Even though there was no significant difference between the viscosity of GPSY and GTPSY, the GTPSY provided a prolonged release selleck of metronidazole. This could be due to the in situ cross-linking exhibited by disulfide linkages of thiolated polymer. The commercial formulation Metrogyl provided a prolonged release over a period of 24h. However, by optimizing the concentration of GTPSY and the degree of thiolation a gel formulation with desired release characteristics can be easily formulated. Figure 5In vitro release profile of metronidazole from GPSY, GTPSY, and Metrogyl gel.The release of metronidazole loaded gels and marketed formulations was fitted into various kinetic models to estimate their release kinetics and mechanism of release (Table 2).

The results of release rate data for all the gel formulations fitted best into first-order release kinetics. Further, the value of ��n,�� the release exponent of Korsmeyer and Peppas equation, indicates that the release of metronidazole from GPSY and GTPSY (n > 0.5) occurs by combination of polymer relaxation and diffusion through the polymeric matrix while the release from commercial formulation occurs by diffusion through the matrix [12].Table 2Modeling and release kinetics of metronidazole gel formulations. 4. ConclusionsThiol modification of psyllium was carried out by esterification with thioglycolic acid. Thiolated psyllium was characterized by FT-IR, DSC, XRD, and SEM study. Modified psyllium was employed for formulating mucoadhesive gels using metronidazole as the model drug.

Thiolation of psyllium resulted in 3-fold increase in its mucoadhesive strength and 1.5-fold increase in mucoadhesion retention time. The results of in vitro release study indicate that thiolation of psyllium imparts sustained release characteristics without affecting its viscosity. In conclusion, thiol modification of psyllium improves its mucoadhesive properties.AcknowledgmentsThe authors are thankful to SAIF, Panjab University, Chandigarh, for providing facilities for SEM analysis and UGC for financial grants under UGC Major Research Project.
It is well known that azo dyes are recalcitrant and toxic contaminants to aquatic organisms and carcinogenic and mutagenic to humans [1]. Therefore, in order to avoid the environmental problems caused by these pollutants and their hazardous effects on living beings, it is necessary to find technologies that effectively remove azo dyes from textile wastewater before discharging this effluent into the water resources.

Many researchers have evaluated the effectiveness of several types of low-cost biomaterials, such as chitosan [2], cellulose [3], and Rhizopus oryzae [4], for the removal of various dyes. Chitosan, poly (1��4)-2 amino-2-deoxy-��-D-glucan, is usually obtained from waste biomass during seafood processing and mainly Drug_discovery comprises shells of crabs, shrimp, prawns, and krill [5].