Studies On Extended-Release Tablets Of Niacin And Lovastatin Compound

Niacin, one of the blood lipid-regulating drugs earliest used to reduce the case fatality rate, has been holding important position in the therapy of high blood-lipid. Nicotinic acid has exact curative effect but show great adverse effects, so it should be made into sustained-release dosage form and co-administered with other drugs such as lovastatin, an eminent drug used for hyperlipidemia to enhance the effects. In this study, niacin and lovastatin were made into compound preparation which can be administered once daily, with nicotinic acid as the part of sustained-release layer and lovastatin as the part of immediate-release layer.In the study, physical and chemical properties of niacin such as equilibrium solubility, stability of aqueous solution in different release media and stability of lovastatin aqueous solution in dissolution medium were tested, results showed that niacin and lovastatin aqueous solution were stable in the different media.Based on the new sustained release material-HPMC, niacin sustained release tablets were manufactured by different technique containing different content of HPMC. Lovastatin was suspended in the coating solution. The niacin extended release and lovastatin tablets were prepared by coating. Tween 80 and PEG400 were introduced into the coating solution as plasticizer to improve the membrane flexibility. The formulation and technology were optimized. Dissolution and content uniformity of lovastatin were also investigated. Results show that lovastatin could dissolute completely within 45 min in vitro and content uniformity of it was ideal. Further test indicated that outer coating had no influence on the release behavior of niacin Results indicated that the formulation and manufacture technique were replicable and suitable for industrial production.The quality standard of extended release tablets of niacin and lovastatin including character, identification, related substance, content, niacin and lovastatin dissolution, lovastatin uniformity was developed. According to the standard, three batch tablets were assayed and all samples complied with the standard.Stress testing, accelerated testing and long-term testing were carried out to investigate the stability of extended-release tablets of niacin and lovastatin. Character, content, related substance, niacin and lovastatin dissolution, lovastatin uniformity were studied. The results showed in relative humidity of 92.5% circumstance for 10 days, the surface of the tablets became rough in 60℃, the related substance of the drug increased...