%0 Thesis
%9 Doctoral
%A Luo, L
%B UCL School of Pharmacy
%D 2017
%F discovery:1547646
%I UCL (University College London)
%P 267
%T Mechanistic studies on skin permeation models
%U https://discovery.ucl.ac.uk/id/eprint/1547646/
%X The assessment of skin permeation is critically important in many fields  and a suitable and robust model that may be used to quantify and predict  percutaneous penetration is necessary. Currently available models include in  vitro models using human skin, animal skin, synthetic membranes and cell  culture models. Recently, the Skin Parallel Artificial Membrane Permeation  Assay (PAMPA) has been proposed as a simple but high throughput screening  system that may be suitable to study skin permeation.  In the present study, a lipophilic active, ibuprofen and a hydrophilic active,  caffeine were selected to conduct in vitro permeation studies in the  conventional Franz cell models using silicone membrane, porcine skin and  human skin, and the novel Skin PAMPA model. The overarching aim was to  determine the utility of Skin PAMPA for routine in vitro skin permeation testing  with reference to topical formulations.  The in vitro permeation studies conducted in Franz cell models using  silicone membrane and porcine skin showed that as a lipophilic active,  ibuprofen permeated rapidly though silicone membrane and porcine skin.  Compared with ibuprofen, caffeine went through the skin more slowly. In vitro  permeation studies in Franz cell models using human skin indicated that the  ibuprofen percentage permeation values for human skin were much lower than  corresponding values in porcine skin as expected.   Various in vitro permeation studies were conducted in the novel skin  PAMPA model for different ibuprofen and caffeine formulations. In general, the  Skin PAMPA model did discriminate between different formulation types and  different solvent systems compared with other models, with low variability in  the permeation data. The more permeable nature of the PAMPA, silicone  membrane and porcine tissue models to ibuprofen compared with human skin  was also demonstrated, while the permeation of caffeine, a hydrophilic  compound, in the PAMPA model was comparable to that in human skin.