Transdermal Drug Delivery in the Pig Skin

Abstract

Transdermal delivery can be accomplished through various mechanisms including formulation optimization, epidermal stratum corneum barrier disruption, or directly by removing the stratum corneum layer. Microneedling, electroporation, a combination of both and also the intradermal injection known as mesotherapy have proved efficacy in epidermal-barrier disruption. Here we analyzed the effects of these methods of epidermal-barrier disruption in the structure of the skin and the absorption of four compounds with different characteristics and properties (ketoprofen, biotin, caffein, and procaine). Swine skin (Pietrain x Durox) was used as a human analogue, both having similar structure and pharmacological release. They were biopsied at different intervals, up to 2 weeks after application. High-pressure liquid chromatography and brightfield microscopy were performed, conducting a biometric analysis and measuring histological structure and vascular status. The performed experiments led to different results in the function of the studied molecules: ketoprofen and biotin had the best concentrations with intradermal injections, while delivery methods for obtaining procaine and caffein maximum concentrations changed on the basis of the lapsed time. The studied techniques did not produce significant histological alterations after their application, except for an observed increase in Langerhans cells and melanocytes after applying electroporation, and an epidermal thinning after using microneedles, with variable results regarding dermal thickness. Although all the studied barrier disruptors can accomplish transdermal delivery, the best disruptor is dependent on the particular molecule.

Potential of mRNA-based vaccines for the control of tick-borne pathogens in one health perspective

“…In addition to murine models, potency studies in pigs and cattle, for example, may have greater applicability and benefit to humans. Moreover, techniques such as biolistics devices for pig skin delivery offer insights for intradermal delivery in humans and vice versa ( 16 ). Furthermore, the existence of shared or similar pathogens, such as influenza viruses, other viruses, parasites, and mycobacteria, among human and animal populations underscores the importance of vaccination strategies.…”

Quantification of skin penetration of caffeine and propylene glycol applied topically in a mixture by tailored multivariate curve resolution‐alternating least squares of depth‐resolved Raman spectra

“…Therefore, a large amount of topically applied hydrophilic CF resides on the skin surface [2] and saturates mainly the outermost SC [29,30]. To solve the problem of permeation through the skin barrier, invasive methods such as microneedling, electroporation, iontophoresis, ultrasound, intradermal injection (including jet injection), and their combination are used to deliver CF into the dermis [31,32]. Alternatively, to provide a transdermal penetration, CF needs to remain in solution, be at a high thermodynamic activity and not crystallize in the SC [2,33], and/or be applied in combination with penetration enhancers [31,34,35], and/or be incorporated in lipophilic vehicle carrier systems, like liposomes [36] or nanoemulsions [32].…”

“…To solve the problem of permeation through the skin barrier, invasive methods such as microneedling, electroporation, iontophoresis, ultrasound, intradermal injection (including jet injection), and their combination are used to deliver CF into the dermis [31,32]. Alternatively, to provide a transdermal penetration, CF needs to remain in solution, be at a high thermodynamic activity and not crystallize in the SC [2,33], and/or be applied in combination with penetration enhancers [31,34,35], and/or be incorporated in lipophilic vehicle carrier systems, like liposomes [36] or nanoemulsions [32]. The transfollicular penetration of CF into the viable epidermis and dermis of porcine skin was shown ex vivo by a combination of microdialysis and selective follicular closure with varnish [37]-the latter method is known for the separate visualization of the follicular and intercellular penetration pathways [38].…”