Sustained release

ABSTRACTThe aim of the present study is to design and develop sustained release pellets formulations for Amlodipine besylate. Amlodipine is an oral antihypertensive agent, commonly used as calcium channel blocker for treating high blood pressure. It is frequently used to treat heart diseases like angina pectoris. The dose of Amlodipine in case of hypertension or angina initially 5 mg daily later adjusted to 10 mg daily by oral route. Amlodipine has a maximum solubility in acidic pH. Amlodipine has a high bioavailability ranging from 60 to 80 % and slow rate of elimination. Amlodipine besylate at different drug to polymer ratios were prepared by extrusion and spheronization technique. The influence of the proportion of the polymer on the release rate of the drug from the pellets was studied. The in-vitro release studies of pellets were carried out in 0.1N HCl for 12 hours. The studies indicated that the drug release can be modulated by varying the concentration of the polymer. Pellets were prepared and evaluated for loose bulk density, tapped bulk density, compressibility index and angle of repose, shows satisfactory results. Formulation was optimized on the basis of acceptable pellet properties and in-vitro drug release. The resulting formulation produced robust pellets with acceptable drug content and low friability. The release data was fitted to various mathematical models such as, Higuchi, Korsmeyer- Peppas, First-order and Zero-order to evaluate the kinetics and mechanism of the drug release.Keywords: Sustained release, Ethyl cellulose, HPMC, Pellets, Amlodipine besylate  

From the last decade great interest generated on replacing conventional administration of drug by delivery system which would release effective quantities from a protected supply at a controlled rate over a long period of time. An appropriately designated controlled release drug delivery system is the major advance toward solving problems concerning targeting of a drug to a specific organ or a tissue and controlling the rate of a drug delivery to the target site. Matrix system are favoured because of their simplicity, patient compliance etc, than traditional drug delivery(TDS) which have many drawbacks like repeated administration, fluctuation in blood concentration level etc. Developing oral sustained release matrix tablet with constant release rate has always been a challenge to the pharmaceutical technologist. Most of drugs, if not formulated properly, may readily release the drug at a faster rate, and are likely to produce toxic concentration of the drug on oral administration. So that selecting appropriate polymers have become product of choice as an important ingredient for formulating sustained release formulations.