RESUMO
Pectin grafted polyacrylic copolymer hydrogels were made by free radical crosslink copolymerization of acrylic acid (AA) and acrylamide (AM) in an aqueous solution of pectin. N'N-methylene bis acrylamide (MBA) was used as a crosslinker. During the polymerization reaction the attapulgite (APG) filler was also incorporated in situ into the network of the copolymer gel. Several filled hydrogels were prepared by varying the amount of pectin and APG filler. These hydrogels were characterized by FTIR, 13C NMR, XRD, TGA, SEM, mechanical properties, DMA, swelling, diffusion characteristics and network parameters. The release kinetics of a model drug diltiazem hydrochloride (DT) was studied with these hydrogels. The wt% of pectin, APG and MBA was optimized with a central composite design (CCD) model of response surface methodology (RSM) with equilibrium swelling ratio (ESR), drug adsorption (mg/100 mg gel) and drug release% in 16 h as response. Accordingly, the hydrogel prepared with 5:1 AA:AM molar ratio, 25 wt% monomer concentration, 1% each of initiator and MBA concentration, 18 wt% pectin and 2 wt% APG showed an optimized ESR of 17.75, drug loading of 27.58 and a drug release % of 92.5 in 16 h at a solution pH of 7.4.
Assuntos
Resinas Acrílicas/química , Diltiazem/farmacologia , Géis/química , Compostos de Magnésio/química , Pectinas/química , Compostos de Silício/química , Adsorção , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Preparações de Ação Retardada/farmacologia , Difusão , Liberação Controlada de Fármacos , Hidrogéis/química , Concentração de Íons de Hidrogênio , Cinética , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Fatores de Tempo , Difração de Raios XRESUMO
Several composite hydrogels were synthesized by free radical crosslink copolymerization of acrylic acid (AA) and N' methylene bis-acrylamide (MBA) in the presence of chitosan (CS). During polymerization CS was incorporated in situ in the crosslinked polyacrylic acid gel to produce composite hydrogels. The structure and properties of the hydrogels were characterized by FTIR, (13)C NMR, DTA-TGA, XRD, swelling and diffusion characteristic and also network parameters. The loading and the in vitro release behaviours of theophylline and tinidazole model drugs were studied with these hydrogels. The wt% of CS and MBA and pH of the medium was found to strongly influence the drug release behaviour of the gels. Accordingly, the release rate of these two drugs was much faster at pH of 7.6 than at pH 1.5.
Assuntos
Acrilatos/química , Quitosana/química , Preparações de Ação Retardada , Portadores de Fármacos/química , Hidrogéis/administração & dosagem , Teofilina/administração & dosagem , Tinidazol/administração & dosagem , Alquilantes/administração & dosagem , Alquilantes/química , Broncodilatadores/administração & dosagem , Broncodilatadores/química , Varredura Diferencial de Calorimetria , Difusão , Hidrogéis/química , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Espectroscopia de Infravermelho com Transformada de Fourier , Teofilina/química , Tinidazol/química , Difração de Raios XRESUMO
Several semi interpenetrating network (SIPN) type hydrogels were synthesized by in-situ free radical crosslink copolymerization of acrylamide and crosslinker N,N'-methylene bisacrylamide (MBA) in aqueous solution of sodium alginate (SA).These SIPN hydrogels were characterized by FTIR, NMR SEM, DTA-TGA, XRD, PZC and also by swelling characteristics and network parameters. Adsorption (loading) and release of acetaminophen drug were studied with these hydrogels. Solution pH, crosslinker concentration and monomer to SA weight ratio of the hydrogels were found to have a strong effect on adsorption and in vitro release profile of the drug from the gel matrix.
