Evaluation of Sericin as a Binder in Tablet Formulation

Sericin is a protein present in silk cocoons, which envelopes the fibers with sticky layers. Silk proteins ( Sericin and fibroin) are biodegradable and biocompatible. If the sericin is recovered, it can present significant and social benefits, as it is discarded in silk processing industry along with waste water. The influence of sericin, as a binding agent, on bulk, compressional and tabletting characteristics of propranalol Hydrochloride tablet formulation was studied in comparison with the effect of standard binder, starch. Method of sericin extraction was developed and optimized and the yield was 12.75%. Granules, containing Propranalol HCl, were prepared and evaluated for crushing strength, friability and flowability. Granules showed comparable physical characteristics concerning flow properties and crushing strength. Tablets were prepared using sericin and starch as a binder separately and compared for weight variation, hardness, friability, and disintegration and in-vitro dissolution. Sericin yield was 12.75%. Tablets made from sericin had the highest crushing strength and lowest tendency to laminate. All the formulated tablets had friability values less than 1% at the concentration used in the study. Granules exhibited angle of repose in the range of 29(0)-31(0) and crushing strength ranged between 400-600 gms. Sericin did not influence the dissolution of drug by its presence in the dosage form. Two-way ANOVA test showed no significant differences for tablet parameters. Sericin as a binder was comparable to potato starch. The characterization of the formulation suggests that sericin can be developed in to a commercial binding agent for tablets.