Evaluation of the percutaneous absorption of chlorpromazine from PLO gels across porcine ear and human abdominal skin

An update of skin permeability data based on a systematic review of recent research

The cutaneous absorption parameters of xenobiotics are crucial for the development of drugs and cosmetics, as well as for assessing environmental and occupational chemical risks. Despite the great variability in the design of experimental conditions due to uncertain international guidelines, datasets like HuskinDB have been created to report skin absorption endpoints. This review updates available skin permeability data by rigorously compiling research published between 2012 and 2021. Inclusion and exclusion criteria have been selected to build the most harmonized and reusable dataset possible. The Generative Topographic Mapping method was applied to the present dataset and compared to HuskinDB to monitor the progress in skin permeability research and locate chemotypes of particular concern. The open-source dataset (SkinPiX) includes steady-state flux, maximum flux, lag time and permeability coefficient results for the substances tested, as well as relevant information on experimental parameters that can impact the data. It can be used to extract subsets of data for comparisons and to build predictive models.

Ultrasound-mediated topical delivery of econazole nitrate with potential for treating Raynaud's phenomenon

The study aims to assess the ultrasound-assisted econazole nitrate (EN) permeation from topically applied formulations with potential for treating Raynaud's phenomenon. Optimization of ultrasound parameters such as the distance of the horn, application time and amplitude were performed. In vitro percutaneous absorption studies were performed using econazole formulations (F2_HPMC dispersion, F4_Lipoderm® Activemax™ Cream) across the ultrasound-treated porcine skin and were compared with the control group (skin samples without ultrasound). Histology and ATR-FTIR studies were performed on treated skin samples. A constant frequency (20 kHz) ultrasound application with 40% amplitude, 0.5 cm distance between ultrasound horn and the skin surface for 2 min was optimized. The permeation of EN was found to be higher from ultrasound-treated skin samples than the control group. Drug permeation from F2_HPMC dispersion was found to be higher as compared to the other formulations and the marketed EN cream. Histological evaluation confirmed that F2_HPMC dispersion showed no signs of toxicity. ATR-FTIR studies revealed a slight increase in the CH₂ stretching vibrations (~2920 cm^-1 and 2850 cm^-1) in ultrasound-treated skin samples as compared with the control. In conclusion, the ultrasound-assisted transdermal delivery of F2_HPMC dispersion could be further studied as a new therapy for Raynaud's phenomenon.

Alternatives to Biological Skin in Permeation Studies: Current Trends and Possibilities

: The transdermal route of drugs has received increased attention in recent years due to numerous advantages over the oral and injectable routes, such as avoidance of the hepatic metabolism, protection of drugs from the gastrointestinal tract, sustained drug delivery, and good patient compliance. The assessment of ex vivo permeation during the pharmaceutical development process helps in understanding the product quality and performance of a transdermal delivery system. Generally, excised human skin relevant to the application site or animal skin is recommended for ex vivo permeation studies. However, the limited availability of the human skin and ethical issues surrounding the use of animal skin rendered these models less attractive in the permeation study. In the last three decades, enormous efforts have been put into developing artificial membranes and 3D cultured human skin models as surrogates to the human skin. This manuscript provides an insight on the European Medicines Agency (EMA) guidelines for permeation studies and the parameters affected when using Franz diffusion cells in the permeation study. The need and possibilities for skin alternatives, such as artificially cultured human skin models, parallel artificial membrane permeability assays (PAMPA), and artificial membranes for penetration and permeation studies, are comprehensively discussed.

Transdermal Delivery of Antipsychotics: Rationale and Current Status

The aim of this article is to provide the rationale for the development of transdermal formulations of antipsychotics by highlighting their main advantages, starting with an overview of the antipsychotic formulations that are currently available on the market. Progress regarding transdermal antipsychotic formulations was investigated by performing a search of papers, patents and clinical trials published in the last 10 years. Available data on antipsychotic transdermal formulations are reported and discussed, focusing on the characteristics of the dosage forms and their ability to promote drug absorption. Despite the current availability of a large number of antipsychotics, only a few of these drugs (e.g. aripiprazole, asenapine, blonanserin, chlorpromazine, haloperidol, olanzapine, prochlorperazine, quetiapine, and risperidone) have been developed as transdermal delivery systems. Several papers and patents show that transdermal formulations, such as creams, films, gels, nanosystems, patches, solutions, and sprays, have been evaluated with the aim of expanding the clinical utility of antipsychotic drugs. In particular, the employment of different strategies, such as the use of nanoparticles/vesicles, or permeation enhancers as well as microneedles with iontophoresis, may improve the absorption of antipsychotic drugs through the skin. However, few clinical trials on transdermal delivery of antipsychotic drugs are available and only delivery systems containing asenapine and blonanserin have shown interesting clinical results in terms of pharmacokinetic data, efficacy, and tolerability. Recently, the transdermal patch formulation of blonanserin was approved in Japan for the treatment of schizophrenia.