Flow, compressive, and bioadhesive properties of various blends of poly(ethylene oxide)

Poly (ethylene oxide) (PEO) is nonionic, water soluble, and highly hydrophilic polymer with well-established applications in mucoadhesives, water-soluble films, rheology control agents and thickeners, and additives in pharmaceutical products.

Different powder blends containing PEO in varying proportions were evaluated for their flow, compressive, and bioadhesive properties and subsequently compressed into gastroretentive tablets. Two optimized formulations, on the basis of above-mentioned examinations, were subjected to gamma scintigraphy studies on human volunteers.

The values of bulk and tapped densities, Hausner ratio and Carr index, angle of repose, loss on drying, total moisture content, and particle size distribution provided a fine estimation of flowability and compressibility of the powder blends. Further, apart from the routine pharmacopoeial assessments, the evaluation of compressed tablets for their surface pH in both acidic and basic environments nullified the possibility of any irritation to the membrane where it is intended to adhere. The measurement of swelling index and bioadhesive strength of tablets revealed that both the parameters were a direct function of the concentration of PEO in the tablet. The results of gamma scintigraphy indicated a fourfold increase in the gastric retention time of the optimized formulation vis-à-vis control formulation.

The results indicate that PEO, in a concentration of 10-50% (w/w), can be successfully employed in manufacturing gastroretentive tablets.