Development of Procaine Loaded Transdermal Patches Based on Biopolymer Pectin, Castor Oil, and Polyethylene Glycol for Controllable Drug Release Studies and Their Characterizations

Transdermal drug delivery systems have considerable attention in clinical and point-of-care applications due to their superior advantages such as non-invasive properties and keeping drug efficiency. To overcome the skin barrier, penetration enhancers are employed in the patch design. Chemical penetration enhancers are the most frequently applied way to improve drug diffusion through the barrier. Transdermal patches are designed as a drug-loaded thin-film hydrogel. Since the patch material must be biocompatible and eco-friendly, in this study, pectin-based transdermal patches are designed, and procaine, a painkiller drug is chosen as a model drug. Benzyl alcohol, polyethylene glycol, and castor oil are selected as chemical penetration enhancers. Drug diffusion experiments are carried out by using Franz diffusion cells at 37 °C. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) are used to characterize the chemical structure and thermal properties of the patches. The patches are evaluated by the contact angle measurement and the swelling test in terms of their hydrophilicity and water uptake. Regarding in vitro drug release experiments by Franz diffusion cells, drug-loaded patches were examined (CxPy-PC; C-castor oil, P-PEG, x-y amounts (mg)). It is found that the most promising results come from C10-P5-PC (12.7 mg drug/g film) and C30-P5-PC (11.4 mg drug/ g film) which can be attributed to the synergetic and optimum amount of polyethylene glycol and castor oil.