In this perspective article, the basic theory and applications of the "Quantum Theory of Atoms in Molecules" have been presented with examples from different categories of weak and hydrogen bonded molecular systems.

Background and Objectives: To develop electro-sensitive transdermal drug delivery systems (ETDDS) using polyacrylamide-grafted-pectin (PAAm-g-PCT) copolymer hydrogel for rivastgimine delivery. Methods: Free radical polymerization and alkaline hydrolysis technique was employed to synthesize PAAm-g-PCT copolymer hydrogel. The PAAm-g-PCT copolymeric hydrogel was used as reservoir and cross-linked blend films of PCT and poly(vinyl alcohol) as rate controlling membranes (RCMs) to prepare ETDDS. Results: The pH of hydrogel reservoir was found to be in the range of 6.81 to 6.93 and drug content was 89.05 to 96.29%. The thickness of RCMs was in the range of 51 to 99 µ and RCMs showed permeability behavior against water vapors. There was a reduction in water vapor transmission rate as the glutaraldehyde (GA) concentration was increased. The drug permeation rate from the ETDDS was enhanced under the influence of electric stimulus against the absence of electric stimulus. The increase in flux by 1.5 fold was recorded with applied electric stimulus. The reduction in drug permeability observed when the concentration of GA was increased. Whereas, the permeability of drug was augmented as electric current was changed from 2 to 8 mA. The pulsatile drug release under “on–off” cycle of electric stimulus witnessed a faster drug release under ‘on’ condition and it was slow under ‘off’ condition. The alteration in skin composition after electrical stimulation was confirmed through histopathology studies. Conclusion: The PAAm-g-PCT copolymer hydrogel is a useful carrier for transdermal drug delivery activated by an electric signal to provide on-demand release of drugs.

No abstract

No abstract