DESC:FIELD OF THE INVENTION
[001] The present disclosure pertains to the field of capsules and method for making the same. More particularly, present invention relates to a composition for pullulan based enteric capsules and method for preparation thereof.

BACKGROUND OF THE INVENTION
[002] Capsules are a unique dosage form with a long history of use in pharmacy. The basic idea of a capsule is to enclose the drug or active pharmaceutical ingredient (API) in an odourless and tasteless shell. Typically, there are two main types of capsules, the hard capsule and the soft capsule. Both are designed as per the requirement and the enclosed drug/API within. Generally, dry fills such as powder, pallets, granules, mini tablets, liquids, and/or semisolids are filled within the hard capsules and liquids and semisolids are exclusively filled in soft capsules.
[003] Many drugs get denatured by the acidic conditions of the stomach and thus are required to be delivered in the intestine. Generally, this is achieved by having a barrier to prevent the gastric acids in the stomach from dissolving or degrading the drugs. Globally, different techniques have been used for providing enteric properties to the capsules. One of the common techniques for imparting acid resistance is coating the surface of the capsules with one or more layers of a substance or composition that is known to impart enteric properties. Although, this technique commonly used and was preferred in its early days, however, the same is a laborious and cumbersome process. For capsules to be coated, they must be initially filled with the drug and then properly sealed prior to the coating. Moreover, the techniques used for coating may not yield the same replicative results, thereby creating difficulties in commercialisation of the same.
[004] GB2057876A discloses use of HPMCP (treated with sodium hydroxide or ammonium hydroxide) as an enteric coating applied from aqueous systems which coating remains intact for at least 1 hour in contact with HCl of pH 1.2 at 36 ? to 38 ? and disintegrates within 60 minutes when the pH is raised to 6.8, for example, in a KH2PO4 buffered solution. Unfortunately, where it has been attempted to coat pellets using a film coating formulation designed for coating tablets, but including a totally neutralized form of HPMCP, as described in the above references, it has been found that unsatisfactory processing results are obtained due to mass differences between tablets and pellets. The tablet film coating formulation causes significant adherence and clumping of the pellets.
[005] Indian patent application 201621030524 discloses an acid resistance HPMC capsules comprises 20 to 49% of acid resistant polymer and is hard shell made by mixer of an acid resistance polymer HPMC-AS, reacted with alkali to make aqueous composition solution and a second a film forming polymer is HPMC dispersed first in hot water to make aqueous solution and thereafter cooled such that ratio of the dry basis HPMC-AS to HPMC will be between 20:80 to 49:51; further processing aids such as colourants, plasticizers, surfactants like added during mixing of the said solutions.
[006] Enteric polymers and enteric coatings are disclosed generally in US4518433 and US5330759. However, these citations do not teach or suggest the invention as set forth herein.
[007] Given the aforementioned drawbacks, the other technique used to impart enteric property to the capsules is by incorporating the use of enteric agents/polymers during the process of preparation of the capsules. However, only using enteric agents/polymers make the capsule water sensitive and/or brittle, thereby resulting in loss of the intended function. Thus, there is a need to develop a reliable, safe, and economic way to manufacture commercially sustainable capsule shells exhibiting enteric properties.
SUMMARY
[008] In accordance with an embodiment of the present invention, disclosed is a composition for preparing enteric capsules. The composition comprises at least one enteric base material in an amount in the range of 0.1 to 50 wt%, at least one capsule film forming agent in an amount in the range of 5 to 90 wt%, at least one gelling agent in an amount in the range of 0.1 to 25 wt%, and at least one excipient in an amount in the range of 0.1 to 20 wt%. In accordance with another embodiment of the present invention, disclosed is a method for preparing enteric capsules. The method comprises initially mixing pre-determined amounts of at least one enteric base material and water to form an aqueous mixture using suitable neutralising agent. Further, at least one capsule forming agent/polymer, at least one gelling agent/gel promoter and at least one excipient are added in pre-determined amounts to the aqueous mixture under stirring conditions to obtain the aqueous homogeneous film-forming composition. This aqueous homogeneous film-forming composition is then poured in a dipping dish and simultaneously suitable metal mold pins are maintained at a pre-determined temperature. These pins are then dipped in the aqueous homogeneous film-forming composition followed by withdrawing the dipped pins from the aqueous homogeneous film-forming composition at a predefined sequence of velocity and time such that a wet film is formed on the pins upon lifting from the composition. Then, the pins are subjected to a stream of air of pre-determined temperature, relative humidity and velocity such that the wet film is gradually dried to obtain a capsule body and cap portions. The capsule body and cap portions are cut at required length and joined to obtain the enteric capsule.

