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The objective of this study was to prepare and evaluate some physiochemical and biopharmaceutical properties of bitter taste masking microparticles containing azithromycin loaded in dispersible tablets. In the first stage of the study, the bitter taste masking microparticles were prepared by solvent evaporation and spray drying method. When compared to the bitter threshold (32.43 µg/ml) of azithromycin (AZI), the microparticles using AZI:Eudragit L100 = 1:4 and having a size distribution of 45–212 µm did significantly mask the bitter taste of AZI. Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance spectroscopy ( 1 H NMR) proved that the taste masking of microparticles resulted from the intermolecular interaction of the amine group in AZI and the carbonyl group in Eudragit L100. Differential scanning calorimeter (DSC) analysis was used to display the amorphous state of AZI in microparticles. Images obtaining from optical microscopy and scanning electron microscopy (SEM) indicated the existence of microparticles in regular cube shape with many layers. In the second stage, dispersible tablets containing microparticles (DTs-MP) were prepared by direct compression technique. Stability study was conducted to screen pH modulators for DTs-MP, and a combination of alkali agents (CaCO 3 :NaH 2 PO 4 , 2:1) was added into DTs-MP to create microenvironment pH of 5.0–6.0 for the tablets. The disintegration time of optimum DTs-MP was 53 ± 5.29 s and strongly depended on the kinds of lubricant and diluent. The pharmacokinetic study in the rabbit model using liquid chromatography tandem mass spectrometry showed that the mean relative bioavailability (AUC) and mean maximum concentration (C max ) of DTs-MP were improved by 2.19 and 2.02 times, respectively, compared to the reference product (Zithromax®, Pfizer). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]