Effect of Excipients/Solvents on the Barrier Integrity and Topical Drug Delivery across Micropores

The topical and transdermal drug delivery system offers several advantages over conventional drug delivery; non-invasive, patient compliance, avoidance of first-pass metabolism, and sustaining therapeutic drug levels for several days. As a route for drug administration, skin presents a large surface area and can be used for both local and systemic drug delivery. However, the skin forms a formidable barrier protecting the human body from external environmental rigors and excessive water loss, maintaining equilibrium. The skin\u27s barrier properties can be attributed to its unique macromolecular organization and morphology. However, the organized structure of the skin, since intended to prevent the entry of adverse chemicals, poses a formidable challenge to molecular transport. In vitro permeation testing (IVPT) is a great tool to measure the bioavailability of drugs and determine the bio-equivalence between reference and generic drug products. In the first chapter, the influence of formulation ingredients on skin barrier integrity during the IVPT study was evaluated. Alongside, we also investigated the effect of age and aging of the skin on the barrier integrity. We moved from a passive to an active delivery system in the second chapter. In this chapter, we explored the effect of the solvents on drug delivery across the skin pretreated with a metallic microneedle. The hypothesis was that solvent property would significantly influence the recovery dynamics of micropores. This, in turn, would significantly impact the drug delivery across the skin pretreated with a metallic microneedle. Finally, in the third chapter, the passive diffusion of nanoparticle was explored. In this chapter, carbon nanoparticles (CDs) were synthesized and conjugated with lidocaine hydrochloride (LH), and the feasibility of delivering CDs-LH complex topically was demonstrated