DETAILED DESCRIPTION OF THE INVENTION
[009] The following is a detailed description of embodiments of the present disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0010] Unless the context requires otherwise, throughout the specification which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”
[0011] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0012] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0013] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable.
[0014] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[0015] All methods described herein can be performed in suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0016] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0017] Various terms are used herein. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0018] The present invention discloses enteric capsules and a method for preparation thereof. In one aspect, the present disclosure discloses enteric capsules. More particularly, the enteric capsules have telescopically engaged body and cap portions. As used herein, the term "enteric properties" means the properties of being soluble in or disintegrated by the alkaline intestinal secretions but being substantially insoluble or resistant to solution in the acid secretions of the stomach for at least 120 mins. The guide norms for drug release are as per pharmacopeial standards. The term "capsules" means hard shell capsules (optionally containing medicament) each having telescopically engaged body and cap portions formed by a technique commonly known as the dip-molding technique. The term "enteric capsules" means such capsules having enteric properties.
[0019] The enteric capsules of the present disclosure, have capsule body and cap portions formed by dip-molding using an aqueous homogeneous film-forming composition. The composition comprises at least one enteric base material, at least one capsule forming agent, at least one gelling agent and at least one excipient. The "aqueous composition" used herein indicates a composition in which at least the enteric base material, the capsule forming agent, and the neutralizing agent are dissolved in water.
[0020] The at least one enteric base material is selected from the group consisting of, but not limited to, Hydroxypropyl methylcellulose phthalate (HPMC phthalate), HPMC-Acetate succinate, methacrylate base co-polymers and the like. The enteric base material that is not dissolved in gastric juice having an acidic pH for about 2 hours but rapidly dissolved in small intestinal juice having an alkaline pH as prescribed in various pharmacopoeias.
[0021] HPMC Phthalate (hydroxypropyl methylcellulose phthalate), is an acid resistant cellulose polymer. The chemical structure is a mono-phthalic acid ester of Hypromellose dissolving easily in different organic solvents into a clear solution. It can dissolve at pH 5-5.5 and be controlled by varying the phthaloyl content.
[0022] pH-triggered release mechanisms are extensively used in oral administration to protect acid-labile drugs from the harsh conditions of the stomach, to obtain either a delayed release or to target specific regions of the gastrointestinal tract. Enteric polymers such as hydroxypropyl methylcellulose phthalate (HPMCP) is anionic polymers that exhibit pH-dependent solubility due to deprotonation of acidic functional groups at intestinal pH, where the drug is released.
[0023] HPMCP as enteric coating agent is insoluble in acidic environment like in gastric juice but dissolves immediately after the transfer of enteric polymer to the small intestine, as example. It is prepared from highly purified pulp, a widely distributed natural material. Typically, the at least one capsule film forming agent is selected from the group consisting of, but not limited to, pullulan, gelatin, HPMC, starch and the like. Typically, the capsule film forming agent improves elasticity of the fragile film of the enteric base material to improve capsule formability/ flexibility.
[0024] Pullulan (also known as 4,4,6-trigluco-polysaccharide) is a natural, viscous polysaccharide extracellularly produced by growing certain yeasts (fungus of Aureobasidium) on starch syrups. It has good film forming properties and particularly low oxygen and moisture content at 50% RH of about 12%.
[0025] Chemically pullulans, is an a-glucan consisting mainly of maltotriose as repeating units linearly jointed through a-1,6-glycosidic linkages. The pullulan is usually obtained in the form of an amorphous white powder and is non-toxic, odourless, edible but is non-digestible. Pullulan is a natural product of non-animal origin made without the need for chemical modification. The resulting films formed with pullulan have excellent homogeneity and transparency. In addition, such films have very low oxygen permeability. Such films and resulting capsules made from pullulan also have relatively low water content, and exhibit high stability over storage, such as with respect to mechanical and dissolution properties.

