Assessment of a dissolution vessel designed for use with floating and erodible dosage forms

Application of a novel symmetrical shape factor to gastroretentive matrices as a measure of swelling synchronization and its impact on drug release kinetics under standard and modified dissolution conditions

Objectives

We have assessed the kinetics of drug release in relation to the full or partial hydration and swelling of matrices under standard and modified United States Pharmacopeia (USP) apparatus II using a novel index, defined as the symmetrical shape factor. The symmetrical shape factor describes the regularity of the hydration rate of the matrix perimeter relative to its central regions.

Methods

Monolithic and three-layer matrices based on hypromellose, polyethylene oxide, Kollidon SR, theophylline, diltiazem hydrochloride and alfuzosin hydrochloride were subjected to dissolution testing.

Key findings

Our results indicated that Kollidon SR matrices and the three-layer composite systems with and without effervescing components were not significantly affected by the dissolution conditions. However, in the case of the floating monolithic systems based on hypromellose and polyethylene oxide, both release profiles and swelling dynamics in accordance with the similarity factor (f2) and symmetrical shape factor values were significantly influenced.

Conclusions

The symmetrical shape factor values were positively impacted. Consequently the drug release kinetics were more predictable and reproducible. The modified USP method resulted in a more synchronized axial and radial swelling with symmetrical shape factor values approaching unity. Data further indicated that the modified USP method provided for complete matrix hydration and swelling as the dosage form remained fully submerged, allowing for more reliable release mimicking the in-vivo conditions.

Floating drug delivery systems: a review

The purpose of writing this review on floating drug delivery systems (FDDS) was to compile the recent literature with special focus on the principal mechanism of floatation to achieve gastric retention. The recent developments of FDDS including the physiological and formulation variables affecting gastric retention, approaches to design single-unit and multiple-unit floating systems, and their classification and formulation aspects are covered in detail. This review also summarizes the in vitro techniques, in vivo studies to evaluate the performance and application of floating systems, and applications of these systems. These systems are useful to several problems encountered during the development of a pharmaceutical dosage form.

Recent developments in oral multiphase and targeted release products

This review examines recent approaches to formulation that are aimed at oral multiphase and targeted release products, and comments on their potential for commercial manufacture. In addition, it identifies a trend within current development in the formation of systems that are designed to alter specific absorption processes. This is in contrast to classical routes, which effectively adapt to normal physiological functions. These new approaches may have two major benefits in both facilitating consistent, reliable oral dosing of new complex molecules, such as those discovered within the biotechnology industry, and permitting dosage reduction of current common molecules.