Preparation, Swelling Kinetics And Drug Loading Studies Of Cross Linked Polymeric Hydrogel Beads
Co-polymeric hydrogel beads of 2-hydroxy ethyl methacrylae (HEMA) and methyl methacrylic acid (MMA) polymers using four different cross linking agents like EGDMA, DEGDMA,TriEGDMA and TEGDMA were synthesized and characterized by FTIR and DSC studies. Particle size distribution, shape and surface texture studies were conducted by microscopic methods. The 'nd' values subjected to ANOVA indicated no significant influence of the cross-linking agents used in different concentrations. Dynamic swelling studies of polymeric beads conducted in water, methanol and water-methanol mixture (1:1) suggests that the type of cross-linking agents used have very great impact on the permeation of the solvents. The diffussional kinetic exponent (n) values determined for copolymeric hydrogel beads showed a tendency to move towards Fickian transport (close to 0.43) as the hydrophilicity of the cross linking agent increases. Drug loading studies conducted with chlorpheniramine maleate and nifedipine in all batches of co-polymeric beads showed increase in percentage loading of both the drugs in the order of increasing solubility;TriEGDMADEGDMA>EGDMA. Low level of loading with respect to TEGDMA copolymer (highest solubility) is explained based on the mechanism of liquid penetrant transport in a glassy polymer.