[0026] Starch is the main carbohydrate in foods and is an important food ingredient for many food products. Most of the research have focused on the mainstream starches such as maize, potato, rice, tapioca and wheat starches, which are the major sources used for the commercial extraction of starch globally . Starch as a common polysaccharide is a polymer made of large number of saccharide molecules a. Starch is available in nature from various types of commodities such as corn, tapioca, potato, corn and maize.
[0027] Structure of starch is a semi-crystalline granular shaped molecule composed of two types of polysaccharides namely amylose and amylopectin. Amylose has relatively straight chain structure, whereas amylopectin is a polysaccharide molecule that has a branched chain structure. The size and shape of the starch granules is determined by the branched structure of amylopectin rather than amylose compared with tapioca and corn, the granule size of potato is the biggest and possessed the lowest gelatinization temperature. The granule size appeared to correlate with gelatinization temperature. The smaller the size of starch granule, the higher the gelatinization temperature.

[0028] Table showing characteristics of various starches:
Starch Moisture % Protein % Amylose% Amylopectin% Gelatinization temp Granule size Crystallinity Degree, %
Potato Starch 11.16 0.1 21.36 62.66 61.8 26.9µm 23–25
Tapioca Starch 9.97 <0.10 24.14 64.06 61.4 15.3 µm 35–38
Corn Starch 9.5 0.3 27 75 66 15.9 µm 14–39
Pea Starch 15 0.52-0.72 30-40 60-70 55–61.4 22.9–30.4 µm 25
Maize starch 14 7.5 20-25 75-80 69.26 5-25µm 27

