Background Skin being the largest organ of the human body plays a very important role in the permeation and penetration of the drug. In addition, the transdermal drug delivery system (TDDS) plays a major role in managing dermal infections and attaining sustained plasma drug concentration. Thus, evaluation of percutaneous penetration of the drug through the skin is important in developing TDDS for human use. Material and methods Various techniques are used for getting the desired drug penetration, permeation, and absorption through the skin in managing these dermal disorders. The development of novel pharmaceutical dosage forms for dermal use is much explored in the current era. However, it is very important to evaluate these methods to determine the bioequivalence and risk of these topically applied drugs, which ultimately penetrate and are absorbed through the skin. Results Currently, numerous skin permeation models are being developed and persuasively used in studying dermatopharmacokinetic (DPK) profile and various models have been developed, to evaluate the TDD which include ex vivo human skin, ex vivo animal skin, and artificial or reconstructed skin models. Conclusion This review discusses the general physiology of the skin, the physiochemical characteristics affecting particle penetration, understand the models used for human skin permeation studies and understanding their advantages, and disadvantages.

Various dressings are available to heal chronic wounds which many times fail to achieve the expected results. To overcome some of their drawbacks, formulation of a novel dressing; lyophilized liposomal wafers having better wound healing potential has been proposed in the present study. The drug incorporated in the formulation is gatifloxacin (GTX) which is a fourth-generation fluoroquinolone antibiotic having in vitro activity against both Gram-negative and Gram-positive bacteria. The formulation was designed in three stages where at first liposomes were prepared, the liposomes were converted to gel using chitosan and lastly this gel was lyophilized to form liposomal wafers. Liposomes were prepared by varying the concentration of lipid and cholesterol and evaluated for particle size, entrapment efficiency, in vitro cumulative release, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Liposomes were converted to liposomal gel using chitosan and evaluated for texture, clarity, viscosity, spreadibility and in vitro drug release. Finally, this liposomal batch was subjected to lyophilization to convert it to liposomal wafers and subjected to SEM, differential scanning calorimetric, X-ray diffraction and drug release studies. The in vivo studies were carried out on Wistar rats where wound healing potential of the wafers was confirmed by histopathological evaluation.