Neem gum based pH responsive hydrogel matrix: A new pharmaceutical excipient for the sustained release of anticancer drug.

The present research work was aimed to synthesize neem gum-based site-specific drug delivery device for anticancer drug methotrexate at different pH condition. The hydrogel-based drug delivery device was synthesized by optimizing reaction parameters using a factorial design approach response surface method. This model comprised of various sets of reactions with varying concentrations of solvent, crosslinker, initiator and monomer under microwave radiation. Characterization of the candidate hydrogel was done using UV-visible spectrophotometer, FTIR, SEM, Raman, and XRD techniques. The release profile of the hydrogels network was studied through a methotrexate under different pH conditions. The drug encapsulation capacity was found to be around 93% and 90% in pH 7.4 and 6.8. Drug release through the synthesized hydrogel matrix was found to show non-Fickian behaviour at each medium. The hydrogel network showed less release in pH 6.8 than pH 7.4, suggesting that hydrogels may be suitable drug carriers for release of anticancer drug delivery system. Hemolysis testing was also done to check the compatibility of the synthesized drug delivery device with the four different blood samples. Hemolysis was found to be less than 1% in the case of all blood groups, which indicates that the synthesized candidate polymers are biocompatible with all blood groups.

RSM-CCD optimized sodium alginate/gelatin based ZnS-nanocomposite hydrogel for the effective removal of biebrich scarlet and crystal violet dyes.

The present work represents RSM-CCD (Response Surface Methodology integrated Central composite Design) optimized synthesis scheme of semi-IPN (semi interpenetrating network) NaAla-Gel-cl-polyAAm and ZnS nanocomposite adsorbent NaAla-Gel-cl-polyAAm/ZnS. Under optimized reaction parameters semi-IPN NaAla-Gel-cl-polyAAm showed maximum swelling percentage of 3191.73%. Maximum dye removal percentage (97.37%) was observed with ZnS nanocomposite for the removal of biebrich scarlet. The adsorption isotherm data indicated that Langmuir and Freundlich adsorption isotherm fitted well for biebrich scarlet (R2 = 0.964) and crystal violet (R2 = 0.960), respectively. ΔG°, ΔH° and ΔS° values indicated the thermodynamic feasibility of the reaction. Excellent recyclability and reusability of the adsorbent materials suggested their applicability towards textile industry and water purification purpose.

Response surface methodology directed synthesis of luminescent nanocomposite hydrogel for trapping anionic dyes.

The present research work reveals semi-interpenetrating network (semi-IPN) synthesis using response surface methodology-central composite design (RSM-CCD) based optimization. The maximum swelling of 362.11% was obtained with monomer, crosslinker and initiator concentrations 4.39 mol L-1, 1.52 mol L-1 and 4.58 mol L-1, respectively, temperature 70 °C, time 3 h and pH 4.0. The synthesized hydrogel showed 94.16% and 95.62% removal for eosin yellow (EY) and eriochrome black-T (EBT) dyes, respectively. The incorporation of cadmium sulphide nanodots into the hydrogel network enhanced the % dye removal (96.82% EY and 98.73% EBT) along with fluorescent behavior. Various conditions optimized for EY and EBT dye removal with respect to semi-IPN were: 0.4 g adsorbent dose each, dye concentrations 10 mg L-1 and 120 mg L-1, contact time 24 h each, respectively. Adsorption studies followed langmuir theory for both dyes. Second order and first order kinetics along with intraparticle diffusion of dye molecules were favorable to EY and EBT, respectively. Thermodynamic study reveals exothermic nature of adsorption. Recyclability of the adsorbent is superior as tested by desorption-adsorption tests.

Selective removal of cationic dyes using response surface methodology optimized gum acacia-sodium alginate blended superadsorbent.

