Synthesis and characterization of citric acid crosslinked carboxymethyl tamarind gum-polyvinyl alcohol hydrogel films.

The aim of present work was to synthesize and characterize carboxymethyl tamarind gum-polyvinyl alcohol (CMTG-PVA) hydrogel films using citric acid (CA) as a crosslinker. Hydrogel films were prepared by solvent casting technique. The films were evaluated for total carboxyl content (TCC), tensile strength, protein adsorption, permeability properties, hemocompatibility, swellability, moxifloxacin (MFX) loading and release, in-vivo wound healing activity and characterized using instrumental techniques. An optimal increase in amount of PVA and CA increased the TCC and tensile strength of the hydrogel films. Hydrogel films exhibited low protein adsorption and microbial permeation, good permeability to water vapour and oxygen, and sufficient hemocompatibility. The films prepared using high concentration of PVA and low concentration of CA showed good swellability in phosphate buffer and simulated wound fluids. MFX loading in the hydrogel films was found in the range of 384-440 mg/g. The hydrogel films sustained the release of MFX up to 24 h. The release followed Non-Fickian mechanism. ATR-FTIR, solid state 13C NMR and TGA analysis indicated formation of ester crosslinks. In-vivo study revealed good wound healing activity for hydrogel films. From the overall study, it can be concluded that the citric acid crosslinked CMTG-PVA hydrogel films can be effectively used for wound treatment.

Comparison of techniques for the extraction of Camptothecin from Tabernaemontana species.

Extraction methods like maceration, ultrasonication, vortex mixer, soxhlet extraction and microwave assisted extraction (MAE), were evaluated for the extraction of Camptothecin (CPT) from the leaves and stem of Tabernaemontana alternifolia, Tabernaemontana divaricata and Tabernaemontana citrifolia. The extracts were analyzed by high performance thin layer chromatography (HPTLC). The results show that the leaves of Tabernaemontana alternifolia exhibited highest yield of CPT as compared to the other species. MAE was the most efficient extraction method with CPT extraction yield of 0.154 ± 0.004% w/w from Tabernaemontana alternifolia leaves followed by Soxhlet extraction, sonication, maceration, and vortex extraction methods.

Citric acid crosslinked carboxymethylcellulose-poly(ethylene glycol) hydrogel films for delivery of poorly soluble drugs.

In present work, carboxymethylcellulose (CMC) - polyethylene glycol (PEG) hydrogel films were prepared using citric acid as a non-toxic crosslinking agent, for the controlled delivery of model hydrophobic drug (ketoconazole). The carboxyl content of the hydrogel films were determined by acid-base titration. The films were characterized by solid state 13C NMR, ATR-FTIR, TGA and DSC, and evaluated for swelling behavior, drug loading, drug release, hemocompatibility, in vitro cytotoxicity and implantation test. An increase in the amount of PEG caused increase in the carboxyl content and swellability of the hydrogel films. The solid state 13C NMR, ATR-FTIR and thermal analysis confirmed the formation of ester crosslinks in between CMC and PEG in the hydrogel films. The release of KTZ was found to be retarded due to presence of grafted PEG in the hydrogel films. The hydrogel films exhibited excellent hemocompatibility and cytocompatibility. Implantation test revealed that the hydrogel films caused minimum inflammation. From the overall results, citric acid crosslinked CMC-PEG hydrogel films were found to be suitable for enhanced loading and controlled release of the poorly soluble drugs.

Citric acid crosslinked ß-cyclodextrin/carboxymethylcellulose hydrogel films for controlled delivery of poorly soluble drugs.

Citric acid crosslinked ß-cyclodextrin-carboxymethylcellulose (ßCD-CMC) hydrogel films were prepared by esterification-crosslinking method for the controlled release of ketoconazole (model drug). The hydrogel films were evaluated for active ßCD content, carboxyl content, swelling ratio, drug loading and release, and hemolytic activity. The structural characterization was carried out using solid state 13C NMR, ATR-FTIR, TGA and DSC analysis. The ßCD-CMC hydrogel films showed increase in active ßCD content swelling ratio and drug loading with increase in the concentration of ßCD in the feed. The ßCD helped to minimize the burst effect and retarded the release of ketoconazole. The hydrogel films were found to be biocompatible and capable of controlling the release of ketoconazole for long duration.

Citric acid crosslinked cyclodextrin/hydroxypropylmethylcellulose hydrogel films for hydrophobic drug delivery.

The present communication deals with preparation of ß-cyclodextrin (ßCD) grafted hydroxypropylmethylcellulose (HPMC) hydrogel films using citric acid as crosslinking agent with the aim of improving the loading and achieving controlled release of hydrophobic weak base (ketoconazole). The hydrogel films were characterized by attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy, solid state 13C-nuclear magnetic resonance (13C NMR) spectroscopy, thermal analysis and scanning electron microscopy (SEM). The films were evaluated for ßCD content, carboxyl content, swelling ratio, drug loading, drug release and hemolytic assay. ATR-FTIR spectra indicated crosslinking via ester formation whereas 13C NMR, thermal analysis and SEM confirmed ßCD grafting. The ßCD grafted hydrogel films with high carboxyl content showed maximum swelling and high drug loading. The presence of grafted ßCD helped to retard the release of ketoconazole from the hydrogel films. The hemolytic assay suggested the biocompatible nature of the hydrogel films. Altogether, ßCD grafted HPMC hydrogel films were found to be suitable for delivery of poorly soluble weak bases.