Abstract
The main objective of this project is to design a new extended release gastroretentive mutiparticulate delivery system for verapamil (VP) by incorporation into hydrogel beads made of chitosan. The beads were formed by dropping solutions of VP and chitosan in a solution of tripolyphosphate using a syringe pump with adjustable constant rate. The formed beads were then further crosslinked using glutraldehyde and the excess glutraldehyde were then washed. The physical properties of the prepared beads such as beads sizes, shapes, friabilities and loading efficiencies were determined. The floating characteristics and the release profiles were also studied. The produced beads from all batches showed a very good spherical geometry with mean diameter in the range of 1.3 – 2.0 mm. The drug loading efficiency was around 42% for all batches. The % friabilities were less than 1% indicating that the beads surfaces are highly resistant to attrition. Batches B3 and B4 (prepared using medium molecular weight chitosan) showed both the slowest release rate among all the prepared batches and showed good floating characteristics comprising short onset (around 5 minutes) and the long duration of buoyancy (more than 6 hours). All the batches exhibited a kinetic model of combined mechanism of diffusion partially through a swollen matrix and partially through water-filled pores. The preparation of chitosan beads using this technique would provide a simple and commercially viable method of preparation of chitosan beads for controlling the release of some drugs.
Highlights
IntroductionThe first calcium channel blocker to be approved by the FDA in 1981, is currently the major Ca-antagonist in the market
Verapamil hydrochloride, the first calcium channel blocker to be approved by the FDA in 1981, is currently the major Ca-antagonist in the market
The DSC-thermogram of pure chitosan shows sharp exothermic peak at zero °C which is corresponding to the melting of the adsorbed ice and is present in other three thermograms, in addition to an endothermic peak corresponding to melting of chitosan at 56.6 °C
Summary
The first calcium channel blocker to be approved by the FDA in 1981, is currently the major Ca-antagonist in the market. It is effective in managing and treating supraventricular tachycardias including paroximal supraventricular tachycardia, atrial fibrillation and/or flutter, and re-entrant tachycardias involving the AV node [1,2]. It is effective in the treatment of hypertension and chronic stable, variant, and unstable angina. Some reports showed that side effects and therapeutic responses were beneficially modified when sustained release forms were used [6,7]
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