In vivo predictive release methods for medicated chewing gums

Understanding the performance of a drug product in vivo plays a key role in the development of meaningful in vitro drug release methodology. In case of functional chewing gums, the mode and the mechanism of release and the site of application differ significantly from other conventional solid oral dosage forms and require a special consideration to extract meaningful information from clinical studies. In the current study, suitable drug release methodology was developed to predict the in vivo performance of an investigated chewing gum product. Different parameters of the drug release testing apparatus described in the Ph. Eur. and Pharmeuropa were evaluated. Drug release data indicate that the parameters, chewing distance, chewing frequency and twisting motion, affect the drug release. Higher drug release was observed when the frequency was changed from 40 chews/min to 60 chews/min for apparatus A and B, as was the case for the twisting motion when changed from 20º to 40º for apparatus B. As far as the chewing distance is concerned, the release rate was in the following order; apparatus A: 0.3 mm > 0.5 mm > 0.7 mm; apparatus B: 1.4 mm > 1.6 mm > 1.8 mm. A suitable apparatus set-up for in vitro release testing was identified. The method will be useful for the establishment of in vitro in vivo correlations (IVIVC) for medicated chewing gums. Interchangeability of the apparatus for a product is not generally recommended without prior knowledge of the performance of the product, as the construction and principle of operation for the apparatus differ considerably.