The Pharma Innovation Journal 2018; 7(10): 447-455 ISSN (E): 2277- 7695 ISSN (P): 2349-8242 NAAS Rating: 5.03 Comparitive in-vitro drug release study of enteric TPI 2018; 7(10): 447-455 © 2018 TPI coated rabeprazole tablets using synthetic and www.thepharmajournal.com Received: 21-08-2018 natural polymers Accepted: 24-09-2018 Sofia Konain Sofia Konain and Sirisha Mittapally Deccan School of Pharmacy, Dar-us-salam, Aghapura, Nampally, Hyderabad, Abstract Telangana, India Enteric coated tablets are tablets which are coated with polymers to prevent the release of drug in the stomach and allow the drug release in the small intestine. Enteric Coating is used to protect the active Sirisha Mittapally Pharmaceutical Ingredient from the acidic environment and to prevent gastric distress caused from a drug Deccan School of Pharmacy, due to irritation. The purpose of this research work is formulation of enteric coated tablets using Dar-us-salam, Aghapura, Synthetic and Natural polymers and comparing their release studies. Nine formulations of Rabeprazole Nampally, Hyderabad, core tablets were formulated from which F9 was found to be the optimized one. Then the optimized core Telangana, India tablet was coated with 4 different polymers- Eudragit L100, HPMC, Sodium Alginate and Shellac with different concentrations F1 to F16. Compatibility studies were performed which showed no interaction. The dissolution study shows that Eudragit L100 has 100% drug release and the natural polymers Sodium Alginate and Shellac were also equally effective. Therefore, it can be concluded based on the experimental studies that the natural polymers can also be a good alternative to synthetic polymers. Out of the two Natural Polymers, Shellac exhibited good performance compared to Sodium Alginate. Keywords: enteric coating, rabeprazole, synthetic polymers, natural polymers, eudragit l100, sodium alginate, shellac, HPMC, anti-ulcer drug Introduction Solid dosage form A solid dosage form is drug delivery system that includes tablets, capsules, sachets and pills as well as a bulk or unit-dose powders and granules. Oral route of drug administration is widely acceptable, and drugs administered orally as solid dosage form represents the preferred class of products. Over 90% of drugs formulated to produce systemic effects are produced as solid dosage forms Coatings Coating is a process by which an essentially dry, outer layer of coating material is applied to the surface of a dosage form to confer specific benefits that broadly ranges from facilitating [4] product identification to modifying drug release from the dosage form . Reasons for tablet coating The core contains a material which has a bitter taste in the mouth or has an unpleasant odour. Coating will protect the drug from the surroundings with a view to improve its stability. Coating can modify the drug release profile, e.g., enteric coating, osmotic pump, pulsatile delivery [6]. Enteric coating An enteric coating is a barrier that controls the location of oral medication in the digestive system where it is absorbed. The word “enteric” indicates small intestine; therefore enteric coatings prevent release of medication before it reaches the small intestine. The enteric coated polymers remain unionize at low pH, and therefore remain insoluble. But as the pH increases Correspondence Sofia Konain in the GIT, the acidic functional groups are capable of ionization, and the polymer swells or Deccan School of Pharmacy, becomes soluble in the intestinal fluid. Materials used for enteric coatings include CAP, CAT, Dar-us-salam, Aghapura, PVAP and HPMCP, fatty acids, waxes, shellac, plastics and plant fibers. Nampally, Hyderabad, Telangana, India ~ 447 ~ The Pharma Innovation Journal Polymers for enteric coating Polyvinyl derivatives polyvinyl acetate phthalate (PVAP) Polymers are substance containing a large number of Polyvinyl Derivatives Polyvinyl acetate phthalate (PVAP) structural units joined by the same type of linkage. Polyvinyl acetate phthalate (PVAP) is manufactured by the These substances often form into a chain-like structure starch, esterification of a partially hydrolyzed polyvinyl acetate with cellulose, and rubber all possess, polymeric properties. pthalic anhydride. This polymer is similar to HP-55 in stability and pH-dependent solubility. It is supply as ready-to- Classification of polymers use or ready-to-disperse enteric systems. Natural polymers Shellac Syntehtic Polymers Shellac is a polymer used in coating applications to provide Polymethacrylates (Methacrylic acid/ethyl acrylate) various functional properties. It can be used in film coatings Two forms of commercially available enteric acrylic resins to achieve enteric applications, aesthetic and immediate- are Eudragit L and Eudragit S both resins produce film that release properties, taste masking, and seal coating. Shellac is a are resistant to gastric fluid. Eudragit L and Eudragit S are natural and versatile polymer used for coating applications. soluble