Study of the Release Mechanism of Terminalia chebula Extract from Nanoporous Silica Gel

• Published in: Applied biochemistry and biotechnology 2012-12, Vol.168 (7), p.2043-2056
• Main Authors: Chakraborty, Suparna, Mitra, Manoj Kumar, Chaudhuri, Mahua Ghosh, Sa, Biswanath, Das, Satadal, Dey, Rajib
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Biochemistry; Biological and medical sciences; Biotechnology; Chemistry; Chemistry and Materials Science; Chloroform - chemistry; Drug Carriers - chemistry; Fourier transforms; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Kinetics; Methanol - chemistry; Microbial Sensitivity Tests; Nanomaterials; Nanopores; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Porosity; Silica; Silica Gel - chemistry; Terminalia - chemistry; Terminalia chebula; Ultraviolet spectroscopy; Water - chemistry
• ISSN: 0273-2289; 1559-0291
• DOI: 10.1007/s12010-012-9916-0

Sol/gel-derived silica gel was prepared at room temperature from tetraethyl orthosilicate precursor. The extracts of Terminalia chebula (Haritoki) were entrapped into the porous silica gel. Fourier transform infrared analysis revealed the proper adsorption of herbal values in the nanopores of the silica gel. Porosity was estimated by transmission electron microscope studies. The release kinetics of the extract in both 0.1 N HCl, pH 1.2, and Phosphate-buffer saline (PBS), pH 7.2, were determined using UV–Vis spectroscopy. Different dissolution models were applied to release data in order to evaluate the release mechanisms and kinetics. Biphasic release patterns were found in every formulation for both the buffer systems. The kinetics followed a zero-order equation for first 4 h and a Higuchi expression in a subsequent timeline in the case of 0.1 N HCl. In the case of PBS, the formulations showed best linearity with a first-order equation followed by Higuchi’s model. The sustained release of the extract predominantly followed diffusion and super case II transport mechanism. The release value was always above the minimum inhibitory concentration.