EFFECT OF POLYMERS AND GAS FORMING AGENTS ON GASTRO-RETENTIVE FLOATING TABLETS OF ACYCLOVIR

Abstract

Acyclovir is a potent antiviral drug with low toxicity used in treatment of herpes simplex infection & varicella zoster infection. It has maximum absorption in the stomach, and half life is 3 hrs. Due to low gastric retention time, the bioavailability of drug is low as the large portion of drug misses the absorption window. Floating matrix tablets are designed to prolong the gastric residence time after oral administration, at a particular site and controlling the release of drug, especially useful for achieving controlled plasma level as well as improving bioavailability. With this objective, floating dosage form containing Acyclovir as drug was designed. Tablets containing hydroxypropylmethylcellulose (HPMC), drug and different additives were compressed using wet granulation. The study shows that tablet composition has great influence on the floating properties and drug release. Incorporation of gas-generating agent together with polymer improved drug release, besides optimal floating (floating lag time ~30 s; total floating time >12 h). The drug release was sufficiently sustained (more than 11h) and non-Fickian as well as zero-order was confirmed.