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Unique pH-sensitive spray dried microspheres were formulated employing hydrolyzed polyacrylamide-g-carboxymethylcellulose sodium (PAAm-g-NaCMC) co-polymer for colon targeted delivery of an anticancer drug, capecitabine. Synthesis of PAAm-g-NaCMC was carried out through free radical polymerization, which was supported with an inert atmosphere and then the alkaline hydrolysis was performed and subjected for characterization including FTIR spectroscopic analysis, H NMR spectroscopic analysis, elemental analysis, viscosity measurement, neutralization equivalent and thermo-gravimetric investigation. The swelling data suggested that the PAAm-g-NaCMC possesses significant pH-sensitive property. The microspheres were in the range of 1.00 to 7.34 μ and the drug entrapment efficiency ranged between 70.98 and 94.41%. In vitro drug release suggested the failure of microspheres formulated using native NaCMC which failed to impede drug release in stomach and small intestine, while those prepared with pH-sensitive PAAm-g-NaCMC copolymer and cross-linked with glutaraldehyde are suitable for colon targeting because they retarded release of drug in physiologic atmosphere of stomach and small intestine. Only 12.97% of drug was released from CMC10 formulation by the end of 5th h and rest of drug has been targeted to colonic region. A sudden increase in release of drug was observed in rat caecal contents media because of colonic bacterial action on PAAm-g-NaCMC copolymer.

Objective: The study aimed to prepare electrically-triggered transdermal drug delivery systems (ETDS) using electrically responsive polyacrylamide-graft-gaur gum (PAAm-g-GaG) copolymer. Methods: The PAAm-g-GaG copolymer was synthesized by adopting free radical polymerization grafting method. This PAAm-g-GaG copolymer hydrogel acts as a drug reservoir and blend films of Guar Gum (GaG) and Polyvinyl Alcohol (PVA) were included as Rate Controlling Membranes (RCM) in the system. The PAAm-g-GaG copolymer was characterized by FTIR, neutralization equivalent values, thermogravimetric analysis and elemental analysis. Results: On the basis of results obtained, it is implicit that the drug permeation decreased with an increase in the concentration of glutaraldehyde and RCM thickness; while drug permeation rate was increased with increasing applied electric current strength from 2 to 8 mA. A two fold increase in flux values was observed with the application of DC electric current. An increase in drug permeation was witnessed under on condition of electric stimulus and permeation was decreased when electric stimulus was "off". The skin histopathology study confirmed the changes in skin structure when electrical stimulus was applied. Conclusion: The electrically-sensitive PAAm-g-GaG copolymer is a useful biomaterial for transdermal drug delivery application.