Radiotelemetric method for evaluating enteric coatings in vivo

Area of Science:

• Pharmacology
• Gastroenterology
• Drug Delivery Systems

Background:

• Evaluating enteric coating performance is crucial for effective oral drug delivery.
• Existing methods for assessing enteric coatings have limitations.
• Radiotelemetry offers a potential non-invasive approach for in vivo analysis.

Purpose of the Study:

• To describe and evaluate a novel radiotelemetric method for in vivo assessment of enteric coating performance.
• To compare the advantages and disadvantages of this method with existing techniques.
• To determine the optimal formulation for studying enteric coating efficacy using this method.

Main Methods:

• Developed a radiotelemetric technique to monitor pH changes in the canine gastrointestinal tract.
• Used enteric-coated tablets with buffer cores and hydroxypropyl methylcellulose phthalate as the coating material.
• Monitored gastric and upper intestinal pH to detect tablet disintegration and gastric emptying.

Main Results:

• The radiotelemetric method successfully detected enteric coating disintegration in the upper intestine and premature gastric rupture.
• Average gastric emptying time was 80 ± 18 min, and upper intestinal disintegration time was 14.2 ± 2 min.
• The method demonstrated high reproducibility, with no significant effect of tablet batch or dog variability on disintegration times.

Conclusions:

• Radiotelemetry provides a reproducible and effective in vivo method for evaluating enteric coating performance.
• Buffering the tablet core to pH 4 was found to be most suitable for studying enteric coating performance.
• While in vitro correlation was low, in vivo results aligned with previous human studies.