Innovative Strategies for Enhancing Topical and Transdermal Drug Delivery

Abstract

Abstact: Historically, the skin was thought to be a simple homogenous barrier. However, it is now known to be a highly specialised organ, and plays a key role in homeostasis. The protective properties of the skin are provided by the outermost layer, the epidermis, which safeguards against chemical, microbial, and physical attack. The exceptional barrier properties of the skin result in it being a challenging route for the delivery of therapeutic agents. This article reviews strategies developed to enhance the skin penetration of drugs, ranging from conventional approaches, for example the use of chemical penetration enhancers to those in early-stage development, such as microscissioning.

Physical characterization and in vitro skin permeation of solid lipid nanoparticles for transdermal delivery of quercetin

“…This layer is composed of corneocytes, which are dead keratinocytes, and a lipid matrix surrounding the corneocytes. It forms a sturdy protecting barrier by preventing inflow of external harmful material into the body and also acts as penetration barrier by blocking the delivery of active ingredients into the skin [14][15][16]. Therefore, development of a robust skin delivery system is required to enhance the delivery of active ingredients.…”

Effect of Lipophilicity on Microneedle-Mediated Iontophoretic Transdermal Delivery Across Human Skin In Vitro

“…Further, skin being negatively charged at the physiological pH, it possesses perm-selectivity toward positively charged molecules. [32][33][34][35] SC gets breached upon treatment with MN, and this affects its perm-selectivity, which in turn could affect the iontophoretic flux. 33 The outcome of this study addresses this key issue and provides an insight into the versatility of this combination approach for enhancing the transdermal delivery of molecules.…”

Alkylglycerol Derivatives, a New Class of Skin Penetration Modulators

“…Collectively, both enhancers and retarders are known as penetration modifiers [5]. Although the mechanisms of action of retarders have not been completely understood, it has been proposed that they may act (i) as antisolvents, by avoiding the partitioning of the drug into the SC; (ii) by adding lipid-like molecules into the lipid bilayers to stiffen the SC [6]; (iii) by providing order to the lipid–lipid arrangement in the SC and then decreasing the diffusion coefficient of the drug [5]. Two decades ago, Hadgraft et al [4] conducted a study that examined the effect of Azone ® and five derivatives on the permeation of m-diethyltoluamide and metronidazole through the skin.…”