Transdermal Evaporation Drug Delivery System: Concept to Commercial Products

Abstract

Since two decades or so transdermal route established itself as better alternative to traditional oral route. This is possible due to continuous innovations in transdermal drug delivery (TDD), which not only enables researchers from academia and industry to successfully develop and launch many new pharmaceuticals but also allow to include new classes of drugs that can be developed into transdermal formulations. These successes are achieved due to the use of novel techniques based on either physical or chemical approaches. However, both of these techniques suffer due to their own disadvantages. Comparatively, a simple method of supersaturation to enhance drug permeation across skin has created a new wave of interest. Even though the application supersaturated principle in topical and TDD has been used from 1960s, but proper control of drug release and formation of stable supersaturated states has been the core of intense research in the last decade. Out of various methods used to get supersaturated system, evaporation method is considered as most efficient and practically feasible for TDD. Therefore, in this review concept of supersaturation, selection of solvent system and the mechanism of inhibition of crystallization are discussed. Application of evaporation systems in the development of transdermal formulations such as solutions, semisolids and metered dose therapeutic systems (MDTS) and the commercial evaporative systems are also discussed in this review.

A Novel Binary Supercooled Liquid Formulation for Transdermal Drug Delivery

“…Transdermal drug delivery system (TDDS) is one of the most exciting parenteral drug delivery systems in the pharmaceutical field. 1) TDDS confers several advantages such as decreasing dosing frequency, reducing side effects, and avoiding hepatic first-pass metabolism. 2,3) Despite these advantages, TDDS often has difficulty in drug permeation ability because the skin's hydrophobic stratum corneum acts as an effective barrier.…”

Development of Topical/Transdermal Self-Emulsifying Drug Delivery Systems, Not as Simple as Expected

“…Therefore, lower drug concentrations incorporated into topical/transdermal SEDDSs might not be problematic [28,33]. On the other hand, supersaturated vehicles destined for topical/transdermal drug delivery have high success rates due to enhanced flux values as the high drug concentration of the vehicle establishes a driving force for drug partitioning into the skin due to maintained saturated drug concentrations at the skin surface [33,53]. Remarkably, supersaturated SEDDSs evidently rendered the inhibition of drug precipitation in a kinetic and thermodynamic fashion by slowing crystal growth together with nucleation [33].…”

“…Remarkably, supersaturated SEDDSs evidently rendered the inhibition of drug precipitation in a kinetic and thermodynamic fashion by slowing crystal growth together with nucleation [33]. Therefore, it might be more advantageous to present supersaturated SEDDSs at the skin surface compared to decreased drug concentrations [53].…”

“…In order to achieve enhanced oral drug delivery, a rapid emulsification of the SEDDSs is desired, since spontaneous emulsification marks the rate-limiting step before drug absorption can occur [124]. Contrarily, the rate-limiting step for the majority of drugs intended for topical/transdermal delivery is identified as diffusion through the lipophilic shield established by the SC [53,56]. The differences between the diffusion of SEDDSs destined for topical/transdermal drug delivery and the absorption of orally administered SEDDSs are displayed in Figures 4 and 5 It is a priority during topical/transdermal drug delivery to increase the contact time between the skin surface and applied formulation in order to improve dermal drug diffusion [21,125].…”

Enhancement of skin permeability with thermal ablation techniques: concept to commercial products

“…It was reported that penetration enhancers, particularly organic solvents and surfactants, induce different skin ailments such as contact urticaria, erythema, and burning sensation [17]. In addition, there is no report in the literature on the long-term effect of penetration enhancers on the skin and particularly on the SC [18]. Active methods use the application of external energy as driving force or by physically disrupting the SC for enhancing drug transport through skin.…”