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The object of the study was to develop a quick and reproducible accelerated in vitro release method to predict and deduce the function of the real time (37 °C) release for long acting PLGA microspheres. The method could be described in several steps. First, the release of the microspheres were studied using the sample and separate method at 37 °C with normal orbital shaking and elevated temperatures with magnetic stirring to further accelerate the release. Second, the most similar profile at elevated temperatures with the real time release was chosen with the help of the n value in the fitted Korsmeyer-Peppas Function. Third, the Weibull function and conversion ratio were used to deduce the function of real time release according to the chosen profile at elevated temperatures. The key point in this study was to provide a quick and precise method to predict the real time release for long acting progesterone PLGA microspheres. So the elevated temperatures coupled with magnetic stirring were used to accelerate the release further, and when there have many similar release profiles with the real time release at elevated temperatures, releasing time at elevated temperatures and the R 2 of the final deduced function will be used to help choosing the most similar release profile with the real time release. Four different types of progesterone PLGA microspheres were used to verify the method, and all the deduced function correlated well with the real time releases, for R² = 0.9912, 0.9781, 0.9918 and 0.9972, respectively. [ABSTRACT FROM AUTHOR]

The aim of the present work was to develop once-daily sustained release microsponges formulations of Nicorandil, a potent potassium channel opener used in cardiovascular diseases and it has low oral bioavailability (70%) and half-life 1 h. So, it is good candidate for sustained release formulations based on microsponge technology. The microsponges were prepared by using quasi-emulsion solvent diffusion method. Scanning Electron Microscopy (SEM) revealed that the microsponges of nicorandil with Eudragit - RSPO and HPMC K100M were smooth, porous, glossy and discrete spherical. The actual drug content and encapsulation efficiency of batch M1 to M9 were obtained in range of 62.05 ± 0.31 to 80.69 ± 0.43 and 64.41 ± 1.71 to 70.58 ± 1.12, respectively. The microsponges formulations were subjected to in-vitro release studies and the results were evaluated kinetically and statically. The best fitted model was found to be Korsmeyer - Peppas model (R² = 0.9992) for M6 batch. The 'n' value for Korsmeyer - Peppas model was between 0.5 and 1.0 which is indicative of non-Fickian diffusion. Statistical analysis using ANOVA yielded a p value of 0.572 for all the formulations, indicating that there was no significant difference among them. [ABSTRACT FROM AUTHOR]

Abstract: The bimodal mesoporous silicas with short random mesoporous channels and MCM-41 with long ordered mesopores were synthesised and modified with 3-(2-aminoethylamino) propyltrimethoxysilane as ibuprofen carriers to study the influence of mesoporous structure on drug delivery property. For further comparing the different mesoporous channels, modified SBA-15 with relative large and long ordered mesopores was also synthesized as drug carriers. The resultant samples were characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, N2 adsorption–desorption isotherms, thermogravimetric analyses, solid-state 29Si NMR spectra, elemental analysis, and UV–vis spectra. Meanwhile, the Korsmeyer–Peppas equation f t = kt n was employed to analyze the drug release profile and three release mediums including simulated fluid solution, distilled water and simulated gastric fluid were used. The results indicated that the modified BMMs with the bimodal mesopores leaded to the most drug loading amount of 25.0 mg/0.1 g, while the MCM-41 with the long and one-dimensional mesopores had the least loading amount around 20.3 mg/0.1 g. Meanwhile, the easier diffusion behavior of drug molecules in the bimodal mesopore channels of BMMs resulted in relatively faster drug release properties in comparison with MCM-41, while the release time maintained in SBF for about 12 h (release percent was about 90 wt%) and corresponding release constant k obtained from Korsmeyer–Peppas equation was around 4.10. [Copyright &y& Elsevier]

Biopolymers have attracted significant attention for the development of drug-carrying systems due to their high degree of biocompatibility, nontoxicity, biodegradability, and renewability. The focus of this work is to examine the optimized conditions for maximum encapsulation and release of anti-cancer drug curcumin using modified biopolymer blend beads of sodium alginate (SA) and carboxymethylcellulose (CMC). Biopolymer blend beads were prepared by mixing equal amounts of SA and CMC using normal syringe method followed by crosslinking with ZnCl2 to improve the stability of the drug carrier. The applicability of the Zn2+ Crosslinked SA/CMC for curcumin was evaluated in terms of entrapment efficiency, swelling, in vitro release and drug release kinetics. Further, pseudo-first order and pseudo-second-order kinetics and isotherm models were applied to the encapsulation data and the results demonstrate that the interaction between curcumin and the biopolymers was physio sorption. The developed biopolymer drug carriers were characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) with and without loading of curcumin to investigate the interactions between the curcumin drug and drug carrier. The obtained results were also analyzed and compared with pristine SA beads. The maximum encapsulation efficiency was found to be 79.75% and 93.07% for SA and SA/CMC blend respectively for the formulations. The in vitro drug release studies were carried out at pH 7.4 in phosphate buffer for 8 h at 37 °C and the results demonstrate the cumulative percentage of curcumin release was increased with increasing carrier concentration. Among several kinetic models of drug release, Korsmeyer-Peppas model exhibited high correlation coefficient (r2) for both the SA and the SA/CMC. [ABSTRACT FROM AUTHOR]