Formulation and evaluation of captropril microspheres by ionic gelation technique

The development of oral sustained or controlled release dosage form of captopril has been an interested topic of research for a long period of time. Difficulties encountered on the fact that the drug is freely water soluble. Such drug is difficult to be delivered orally in a sustained or controlled release manner and, Due to its effectiveness and intensive use as a drug of choice in the treatment of hypertension and congestive heart failure, numerous sustained and controlled release formulations of captopril have been made and reported.Captropril microsphere were prepared with a coat consisting of alginate and polymer such as HPMC,Sodium alginate,Sodiun Carboxy methyl cellulose, by Ionic cross linking technic using CaCl2. Key-Words: Captopril, HPMC, Sodium alginate, Sodiun Carboxy methyl cellulose, CaCl2 Introduction Captopril (CAP) is an orally active angiotensen converting enzyme inhibitor. It has proven to have excellent clinical effectiveness in the treatment of essential hypertension and congestive heart failure. However,after single oral dose, the anti-hypertensive action is only effective for 6–8 h. Hence, clinical use requires a daily dose of 37–75mg to be taken three times in divided doses (Nur and Zhang 2000a), development of a controlled delivery system for captopril would be advantageous especially in longterm therapy to maintain relatively constant blood levels for a long period of time. However, the development of oral controlled release formulation for CAP is somewhat difficult (Nur and Zhang 2000a). This could be due to the fact that the drug suffering in vitro and in vivo instability. Besides that the drug is absorbed passively and actively from the GIT. In addition, the drug being water soluble could suffer from dose dumping and burst phenomenon. On the other hand, its bioavailability decreases in the presence of food. * Corresponding Author E-mail: [email protected] Mob.: +91-9752701401 Several attempts have been made to formulate sustained release captopril formulations, for example floating tablets and,bioadhesive systems (Nur and Zhang 2000b), sub-lingual tablets (Chetty et al. 2001), biodegradable(Mandal 1998) and non-biodegradable microcapsules (Singh and Robinson 1988).The objective of this study was to formulate sustained release captopril-alginate microspheres using HPMC and Sodium CMC. The effects of polymer molecular weights and polymer ratios on the particle size, flow properties, morphology, surface properties and the release characteristics of the prepared captopril microsphere were examined. Material and methods Materials Captopril powder (CAP), Sodium alginate, Sodium carboxy methyl cellulose, hydroxy propyl methyl cellulose. Preparation of microsphere The Microspheres were prepared using an ionic crosslinking technique (Das M.K.et al, 2008).The polymeric solution was prepared by dissolving sodium alginate, HPMC, Sodium CMC, in Distilled water. The drug was dissolved in the polymeric solution .The prepared drug-polymer solution was added drop wise by a 20 gauge hypodermic needle in to 50 ml of 5%w/v of crosslinking agents, being stirred at 200rpm for 10 min . Calcium chloride were used as a cross linking agents. The formed captropril microspheres were Research Article [Sahu et al., 3(1): Jan., 2012]