Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Effect of Solvent Type and Drying Method on Protein Retention in Chitosan-Alginate Microcapsules

Edith I Ahonkhai, Ikhuoria M Arhewoh, Augustine O Okhamafe

Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, University of Benin, Benin City 300001, Nigeria.;

For correspondence:- Augustine Okhamafe Email: okhamafe@uniben.edu Tel:+234-(0)8037269910

Published: 12 December 2006

Citation: Ahonkhai EI, Arhewoh IM, Okhamafe AO. Effect of Solvent Type and Drying Method on Protein Retention in Chitosan-Alginate Microcapsules. Trop J Pharm Res 2006; 5(2):583-588 doi: 10.4314/tjpr.v5i2.2

© 2006 The authors.
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Abstract

Purpose: The effect of solvent used in dissolving chitosan (membrane material) and the microcapsule drying method used, on protein retention in chitosan-alginate microcapsules were studied since these factors affect the physicochemical characteristics of the coating membrane.
Method: The microcapsules were prepared by extruding a solution containing alginate and BSA into chitosan/calcium chloride solution prepared with different acid solvents – acetic acid, formic acid, tartaric acid and hydrochloric acid. A portion of the microcapsules was air-dried at ambient temperature while the remaining portion was freeze-dried. The elution of protein from the microcapsules in simulated gastric fluid was monitored spectrophotometrically at λmax 280 nm.
Results: Tartaric acid effected the highest mean protein retention (54%) after 9 h followed by acetic acid (35%), hydrochloric acid (31%) and formic acid, (30%). There appears to be a link between the pKa of the acids and the degree of chitosan–solvent interaction on the one hand, and protein retention on the other hand. Increase in elution pH from 1.2 t o 5.0 did not significantly (P>0.05) affect protein retention. Furthermore, there was no significant difference (p>0.05) between the protein retention capacities of air-dried and freeze-dried microcapsules as both types showed protein retention of 50% after 5 h. Conclusion: Tartaric acid was the most suitable solvent for enhancing protein retention in chitosan-alginate microcapsules in simulated gastric fluid.

Keywords: Tartaric acid, chitosan, solvent type, microcapsules, air-drying, freeze-drying.