TRANSDERMAL AND DERMATOLOGICAL FORMULATIONS FOR DELIVERY OF PHARMA- AND COSMECEUTICALS INTO HEALTHY AND DISEASED SKIN
Matrix type Transdermal Delivery systems (TDS) are comprised of the drug dissolved or dispersed in a pressure sensitive adhesive (PSA) matrix and are designed to provide a controlled delivery through the skin and into systemic circulation. In this research, we investigated the effect of different PSAs (acrylate, polyisobutylene, and silicone) on drug permeation, release and adhesive properties of TDSs formulated with a model drug (lidocaine) at its saturation point. Results showed the choice of PSA affected the drug release and permeation profile. The acrylate systems contained ten times higher drug amount than silicone systems, but the permeation flux was only two folds higher. Results also showed that the drug release does not linearly correlate to saturation, as the silicone TDS with the lowest amount of drug loading, showed the highest release percentage. Apart from passive delivery, iontophoresis has been proven to be an effective active technique using low-level currents for delivery of active molecules. Hence, we investigated whether a microcurrent-generating device can enhance the delivery of a cosmetic agent (niacinamide) using different types of current waveforms. Results indicated that DC and pulsatile DC waveforms effectively enhanced the in vitro permeation of niacinamide, suggesting the feasibility of iontophoretic delivery of actives. In another aim, we investigated three types of excised human skin tissues, including healthy, atopic dermatitis, and psoriasis, and evaluated the effect of health status on skin characteristics and in vitro permeation and skin retention of hydrocortisone, upon topical administration. Transepidermal water loss and electrical resistance values, as well as drug amount retained in psoriatic skin, showed a significant difference compared to healthy skin, indicating that barrier dysfunction and structural changes in afflicted skin can have a substantial effect on drug permeation profile into/across diseased skin. In the last aim, we evaluated an activated carbon-based drug disposal system for its efficiency in deactivating prescription psychoactive medications (alprazolam, temazepam, zolpidem, and ketamine). The deactivation system efficiently adsorbed and deactivated approximately 94% of the tested medications within 8 hours and over 99% by 28 days showing that it provides a simple, safe and an efficient method for disposal of unused medications.
Dasht Bozorg, Behnam