Enteric coating derived from marine sponge collagen

Enteric coating prevents oral dose forms from being digested in the stomach, which is required for drugs that are acid unstable, have an irritant effect on the stomach, or are designed to act in the small intestine.

The objective of this study was to develop a novel gastroresistant delayed-release tablet coating based on the marine sponge Chondrosia reniformis Nardo and to investigate the technical feasibility of the coating process.

An aqueous gastroresistant coating dispersion on the base of freeze-dried sponge collagen 15% (w/w) as the film-forming agent was developed. The disintegration test for gastroresistant tablets (Ph. Eur.) was carried out at increasing coating levels to reveal the required collagen layer thickness. Reproducibility of the method, physical properties, and stability of the coated tablets were investigated.

Tablets coated with 13 mg/cm(2) of sponge collagen resisted more than 2 hours to 0.1 M hydrochloric acid, and disintegration of all tablets occurred within 10 minutes in phosphate buffer solution (pH 6.8). The method was reproducible, the mechanical properties of the coated tablets were satisfactory, and the obtained tablets could be stored for at least 6 months without loosing enteric properties.

The novel coating based on the marine sponge collagen (using 12.9 mg/cm(2) coating material) complied with the requirements of Ph. Eur. for gastroresistant tablets. This coating material also meets the regulatory requirements for dietary supplements.