Characterization of Natural Rubber Latex Film Containing Various Enhancers

Natural rubber latex (NRL) is often used to prepare the blended films by solution-casting technique. Its film presents interesting physical properties in elasticity and adhesiveness. From the good physical properties of NRL, it can beused to prepare transdermal patches which gain popularity due to several advantages such as convenient application, avoid first-pass metabolism, possibly to attain sustained and constant drug levels. However, the skin serves an excellent barrier against drug permeation due to the rigid lamellar structure of the stratum corneum lipids. Enhancers can improve the partition of drug into the stratum corneum by increasing the thermodynamic activity of the drug in transdermal formulations. The aims of this study were (i) to prepare the blended films from deproteinized NRL (DNRL), hydroxypropylmethyl cellulose (HPMC), dibutyl phthalate (DBP), various enhancers, i.e., fatty acid (oleic acid), ester of fatty acid (isopropyl palmitate; IPP), fatty alcohol (propylene glycol; PG), hydrocarbon (olive oil), and terpene (menthol), and (ii) to study the physical and mechanical properties of the obtained films. The results showed that DNRL could be compatible with all enhancers. Hence, the blended films were characterized for strength (ultimate tensile strength; UTS), elasticity (elongation at break), and adhesiveness (peel strength and tack adhesive). It was found that these characteristics depended on type and concentration of incorporated enhancers.