Permeation of Pharmaceutical Compounds Through Silanized Poly(dimethylsiloxane)

Abstract

This work evaluates permeation of twelve model pharmaceutical compounds through a chemically modified form of poly(dimethylsiloxane) (PDMS), whereby the polymer surface had undergone silanisation. Standard polymer membrane has been widely used as a simplified skin model to investigate transdermal permeation yet does not fully mimic human skin. The surface chemistry of modified polymer was investigated such as the ability to bind to drugs, hydrophobicity and pore size using optical microscopy, the Brunauer-Emmett-Teller (BET) technique and Fourier-transform Infrared Spectroscopy (FTIR), followed by permeation analysis with UV spectroscopy. For eleven of the twelve compounds an appreciable increase in the extent of permeation was observed after six hours when using the silanised polymer compared with the standard PDMS. Furthermore, a correlation was found between the degree of permeation increase and hydrophobicity (logP) of the drug (R 2 = 0.90). These findings indicate that permeation can be controlled by modifying the membrane surface, although the hydrophobicity of the permeant also plays a vital role in the extent of permeation observed. This concept study presents a potential alternative membrane for pharmaceutical transdermal analysis, providing many benefits over existing options.

Poly(dimethylsiloxane): A Sustainable Human Skin Alternative for Transdermal Drug Delivery Prediction

“…Another interesting aspect of this particular polymer membrane is the well-developed silicon chemistry it exhibits, enabling one to replace the methyl group by a wide range of functional groups 31,57,[82][83][84] . It is also reported that tailored properties can be achieved by the judicious choice of the chemical substitute, including skin-like properties.…”

“…Such studies highlight the possibility of tailoring the membrane to most successfully replicate human skin data, alongside factors such as donor compartment composition 91 . Other possibilities include chemical modification of the PDMS surface, such as a recent publication confirmed the extent and profile of drug permeation can be immensely altered by silanising the surface of PDMS 84 . In this case it was found that there was an appreciable increase observed in the extent of permeation compared with standard PDMS, i.e.…”