability data of Lercanidipine hydrochloride tablets manufactured as per B.No:001 packed in PVC blister is as below: Table 5

17 Testing the tablets by X-ray diffraction in order to evaluate the polymorphism of the drug is a difficult task. Lercanidipine hydrochloride tablet contains many pharmaceutically acceptable excipients. Being crystalline compounds these excipients do have X-ray powder diffraction pattern. This pattern has to be subtracted from the total pattern in order to see the peaks that originate from lercanidipine hydrochloride. The fact that lercanidipine hydrochloride itself is only a small part of the formulation makes it even harder. Moreover, the X-ray powder diffraction patterns of the tablets prepared as per instant invention and the placebo are similar. The absence of extra X-ray powder diffraction peaks in the tablet pattern at initial stage and accelerated stability conditions ( 1 month and 2 month 40 C -75% relative humidity) indicates that there is no contribution from the lercanidipine hydrochloride in the tablet, showing it remains in amorphous state. Pharmaceutical composition of present invention using amorphous lercanidipine hydrochloride was found to be bio-equivalent when compared against Carmen (20mg).

18 CLAIMS 1. Lercanidipine adsorbate in substantially amorphous form. 2. An immediate release stable solid oral dosage form comprising lercanidipine adsorbate of claim 1 and one or more pharmaceutically acceptable excipients. 3. An immediate release stable solid oral dosage form of lercanidipine or its pharmaceutically acceptable salt obtained by process of preparation of adsorbates of lercanidipine in substantially amorphous form. 4. An immediate release stable solid oral dosage form of lercanidipine or its pharmaceutically acceptable salt according to claim 2 or 3, wherein the solid oral dosage form is in the form of tablet or capsule. 5. The immediate release stable solid oral dosage form according to claim 2 or 3, wherein the adsorbate of lercanidipine is free from surfactants. 6. The immediate release stable solid oral dosage form of lercanidipine hydrochloride according to claim 2 or 3, wherein lercanidipine hydrochloride is in amorphous form. 7. A process for the preparation of adsorbates of lercanidipine comprises a) dissolving lercanidipine in at least one solvent b) adsorbing drug solution over adsorbing materials and c) removing the solvent immediately after adsorption or at later stages. 8. The process according to claim 7, wherein a solvent is selected from the group of lower alkanols with one to four carbon atoms, the group of ethers, the group of esters, the group of aliphatic ketones, and the group of halogenated hydrocarbons, as well as mixtures of said solvents.

19 9. The process according to claim 7, wherein a ratio of lercanidipine to adsorbing material is in the range from 1:0.1 to 1:20, more preferably in the range from 1:1 to 1: An immediate release stable solid oral dosage form of lercanidipine as substantially described and exemplified herein.

20

21

22