Dermatokinetics: Advances and Experimental Models, Focus on Skin Metabolism

Complexin vitromodels positioned for impact to drug testing in pharma: a review

Recent years have seen the creation and popularization of various complexin vitromodels (CIVMs), such as organoids and organs-on-chip, as a technology with the potential to reduce animal usage in pharma while also enhancing our ability to create safe and efficacious drugs for patients. Public awareness of CIVMs has increased, in part, due to the recent passage of the FDA Modernization Act 2.0. This visibility is expected to spur deeper investment in and adoption of such models. Thus, end-users and model developers alike require a framework to both understand the readiness of current models to enter the drug development process, and to assess upcoming models for the same. This review presents such a framework for model selection based on comparative -omics data (which we term model-omics), and metrics for qualification of specific test assays that a model may support that we term context-of-use (COU) assays. We surveyed existing healthy tissue models and assays for ten drug development-critical organs of the body, and provide evaluations of readiness and suggestions for improving model-omics and COU assays for each. In whole, this review comes from a pharma perspective, and seeks to provide an evaluation of where CIVMs are poised for maximum impact in the drug development process, and a roadmap for realizing that potential.

Mesoporous Silica-Based Membranes in Transdermal Drug Delivery: The Role of Drug Loss in the Skin

Compared to other forms of drug administration, the use of Transdermal Drug Delivery Systems (TDDSs) offers significant advantages, including uniform drug release profiles that contribute to lower side effects and higher tolerability, avoidance of direct exposure to the gastrointestinal tract, better patient compliance due to their non-invasive means of application and others. Mesoporous silica membranes are of particular interest in this regard, due to their chemical stability and their tunable porous system, with adjustable pore sizes, pore volumes and surface chemistries. While this allows for fine-tuning and, thus, the development of optimized TDDSs with high loading capacities and the desired release profile of a given drug, its systemic availability also relies on skin penetration. In this paper, using a TDDS based on mesoporous silica membranes in Franz cell experiments on porcine skin, we demonstrate surprisingly substantial drug loss during skin penetration. Drug passage through porcine skin was found to be dependent on the age and pre-treatment of the skin. pH and temperature were major determinants of drug recovery rates as well, indicating drug loss in the skin by enzymatic metabolization. Regarding the TDDS, higher loading obtained by SO3H surface modification of the mesoporous silica membranes reduced drug loss. Still, high loss rates in the skin were determined for different drugs, including anastrozole, xylazine and imiquimod. We conclude that, beyond the fine-tuned drug release profiles from the mesoporous silica membrane TDDS, remarkably high drug loss in the skin is a major issue for achieving desired skin penetration and, thus, the systemic availability of drugs. This also poses critical requirements for defining an optimal TDDS based on mesoporous silica membranes.

Cutaneous Pharmacokinetics of Topically Applied Novel Dermatological Formulations

Novel formulations are developed for dermatological applications to address a wide range of patient needs and therapeutic challenges. By pushing the limits of pharmaceutical technology, these formulations strive to provide safer, more effective, and patient-friendly solutions for dermatological concerns, ultimately improving the overall quality of dermatological care. The article explores the different types of novel dermatological formulations, including nanocarriers, transdermal patches, microsponges, and microneedles, and the techniques involved in the cutaneous pharmacokinetics of these innovative formulations. Furthermore, the significance of knowing cutaneous pharmacokinetics and the difficulties faced during pharmacokinetic assessment have been emphasized. The article examines all the methods employed for the pharmacokinetic evaluation of novel dermatological formulations. In addition to a concise overview of earlier techniques, discussions on novel methodologies, including tape stripping, in vitro permeation testing, cutaneous microdialysis, confocal Raman microscopy, and matrix-assisted laser desorption/ionization mass spectrometry have been conducted. Emerging technologies like the use of microfluidic devices for skin absorption studies and computational models for predicting drug pharmacokinetics have also been discussed. This article serves as a valuable resource for researchers, scientists, and pharmaceutical professionals determined to enhance the development and understanding of novel dermatological drug products and the complex dynamics of cutaneous pharmacokinetics.