Tapioca starch is preferred because of higher degree of crystallinity which improves the impact resistance of the capsule.
[0029] Typically, the at least one gelling agent is selected from the group consisting of, but not limited to, gellan gum, carrageenan, agar, xanthan gum, curdaline and any other polysaccharide having gelling ability along with its supportive co-gelling agent.
[0030] Typically, the amount of the at least one enteric base material may be in the range of 0.1 to 50% based on the total weight of the dry film composition.
[0031] The amount of the at least one capsule film forming agent may be in the range of 5 to 90 % based on the total weight of the dry film composition.
[0032] The amount of the at least one gelling agent along with co gelling agent may be in the range of 0.1 to 25% based on the total weight of the dry film composition.
[0033] The amount of the at least one excipient may be in the range of 0.1 to 20 % based on the total weight of the dry film composition.
[0034] In an embodiment of the present disclosure, the at least one excipient can be included in the composition as is common in the industry as long as they do not adversely affect the composition. The at least one excipient can be selected from the group of, but not limited to, emulsifier, plasticiser, opacifier, neutraliser, diluent, glidant, disintegrant, colouring agents, flavours, preservatives, opacifying agents, embrittlement inhibiting agents, disintegrants, buffers and the likes.
[0035] In an embodiment of the present disclosure, the colouring agent is selected from the group consisting of annatto, carotene, chlorophyll, cochineal, curcumin, red iron oxide, yellow iron oxide, titanium oxide, black iron oxide, caramel, riboflavin, quinazarine green, alizarin cyanine green, fast green, tartrazine, sunset yellow, quinoline yellow, erythrosine, eosin YS, toney red, ponceau 4R, carmoisine, indigo carmine, brilliant blue, orange G, resorcin brown, naphthol blue black, allura red, lakes salts and the likes.
[0036] In another embodiment of the present disclosure, the plasticizer is selected from the group consisting of glyceryl esters, glycol esters, sorbitan monoesters, sorbitan polyoxyethylene esters, polyoxyethylene ethers, glycerols, polyethylene glycols, polyols, fatty acid esters, glycerol polyethylene, glycol ricinoleate, macrogolglycerides, SLS, Triethyl citrate (TEC), Acetyl Triethyl citrate (ATEC) and triacetine and the likes.
[0037] In still another embodiment of the present disclosure, the neutraliser is selected from the group consisting of sodium hydroxide, potassium hydroxide and ammonia and the likes.
[0038] In an exemplary embodiment of the present disclosure, the composition comprises:
- Pullulan and/or starch;
- Hydroxypropyl methylcellulose phthalate (HPMC phthalate)
- Gellan Gum and/ or agar; and
- at least one or more excipient.
[0039] In an exemplary embodiment of the present invention, the composition is prepared in the dosage form of a capsule. Depending upon the dosage the composition may comprise further excipients necessary for the manufacture of the preferred dosage form and its breakdown following ingestion and may be chosen by those skilled in the art.
[0040] In another aspect of the present invention, disclosed is a method for preparing the enteric capsules. The method comprises initially the following steps:
(i) mixing pre-determined amounts of at least one enteric base material and water to form an aqueous mixture using suitable neutralising agent;
(ii) adding at least one capsule film forming agent, at least one gelling agent and at least one excipient in pre-determined amounts to the aqueous mixture under stirring conditions to obtain the aqueous homogeneous film-forming composition;
(iii) mixing the solution made in steps (i) and (ii) under pre-defined stirring and pre-determined temperature to make homogeneous film forming composition;
(iv) pouring the aqueous homogeneous film-forming composition in a dipping dish and simultaneously maintaining the suitable metal mold pins at a pre-determined temperature;
(v) dipping the pins in the aqueous homogeneous film-forming composition;
(vi) withdrawing the dipped pins from the aqueous homogeneous film-forming composition at a predefined sequence of velocity and time such that a wet film has formed on the pins upon lifting from the composition.
(vii) subjecting the pins with wet film under stream of air of pre-defined temperature, relative humidity and velocity such that the wet film is gradually dried to obtain a capsule body and cap portions; and
(viii) cutting the capsule body and cap portions to required length and joining to obtain the enteric capsule.
[0041] Typically, the wall thickness, top wall thickness of capsules produced by the dip-molding depends on the viscosity and temperature of the dipping solution. If a thin-walled capsule is desired more water is used, whereas if a thick-walled capsule is desired a more concentrated or viscous solution is used.
[0042] Typically, the composition ranges are on dry basis and excluding moisture of the capsule.
[0043] EXAMPLES:
A. Selection of Process to prepare aqueous enteric base material
a. 200 gms of HPMC-P powder was added to 800 gms of distilled water at 10 ?. Then the below mentioned alkali was added under stirring and observed for solution clarity. Further, a 100-micron film of the material was made and allowed to dry at room temperature (25 to 30 ?). This dry film was removed and evaluated for taste and film flexibility and stability.
Trial no HPMC-P in gm Water in gm NaOH in gm Ammonia in ml KOH in gm Solution clarity Film taste Film flexibility
1-1 200 800 12 - - Clear and white Neutral Flexible and stable
1-2 200 800 14 - - Clear and white Neutral Flexible and stable
1-3 200 800 20 - - Clear and white Neutral Brittle and becomes white
1-4 200 800 - 6 - Clear and brown Bitter Brittle and become white
1-5 200 800 - 7 - Clear and brown Bitter Brittle and become white
1-6 200 800 - 9 - Clear and brown Bitter Brittle and become white
1-7 200 800 - - 17 Turbid and white Neutral Flexible and stable
1-8 200 800 - - 19.5 Turbid and white Neutral Flexible and unstable

Manufacturing of capsules
To manufacture capsules, correct combination of film forming base and enteric polymer along with suitable gelling agent and gel promoter is to be evaluated. Compositions were made with 19 % concentration as per following combinations and capsules were manufactured with hand dipping method. The combinations where good capsule can be formed were then tested for dissolution for 120 mins in 0.1 M HCL by paddle method as described in USP/NF.
All the below figures are in percentage. Figures in Col 2 to 4 are dry powder composition in 19% concentration made in water. 6% NaOH was added on dry basis of required quantity of HPMC-P. Figures in col 5 to 10 are percentage on total of dry powder weight of col 2 to 4. TEC was also added as 0.2 % in all combinations on total dry polymer weight.
Trial no HPMC-P Pullulan Tapioca starch Carriage-enan KCL Gellan gum Na2CO3 EDTA AGAR
2-1 10 90 - - 0.6 2.7 - - -
2-2 10 80 10 - - 2.7 0.5 0.9 -
2-3 20 70 10 - 0.6 3.0 - - -
2-4 20 60 20 - 0.6 3.0 - - -
2-5 10 80 10 - - 3.0 0.5 1.0 -
2-6 20 50 30 1.3 1.0 - - - -
2-7 30 60 10 - - 3.0 0.5 1.1 -
2-8 20 65 15 - - - - - 4.1
2-9 10 70 20 - 0.65 3.0 - - -
2-10 10 60 30 - 0.6 2.5 - - -
2-11 20 55 25 - 0.55 2.7 - - -
2-12 20 80 - 1.2 0.9 - - - -
2-13 10 90 - 1.0 0.8 - - - -
2-14 20 80 - - - - - - 3.8
2-15 10 90 - - - - - - 4.2

The capsules were made with above and evaluated for the following parameters:
• Capsule forming ability
• Top wall thickness
• Flexibility/ brittleness
• Solubility up to 120 mins in 0.1 N HCL solution at 37 ?

