Evaluation of Release Retarding Efficiency of Calcium Starch – A New Modified Starch in Comparison to Known PolymersAuthor(s): G. Sailaja and K. P. R. Chowdary
The objective of the present study is to make a comparative evaluation of the drug release retarding efficiency of calcium starch, a new modified starch in comparison to known polymers namely hydroxyl propyl methyl cellulose (HPMC), sodium carboxy methyl cellulose (sodium CMC), ethyl cellulose and olibanum gum. Matrix tablets of gliclazide (30 mg) were prepared employing calcium starch and the other polymers at a polymer concentration of 5% and the tablets were evaluated. Gliclazide release from all the matrix tablets formulated with calcium starch and various other polymers was slow and spread over 12-24 hrs. Non-fickian diffusion was the release mechanism from all the matrix tablets prepared. Gliclazide release from the matrix tablets prepared employing sodium CMC, olibanum gum, ethyl cellulose and HPMC was relatively rapid and the release was complete in 12 hrs. Whereas gliclazide release was slow and spread over 24 hrs with calcium starch. The order of increasing release retarding effect with various polymers was sodium CMC < olibanum gum < Ethyl cellulose < HPMC < Calcium starch. Calcium starch is a better release retarding polymer than sodium CMC, olibanum gum, ethyl cellulose and HPMC for obtaining controlled release over 24 hrs.