Gum acacia and sodium alginate were blended to synthesize highly efficient superadsorbent formed by grafting of poly(acrylic acid) (AA) used as monomer onto the hybrid of gum acacia and sodium alginate and the polymeric chains were crosslinked through N,N'-methylene bisacrylamide (MBA). The overall reaction followed free radical polymerization with ammonium persulphate (APS) used as initiator. Response surface methodology integrated with central composite design (RSM-CCD) could synthesize semi-Interpenetrating network (semi-IPN) having maximum swelling capacity of 1749.2% at MBA, APS and AA concentrations of 0.89 × 10-2 mol L-1, 3.29 × 10-2 mol L-1 and 1.46 mol L-1, respectively using 15 mL water at 70 °C for 2.5 h. The synthesized sample was found to be selective for removal of cationic dyes upto 97.49%, 95.39% and 94.56% for auramine-O (AO), malachite green (MG) and crystal violet (CV), respectively. Adsorption capacities at equilibrium were calculated experimentally as 2.01 mg g-1, 3.06 mg g-1 and 7.55 mg g-1 for AO, MG and CV, respectively. These dyes could be desorbed with 0.1 N HCl for the recyclization of semi-IPN. Adsorption mechanism involved monolayer formation with three step process of adsorption and followed first order kinetics. Exothermic nature of adsorption was revealed by thermodynamic studies.

Efficient capture of eosin yellow and crystal violet with high performance xanthan-acacia hybrid super-adsorbent optimized using response surface methodology.

Blending of xanthan and acacia gives a unique hybrid that was used for the synthesis of semi-interpenetrating network (semi-IPN) in which poly(acrylamide) chains were grafted onto hybrid of xanthan-acacia followed by their cross-linking (Xan-Aca-cl-poly(AAm)). Optimization was carried out under response surface methodology-central composite design (RSM-CCD). Maximum percentage swelling of semi-IPN obtained was 496.57%. The concentrations of acrylamide, citric acid and ammonium persulphate used as monomer, cross-linker and initiator, respectively were found to be significant parameters. The blend was highly effective in removal of both cationic (crystal violet) and anionic dyes (eosin yellow) showing maximum dye removal capacity of 97.58% and 95.42%, respectively under optimized parameters - 0.4 g semi-IPN dose in 15 ml dye solution of 10 mg L-1 concentration within 16 h. Adsorption mechanism of both the dyes followed three steps in accordance with intraparticle diffusion model along with mono layer langmuir adsorption criteria. Second order kinetics was followed in case of both dyes. Thermodynamic studies gave idea about the exothermic nature of adsorption. Semi-IPN could be recycled up to eight consecutive cycles and hence, can be utilized for industrial purpose for removal of dyes.

Sequestration of dyes from artificially prepared textile effluent using RSM-CCD optimized hybrid backbone based adsorbent-kinetic and equilibrium studies.

Present work reports the synthesis of semi-Interpenetrating Network Polymer (semi-IPN) using Gelatin-Gum xanthan hybrid backbone and polyvinyl alcohol in presence of l-tartaric acid and ammonium persulphate as the crosslinker-initiator system. Reaction parameters were optimized with Response Surface Methodology (RSM) in order to maximize the percent gel fraction of the synthesized sample. Polyvinyl alcohol, l-Tartaric acid, ammonium persulphate, reaction temperature, time and pH of the reaction medium were found to make an impact on the percentage gel fraction obtained. Incorporation of polyvinyl alcohol chains onto hybrid backbone and crosslinking between the different polymer chains were confirmed through techniques like FTIR, SEM-EDX and XRD. Semi-IPN was found to be very efficient in the removal of cationic dyes rhodamine-B (70%) and auramine-O (63%) from a mixture with an adsorbent dose of 700 mg, initial concentration of rhodamine-B 6 mgL-1 and auramine-O 26 mgL-1, at an time interval of 22-25 h and 30 °C temp. Further to determine the nature of adsorption Langmuir and Freundlich adsorption isotherm models were studied and it was found that Langmuir adsorption isotherm was the best fit model for the removal of mixture of dyes. Kinetic studies for the sorption of dyes favored the reaction mechanism to occur via a pseudo second order pathway with R2 value about 0.99.