Related Experiment Video
Updated: Aug 19, 2026

Slow-release Drug Delivery through Elvax 40W to the Rat Retina: Implications for the Treatment of Chronic Conditions
Published on: September 17, 2014
In vitro evaluation of a sustained-release veterinary peroral pellet preparation
W A Ritschel1, P Agrawala, M Kraeling
1University of Cincinnati Medical Center, Division of Pharmaceutics and Drug Delivery Systems, OH 45267.
Abstract:
In a preceding in vivo study in horses, wide interindividual variation was found in the extent of bioavailability and time to reach peak concentration after peroral administration of one specific theophylline sustained-release dosage form. The purpose of the present study was to investigate the factors of potency, the pH of dissolution medium, the enzymes in the dissolution medium, and the crushing of the pellets on in vitro performance. The results show a wide variation in potency for the individual units, an increase in release rate with increasing pH, and an increase in release rate if the pellets are crushed. The wide variation in potency explains the variation found in absolute bioavailability, and the increase in release rate when the pellets are crushed explains the differences seen in peak plasma times, since the pellets will be chewed to varying degrees by the horse.
More Related Videos
Related Concept Videos
In Vitro Drug Release Testing: Overview, Development and Validation
In Vitro Drug Dissolution: Compendial Testing Models I
In Vitro Drug Dissolution: Compendial Testing Models II
In Vitro Drug Dissolution: Alternative Methods

