Duodenum-specific drug delivery: in vivo assessment of a pharmaceutically developed enteric-coated capsule for a broad applicability in rat studies.

Targeting new oral drug formulations in the intestine has a broad applicability in animal studies. Enteric-coated capsules are gastroresistant and specific drug delivery systems useful for the evaluation of new pharmaceutical formulations during pre-clinical validations in rats. The purpose of this study was to develop and validate in a large-scale, reliable, reproducible capsules, to offer a safe and standardized duodenum-specific delivery system adapted for studies in rats. The reproducibility of the coating method, the coating layer uniformity and thickness, the external capsules integrity and their enteric properties after in vitro dissolution in simulated gastric and intestinal media were already evaluated and validated. This study presents the in vivo tests of the gastroresistance and of the location of the disintegration. Micro-computerized tomography and a pharmacokinetic study of acetaminophen-filled capsules showed that the enteric-capsules were resistant in the stomach with no apparent leak of the capsules, and were disintegrated in the early duodenum 1-1.5h after oral administration. A positive impact on the bioavailability of acetaminophen in coated capsules was attested. In conclusion, this work, developed with a rigorous pharmaceutical technology, presents a tool adapted for duodenum-specific delivery of new formulations in rats.