Nirmal K. Patel

Synthesis, Characterization and Optimization of Water-Soluble Chitosan Derivatives

Chitosan was chemically modified using monochloroacetic acid at various reaction conditions. Chemical structure was confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The carboxymethyl chitosan (CM-chitosan) was prepared at different temperatures, water/isopropanol (IPA) ratios and alkali concentrations. Reaction conditions have great influence on the degree of substitution (DS) and, in turn, the solubility. The water solubility of chitosan derivatives depended upon modification conditions and degree of substitution.

Synthesis and characterization of Sodium salt of partially carboxymethylated starch

Sodium salt of partially carboxymethylated starch (Na-PCMS) was prepared in a completely heterogeneous process in an isopropyl water slurry and the influence of the reaction conditions on the degree of substitution (DS) was checked. The concentration of aqueous sodium hydroxide solution, which was used to activate the starch, was varied in the range from 8 to 30% Wt, reaction time from 2 to 6 hr at 55°C. The reaction with sodium monochloroacetate leads to the highest degree of substitution of 1.24 at a NaOH concentration of 15% and 5 hr reaction time. Using a lye concentration of 30% no influence of the reaction time between 2 hr and 6 hr was found. From FTIR spectroscopical studies it was concluded that all the samples were Na-PCMS.

Preparation, characterization and antimicrobial activity of acrylate copolymer bound amoxycillin

Alternate copolymers of n-butyl methacrylate and maleic anhydride were prepared and characterized. Amoxycillin was bound on copolymers through pendent anhydride groups by chemical bonding. In vitro release rates were investigated in 0.1 M phosphate buffer solution with varying pH at 37 0 as well as in biological media. The release rates of the investigated model drug molecules followed first order kinetics and were dependent on buffer concentration and pH. It was observed that molecular weight of copolymers varied from 8000 to 22,000 g/mol and duration of the delay period prior to release increased from 6 to 9 d. P(BMA-MA-1) showed increase in cumulative release rate with increase in pH unit from 3.8 to 7.2, which further decreased from pH 7.8 and 8.0, respectively. With P(BMA-MA-2) gradual increase in release activity was observed in acidic range and in neutral to alkaline condition (pH 7.0 to 8.0) the release activity lasted for 7 to 9 d respectively. Similar condition for P(BMA-MA- 3) showed cumulative release activity for 9 d in acidic pH, which further decreased to 7 d from pH 7.0 to 8.0. P(BMA-MA-1, 2 and 3) showed maximum inhibition of 40%, 59.3% and 72.8% towards Bacillus subtilis, 40%, 44% and 65.4% inhibition against Staphylococcus aureus and 41.2%, 51.7% and 69.1% inhibition against Escherichia coli at 48 h of incubation.

Synthesis, Characterization and Biodegradation of Low Density Polyethylene [LDPE] and Partially Carboxymethylated Starch [PCMS] Blend

ABSTRACT Sodium salts of partially carboxymethylated starch (Na-PCMS) with degree of substitution (DS) 0.21, 0.314, 0.58 and 1.10 were synthesized from starch. These starch ethers were blended with low density polyethylene (LDPE) in various proportions using brabender mixer. Effect of DS on compatibility of the blend was studied by monitoring the change in mechanical properties. The blend having optimum properties was studied for the growth of Bacillus species (BS) and degradation by means of weight loss and change in tensile strength as well as percent elongation. The morphological change in blend was studied by scanning electron microscopy.

Biodegradable Composition Based on Low Density Polyethylene

ABSTRACT Sodium salt of partially carboxymethylated starch (Na-PCMS) with degree of substitution DS 0.58 and starch acetate with DS 1.7 were synthesized from starch. These starch ethers and acetates along with starch, poly(vinyl acetate) (PVAc) and poly(vinyl alcohol) (PVA) were blended with low density polyethylene (LDPE) in various proportion using Brabender mixer. Addition of 5% stearic acid as a plasticizer improves the blend compatibility. Change in mechanical properties were monitored and optimum composition of blend were prepared. This blend was studied for growth of Bacillus species (BS) and degradation by means of weight loss and change in mechanical properties viz., tensile strength and % elongation, and total cellular protein. Degradation of pure polymers within one month period was also examined.

Optimization of reaction parameter to prepare 2-HEMA-g-NaPCMS using CAN as an initiator

Sodium salts of partially carboxymethylated starch-g-poly(hydroxypropyl methacrylate)(Na-PCMS-g-PHPMA) copolymer containing 35-45% PHPMA were prepared using ceric ammonium nitrate (CAN) as an initiator. All the experiments were run with Na-PCMS (DS-1.10). Graft copolymers were characterized with respect to % PHPMA, % total conversion, % grafting, % grafting efficiency and confirmation of grafting was done by infrared spectral analysis. Variables investigated in the graft copolymerization reaction were nitric acid concentration, reaction time, reaction temperature and ceric ion concentration. The results are discussed with illustration.

2-HEMA-g-Na-PCMS: A Novel Polymeric Matrix for the Controlled Release of Paracetamol

2-hydoxyethyl methacrylate (2-HEMA) was graft copolymerized with sodium salt of partially carboxymethylated starch (Na-PCMS). Thus prepared, graft copolymer (2-HEMA-g-Na-PCMS) was used as a polymeric matrix for preparing controlled-release tablets of paracetamol. Tablets of standard specification were prepared using the wet granulation method. Ingredients utilized for tablet preparation were 2-HEMA-g-Na-PCMS graft copolymer, paracetamol and excipients. Tablets were characterized for disintegration time (min), hardness, angle of repose and percent friability. It was found that tablets prepared by the compression of graft copolymer, excipients and drug in specified ratios resulted in an excellent controlled-release tendency of paracetamol.