Trial no Capsule formability Top wall thickness
(TWT) Brittleness/ flexibility Solubility at 0.1 N HCL
2-1 Good capsule Good TWT Flexible Withstands up to 120 min
2-2 Not good capsule Low TWT Flexible Fails before 120 mins
2-3 Good capsule Good TWT Flexible Withstands up to 120 min
2-4 Good capsule Good TWT Flexible Withstands up to 120 min
2-5 Not good capsule Low TWT Flexible Fails before 120 mins
2-6 Good capsule Good TWT Flexible Fails before 120 mins
2-7 Not good capsule Low TWT Flexible Fails before 120 mins
2-8 Good capsule Good TWT Flexible Withstands up to 120 min
2-9 Good capsule Good TWT Flexible Withstands up to 120 min
2-10 Good capsule Good TWT Flexible Fails before 120 mins
2-11 Good capsule Good TWT Flexible Withstands up to 120 min
2-12 Good capsule Good TWT Flexible Fails before 120 mins
2-13 Good capsule Good TWT Flexible Fails before 120 mins
2-14 Good capsule Good TWT Flexible Withstands up to 120 min
2-15 Good capsule Good TWT Flexible Fails before 120 mins

B. Manufacturing capsules on pilot continuous machine and evaluation for enteric property.
Based on the learnings from A and B above final composition matric was made as follows:
All the below figures are in percentage. Figures in Col 2 to 4 are dry powder composition in 18% concentration made in water. Figures in col 6 to 8 are percentage on total of dry powder weight of col 2 to 4.
Trial no Pullulan Tapioca starch HPMC-P NaOH % on (4) Gellan gum KCL TEC Conc.
(1) (2) (3) (4) (5) (6) (7) (8) (9)
3-1 90 - 10 0.6 2.5 0.6 0.2 18
3-2 90 - 10 0.6 3 0.6 0.2 18
3-3 81 9 10 0.6 2.5 0.6 0.2 18
3-4 72 18 10 0.6 2.5 0.6 0.2 18
3-5 80 - 20 1.2 2 0.6 0.2 18
3-6 80 - 20 1.2 2.5 0.6 0.2 18
3-7 80 - 20 1.2 3 0.6 0.2 18
3-8 72 8 20 1.2 2.5 0.6 0.2 18
3-9 72 8 20 1.2 2.7 0.6 0.2 18
3-10 64 16 20 1.2 2.5 0.6 0.2 18
3-11 64 16 20 1.2 2.7 0.6 0.2 18

The dipping compositions were made as per above combinations and capsules were manufactured on continuous dipping pilot machine. The dipping compositions were checked for viscosity at 65 ?, concentration. The good capsules so manufactured were filled with Acetaminophen formulation and evaluated for dissolution test method in acidic medium (0.1N HCL) as guided in USP for 120 mins and then subjected to 6.8 pH buffer as suggested in JP-2nd. The results are as tabulated below
Trial no Conc. Viscosity Drug release % in
0.1 N HCL (1.2 pH) 6.8 pH
30 min 60 min 90 min 120 min 60 min
3-1 18.3 550 1.92 5.89 8.81 11.9 81.5
3-2 17.8 540 4.3 7.5 9.3 10.0 82.5
3-3 18.1 795 0.65 3.45 5.88 9.23 85.8
3-4 18.1 863 2.11 5.30 11.9 25.5 82.7
3-5 17.6 455 0.86 2.30 3.8 18.1 85.14
3-6 17.5 610 1.36 5.05 9.21 10.0 84.4
3-7 17.6 940 3.1 5.1 8.2 9.5 100
3-8 18.1 794 1.34 4.33 8.75 10.0 86.7
3-9 18.0 1296 1.67 4.52 7.20 10.0 34.8
3-10 18.2 746 0.33 3.16 6.07 8.95 82.5
3-11 18.0 1420 2.02 6.07 9.33 13.08 84.3

As can be seen that there are several combinations where the drug release is below 10 % as required in USP also drug release above 80 % within 60 mins at 6.8 pH confirming the enteric status of capsules.
[0044] While the foregoing description discloses various embodiments of the disclosure, other and further embodiments of the invention may be devised without departing from the basic scope of the disclosure.