in intestinal fluid at pH 6 to 7 respectively. Eudragit L is available as an organic solution, solid, or aqueous Sodium alginate dispersion. Eudragit S is available as an organic solution and Sodium alginate is the sodium salt form of alginic acid and solid [4]. gum mainly extracted from the cell walls of brown algae, with Rabeprazole is a proton pump inhibitor that suppresses gastric chelating activity. In tablet formulations, sodium alginate may acid production in the stomach. Rabeprazole's mechanism of be used as both a binder and disinter grant. action involves the permanent inhibition of proton pumps in the stomach, which are responsible for gastric acid Cellulose esters production. Rabeprazole belongs to a class of antisecretory Cellulose esters have been widely used in the industry. CAP compounds that do not exhibit anticholinergic or histamine has the disadvantage of dissolving only above the pH 6, and H2-receptor antagonist properties but suppress gastric acid possibly delaying the absorption of drugs. HPMCP-50, secretion by inhibiting the gastric H+/K+ATPase at the 55,55S these are derived from Hydroxy propyl cellulose, secretory surface of the gastric parietal cell. these polymers dissolves at low pH (5 to 5.5) than CAP or acrylic co-polymers. 2. Materials and Methods Materials Table 1: List of Ingredients S. No. Materials Category Suppliers 1 Rabeprazole Proton Pump Inhibitors Reddy Laboratories, Hyderabad 2 Micro Crystalline Cellulose Diluent S.D.Fine Chem.Ltd,Mumbai,India 3 Cross Providone Superdisintegrant S.D.Fine Chem.Ltd,Mumbai,India 4 Crosscarmellose Sodium Superdisintegrant Myl Chem.Ltd,Mumbai,India 5 Sodium Starch Glycolate Superdisintegrant Myl Chem.Ltd,Mumbai,India 6 Magnesium Stearate Lubricant S.D.Fine Chem.Ltd,Mumbai,India 7 Starch Binder Essel Fine Chem. Mumbai 8 Lactose Monohydrate Filler Essel Fine Chem. Mumbai 9 Aerosil Glidant Myl Chem.Ltd,Mumbai,India 10 Eudragit L 100 (%W/W) Film Former S.D.Fine Chem.Ltd,Mumbai,India 11 Hpmc Hydrophilic Polymer S.D.Fine Chem.Ltd,Mumbai,India 12 Sodium Alginate Release-Retarding Agent S.D.Fine Chem.Ltd,Mumbai,India 13 Shellac Polymer Myl Chem.Ltd,Mumbai,India 14 Acetone Solvent Myl Chem.Ltd,Mumbai,India Experimental Methods Preparation of 6.8pH phosphate buffer Determination of λmax of Rabeprazole Dissolve 28.80g of disodium hydrogen phosphate and 11.45g Standard Stock solution: 100 mg of Rabeprazole was of potassium dihydrogen phosphate in sufficient water to dissolved in 100 ml of pH 6.8 phosphate buffer (1000 μg/ml) produce 1000ml. Scanning: From the stock solution 10μg/ml was prepared in methanol and UV scan was taken between 200 to 400 nm. Calibration curve of rabeprazole in 6.8pH phosphate The absorption maximum was found to be 282 nm and was buffer used for the further analytical studies. From the standard stock solution (1000 μg/ml), appropriate aliquot were transferred to series of 10 ml volumetric flasks Calibration curve of rabeprazole in 0.1N HCL and made up to 10 ml with 6.8pH phosphate buffer so as to From the standard stock solution (1000 μg/ml), appropriate get concentration of 4, 8, 12,16 and 20 μg/ml. the absorbance aliquot were transferred to series of 10 ml volumetric flasks of the solution were measured at 282nm. This procedure was and made up to 10 ml with 0.1 N HCL, so as to get performed in triplicate to validate calibration curve. A concentration of 4, 8, 12,16 and 20 μg/ml. the absorbance of calibration graph was plotted. the solution were measured at 282nm. This procedure was performed in triplicate to validate calibration curve. A Formulation development of rabeprazole enteric coated calibration graph was plotted. tablets An ideal mixture of powder is directly punched into tablets ~ 448 ~ The Pharma Innovation Journal weighing about 200 mg containing 20 mg of Rabeprazole, using rotary tablet compression machine. Table 2: Compilation of Rabeprazole core Tablets Formulation(mg) F1 F2 F3 F4 F5 F6 F7 F8 F9 Rabeprazole 20 20 20 20 20 20 20 20 20 Sodium starch glycolate 5% 7.5% 10% Cross povidone 5% 7.5% 10% Cross caramellose sodium 5% 7.5% 10% Starch 4% 4% 4% 4% 4% 4% 4% 4% 4% Lactose monohydrate Qs Qs Qs Qs Qs Qs Qs Qs Qs Aerosil 2.5% 2.5% 2.5% 2.5% 2.5% 2.5% 2.5% 2.5% 2.5% Magnesium stearate 2% 2% 2% 2% 2% 2% 2% 2% 2% Total weight 200 200 200 200 200 200 200 200 200 Table 3(a): Enteric Coating Formulation Ingredients EC1 EC2 EC3 EC4 EC5 EC6 EC7 EC8 Eudragit L 100 (%W/W) 2% 4% 6% 8% - - - - HPMC - - - - 2% 4% 6% 8% Sodium alginate - - - - - - - - Shellac - - - - - - - - Acetone QS QS QS QS QS QS QS QS Table 3(b): Enteric coating formulation Ingredients EC9 EC10 EC11 EC12 EC13 EC14 EC15 EC16 Eudragit L 100 (%W/W) - - - - - - - - HPMC - - - - - - - - Sodium alginate 2% 4% 6% 8% - - - - Shellac - - - - 2% 4% 6% 8% Acetone QS QS QS QS QS QS QS QS Rabeprazole enteric coated tablets funnel that was secured with its tip at a given height above the Rabeprazole enteric coated tablets were prepared by direct graph paper was placed on a flat horizontal surface.