Eudragit E100 and Polysaccharide Polymer Blends as Matrices for Modified-Release Drug Delivery II: Swelling and Release Studies

Purpose: To compare the effects of two states of polymer/polymer blending (dry and aqueous/lyophilized) of locust bean gum with Eudragit® E100 and sodium carboxymethylcellulose on swelling and drug (levodopa) release from their tablet matrices.
Methods: Sodium carboxymethylcellulose (SCMC), Eudragit® (E100) and locust bean (LB) were blended in their dry (as purchased) state or modified by aqueous blending and subsequent lyophilization prior to use as tablet matrices. The tablets were evaluated for swelling and in vitro drug release. Furthermore, in vivo absorption was predicted from the in vitro release data by convolution method.
Results: E100 matrices exhibited little or no swelling while the matrices of SCMC and LB and their blends exhibited a degree of swelling > 180 %. Aqueous blending and lyophilization modulated the rate of release from matrices formulated with LB, SCMC and their polymer/polymer blends. Drug release profiles of the lyophilized polymer/polymer blends matrices were dissimilar to those of the dry polymer/polymer blends. Formulations F1aq, F2aq and F3aq exhibited fairly uniform absorption in the first 8 h, indicating the possibility of producing a steady delivery of drug.
Conclusion: Polymer blending of LB, SCMC and E100, achieved by aqueous blending and lyophilization, enhances the performance of the matrices thereby exhibiting controlled levodopa release with no burst effect and the tablets retained their three-dimensional network.

Keywords
Controlled release; Drug delivery; Eudragit; Locust bean; Levodopa; Matrix; Polymer blend; Sodium carboxymethylcellulose