A Comparison of Drug Delivery into Skin Using Topical Solutions, Needle Injections and Jet Injections

Abstract

Drug diffusion within the skin with a needle-free micro-jet injection (NFI) device was compared with two well-established delivery methods: topical application and solid needle injection. A permanent make-up (PMU) machine, normally used for dermal pigmentation, was utilized as a solid needle injection method. For NFIs a continuous wave (CW) laser diode was used to create a bubble inside a microfluidic device containing a light absorbing solution. Each method delivered two different solutions into ex-vivo porcine skin. The first solution consisted of a red dye (direct red 81) and rhodamine B in water. The second solution was direct red 81 and rhodamine B in water and glycerol. For PMU experiments, the skin samples were kept stationary and the diffusion depth, width and surface area were measured. The NFI has a higher vertical dispersion velocity of 3 × 10 5 /s compared to topical (0.1 µm/s) and needle injection (53 /s). The limitations and advantages of each method are discussed, and we conclude that the micro-jet injector represents a fast and minimally invasive injection method, while the solid needle injector causes notably tissue damage. In contrast, the topical method had the slowest diffusion rate but causes no visible damage to the skin.

Transdermal Delivery of Photosensitizer‐Catalase Conjugate by Fluorinated Polyethylenimine for Enhanced Topical Photodynamic Therapy of Bacterial Infections

“…[24] As the preferred route for treatment of skin diseases including dermatitis, microbial infections, as well as inflammation, dermal and transdermal drug administration could offer a larger available drug absorption area and facilitate self-managed, pain-free application with better patient compliance. [25][26][27][28][29][30] However, considering the existence of the stratum corneum barrier that limits the penetration of drugs through the skin, only a small number of drugs with small molecular weights can be transdermally delivered through the skin. [31][32][33][34] The effective transdermal drug delivery (TDD) of drugs with poor, large molecular weight (e.g., protein therapeutics) remains a significant challenge.…”