Preparation and Evaluation of Cross Linked Starch Urea - A New Polymer for Controlled Release of DiclofenacAuthor(s): K. P. R. Chowdary and D. Udaya Chandra
In present investigation, cross linked starch – urea, a new starch based polymer has been synthesized and its application in controlled release (CR) and in the design of diclofenac controlled release tablets has been evaluated. Cross-linked starch-urea polymer was synthesized by gelatinization of starch in the presence of urea and crosslinking by treatment with calcium chloride. Matrix tablets each containing 100 mg of diclofenac were formulated employing (i) starch-urea and (ii) cross-linked starchurea in different proportions by wet granulation method and the tablets were evaluated. Cross-linked starch-urea was more suitable than starch-urea for controlled release application. Diclofenac release from the matrix tablets formulated employing cross-linked starch-urea was slow, spread over 24 h and the release was diffusion controlled. Non – Fickian diffusion was the drug release mechanism from these matrix tablets. Diclofenac release from matrix tablets (F4) formulated employing 66 % cross-linked starch–urea was similar to that from Voveran SR tablets, a commercial SR formulation of diclofenac. Diclofenac CR tablets for once-a-day (24 h) administration could be designed employing cross-linked starch-urea.