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

Release kinetics of highly porous floating tablets containing cilostazol

This study focuses on developing a highly porous floating tablet containing cilostazol. The underlying release mechanism of cilostazol from porous and floating tablets in dissolution media containing surfactants was investigated. The tablets were prepared by compressing granules and excipients with a sublimating agent, followed by sublimation under vacuum. The volatile material for the sublimating agent was chosen based on its flow properties using conventional methods as well as the twisted blade method. Resultant tablets could float immediately and had significantly higher tensile strengths than conventional tablets of similar porosities, holding a promising potential for increasing gastroretentive properties. Fitting the release profiles to the Korsmeyer-Peppas equation indicated Super Case II, Case II and non-Fickian kinetics, which implied that the release was affected by both floating behavior and matrix erosion. Abrupt changes in release kinetic parameters and erosional behaviors were found between the tablets containing different amounts of HPMC, indicating the existence of an excipient percolation threshold. Neither the surfactant in the media nor the porosity affected the dominant release mechanism, which was matrix erosion. Understanding the dominant release mechanism and percolation threshold allows for tuning the formulation to obtain various release profiles.

Electrostatic Assembly of Poly(ethylene glycol) Nanotubes

Poly(ethylene glycol) (PEG)-based films, nanotubes, and nanotube arrays were successfully made using layer-by-layer (LbL) assembly ion-containing PEO derivatives on porous templates and planar substrates. PEG nanotubes are challenging to produce because PEG dissolves into solutions and solvents used during nanotube processing, but our techniques circumvent the issue. Nanotube dimensions were verified using microscopy and the average observed diameter was 155 nm. The PEG-based structures showed remarkable stability in water, salt water, and sodium hydroxide solution.