Preparation and characterization of amidated pectin based hydrogels for drug delivery system.

In the current studies attempts were made to prepare hydrogels by chemical modification of pectin with ethanolamine (EA) in different proportions. Chemically modified pectin products were crosslinked with glutaraldehyde reagent for preparing hydrogels. The hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), organic elemental analysis, X-ray diffraction studies (XRD), swelling studies, biocompatibility and hemocompatibility studies. Mechanical properties of the prepared hydrogels were evaluated by tensile test. The hydrogels were loaded with salicylic acid (used as a model drug) and drug release studies were done in a modified Franz's diffusion cell. FTIR spectroscopy indicated the presence of primary and secondary amide absorption bands. XRD studies indicated increase in crystallinity in the hydrogels as compared to unmodified pectin. The degree of amidation (DA) and molar and mass reaction yields (YM and YN) was calculated based on the results of organic elemental analysis. The hydrogels showed good water holding properties and were found to be compatible with B-16 melanoma cells & human blood.

Biomedical evaluation of polyvinyl alcohol-gelatin esterified hydrogel for wound dressing.

The wound is a biosynthetic environment in which numerous cellular processes are interlinked in the process of repair. Modern dressings are designed to facilitate wound healing rather than just to cover it. Hydrogel dressing can protect injured skin and keep it appropriately moist to speed the healing process by absorbing exudates while maintaining the products of tissue repair, including growth factor and lysosomes, in contact with the wound. The design and development of novel membrane of hydrogels prepared by esterification of polyvinyl alcohol with gelatin were attempted. Contact angle of goat blood was determined. The hydrogel was characterized by hemolysis test and water vapor transmission rate. Diffusion coefficient of salicylic acid (SA) and gatifloxacin, a fourth generation fluoroquinolone, through the membrane was determined. Both the drugs were used as model drug. Methyl tetrazolium dye assay of the membrane was done using L929 fibroblast cell line and mice splenocytes to establish the biocompatibility of the membrane. The equilibrium goat blood-in-air contact angles of measured ester films ranged from 56 to 60 degrees . The hydrogel was found to be hemocompatible and moisture retentive indicating its possible use in moist wound care. The diffusion coefficient of SA and gatifloxacin through the membrane was found to be 1.49 x 10(-5) and 3.97 x 10(-6) cm(2)/s respectively. The membrane was found to be compatible with the L929 fibroblast cell line and mice splenocytes.

Analysis and characterization of alumina particles reinforced ultra high molecular weight polyethylene composite for acetabular cup.

Composites of ultra high molecular weight polyethylene (UHMWPE) reinforced with 5, 10 and 15 percent of alumina were prepared by a technique of uniform mixing and moulding. Acetabular cups were produced by compression moulding methods. A new walk simulator was also developed in-house for testing the tribological performances of these cups. The results from walk simulator tests are encouraging. Using a human walk simulator machine we did in vitro wear testing. Characterizations were performed to analyse the microstructure, composition, phase purity and crystalline by using XRD, DSC/TGA. Biocompatibility test was done by cytotoxicity, hemocompatibility and MTT assay methods. Biocompatibility tests gave hemolysis counts with these polymer composites well within the acceptable range and the results indicate a significant improvement in biocompatibility of the polymer composites over the in parent polymers.

Amidated pectin based hydrogels: synthesis, characterization and cytocompatibility study.

The design and development of pectin-based hydrogels were attempted through the chemical modification of pectin with diethanolamine (DA). Diethanolamine modified pectin (DAMP) was synthesized by the chemical modification of pectin with varying concentrations of DA (1:1,1:2,1:3 and 1:4) at 5 oC in methanol. The modified product was used for the preparation of the hydrogel with glutaraldehyde (GA) reagent. The prepared hydrogels were characterized by Fourier transform infrared (FTIR) spectroscopy; organic elemental analysis, and X-ray diffraction (XRD), and swelling, hemocompatibility and cytocompatibility studies of the prepared hydrogels were also done. FTIR spectroscopy indicated the presence of primary and secondary amide absorption bands. The XRD pattern of the DAMP hydrogel clearly indicated that there was a considerable increase in crystallinity as compared to parent pectin. The degree of amidation (DA) and molar and mass reaction yields (Ym and Yn) was calculated based on the results of organic elemental analysis. Drug release studies from the hydrogel membranes were also evaluated in a Franz's diffusion cell. The hydrogels demonstrated good water holding properties and were found to be compatible with B-16 melanoma cells and human blood.

Polyvinyl alcohol--gelatin patches of salicylic acid: preparation, characterization and drug release studies.

Polyvinyl alcohol-gelatin patches were developed and salicylic acid was incorporated at different stages of preparation of the patches. The patches were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry, tensile strength test, and scanning electron microscopy. The release patterns of the drug from the patches were also studied. The FTIR spectra of the blank patch indicated complete esterification of the free carboxylic groups of gelatin. The XRD studies indicated a crystalline form of the drug entrapped in the patches. Release of the drug from the patches followed Higuchian/Fickian kinetics indicating a diffusion-controlled release process.

Characterization of prepared corn starch-based hydrogel membranes.

The design and development of novel hydrogel membranes prepared by crosslinking polyvinyl alcohol with heat-treated cornstarch (CS) and CS suspensions was attempted. Degradation studies of the hydrogel membranes were conducted using á -amylase. The mechanical property of the hydrogel membranes was characterized by tensile tests. The swelling behavior of the membranes was also evaluated. Methyl tetrazolium assay of the membranes was performed using mice splenocytes and the L929 cell line to establish cytocompatibility. The membranes had sufficient strength and water holding capacity. The membrane was found to be biocompatible with L929 fibroblast cells and mice splenocytes.

Development of carboxymethyl cellulose acrylate for various biomedical applications.

The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material.