,CLAIMS:1.) A composition for preparing enteric capsules, comprising:
- at least one enteric base material in an amount in the range of 0.1 to 50 wt% based on the total weight of the dry film composition;
- at least one capsule film forming agent/polymer in an amount in the range of 5 to 90 wt% based on the total weight of the dry film composition;
- at least one gelling agent/gel promoter in an amount in the range of 0.1 to 25 wt% based on the total weight of the dry film composition; and
- at least one excipient in an amount in the range of 0.1 to 20 wt% based on the total weight of the dry film composition.
2.) The composition as claimed in claim 1, wherein said at least one enteric base material is selected from the group consisting of Hydroxypropyl methylcellulose phthalate (HPMC phthalate), HPMC-Acetate succinate and methacrylate base co polymers.
3.) The composition as claimed in claim 1, wherein said at least one capsule film forming agent is selected from the group consisting of pullulan, gelatin, HPMC, starch alone or in combination.
4.) The composition as claimed in claim 1, wherein said at least one gelling agent is selected from the group consisting of gellan gum, carrageenan, agar, xanthan gum and curdaline.
5.) The composition as claimed in claim 4, said co-gelling agent is potassium chloride.
6.) The composition as claimed in claim 1, wherein said at least one excipient is selected from the group consisting of emulsifier, plasticiser, opacifier, neutraliser, diluent, glidant, disintegrant, colouring agents, flavours, preservatives, opacifying agents, embrittlement inhibiting agents, disintegrants and buffers.
7.) The composition as claimed in claim 6, wherein said colouring agent is selected from the group consisting of annatto, carotene, chlorophyll, cochineal, curcumin, red iron oxide, yellow iron oxide, titanium oxide, black iron oxide, caramel, riboflavin, quinazarine green, alizarin cyanine green, fast green, tartrazine, sunset yellow, quinoline yellow, erythrosine, eosin YS, toney red, ponceau 4R, carmoisine, indigo carmine, brilliant blue, orange G, resorcin brown, naphthol blue black, allura red and lakes salts.
8.) The composition as claimed in claim 6, wherein said plasticizer is selected from the group consisting of glyceryl esters, glycol esters, sorbitan monoesters, sorbitan polyoxyethylene esters, polyoxyethylene ethers, glycerols, polyethylene glycols, polyols, fatty acid esters, glycerol polyethylene, glycol ricinoleate, macrogolglycerides, SLS, Tryethyl citrate (TEC), Actyl Tryethyl citrate (ATEC) and triacetine.
9.) The composition as claimed in claim 6, wherein said neutraliser is selected from the group consisting of sodium hydroxide, potassium hydroxide and ammonia.
10.) A composition for preparing enteric capsules, comprising HPMC phthalate, pullan, starch, gellan gum, potassium chloride and at least one excipient.
11.) A method for preparing the enteric capsules, said method comprises:
- mixing pre-determined amounts of at least one enteric base material and water to form an aqueous mixture using a pre-determined neutraliser;
- adding at least one capsule forming agent, at least one gelling agent and at least one excipient in pre-determined amounts to the aqueous mixture under stirring conditions to obtain the aqueous homogeneous film-forming composition;
- pouring the aqueous homogeneous film-forming composition in a dipping dish and simultaneously heating the suitable metal mold pins to attain a pre-determined temperature;
- dipping the pre-heated pins in the aqueous homogeneous film-forming composition;
- withdrawing the dipped pins from the aqueous homogeneous film-forming composition at a predefined sequence of velocity and time such that a wet film has formed on the pins upon lifting from the composition;
- subjecting the pins to a stream of air of pre-determined temperature, relative humidity and velocity such that the wet film is gradually dried to obtain a capsule body and cap portions; and
- cutting the capsule body and cap portions to required length and joined to obtain the enteric capsule.
12.) A method for preparing the enteric capsules as claimed in claim 10, wherein said suitable mold pins can be of any size typically used in capsule industry.