TAILOR-MADE POLYVINYL ALCOHOL CRYOGELS FOR PHARMACEUTICAL APPLICATIONS

Objective. The main objective of this study was to characterize adhesive, swelling and viscoelastic properties of Polyvinyl alcohol (PVOH) cryogels Background. PVOH is a hydrophilic linear polymer commonly used as filmformer, emulsifier, and binder in variety of pharmaceutical dosage forms including tablets, transdermal patches, ophthalmic gels, and implants. PVOH can also undergo chemical or physical gelation, which can be utilized for specialized applications such as in controlled drug delivery. Aqueous solutions of PVOH undergoes cryogelation when exposed to repeated freeze-thaw cycles. The cryogels prepared as such possess unique mechanical, elastic, adhesive, and swelling properties, which can be utilized in developing platforms for controlled and novel drug delivery applications. Methods. PVOH aqueous solutions were prepared by dissolving the polymer (PVOH, 99% hydrolyzed, MW 124K-188K, Sigma Aldrich) in deionized water at 90oC under mechanical mixing. The corresponding cryogels were prepared using three different PVOH concentrations (5, 8, 10 wt%) and subjected to two freeze-thaw cycles consisting of freezing at -10oC for 4 hr and thawing at 25oC for 2 h. Adhesive properties were measured using a CT3 Texture analyzer, swelling properties by gravimetry, gumminess by running a texture profile analysis, whereas hardness was measured by compression test using Volodkevich bite jaws (Brookfield Engineering). Results. Cryogels prepared at different concentrations displayed adhesive forces ranging 83-430mN, adhesiveness ranging 0.07-0.36mJ, gumminess ranging 5-22N, hardness ranging 1114mJ, and swelling ranging 10- 50%. Conclusion. Adhesive properties and gumminess decreased with increase in polymer concentration whereas hardness and swelling increased with increase in concentration. Grants. NSU grants# 335867 and 33548