Minoxidil, a pyrimidine derivative (2, 4-diamino-6-piperidinopyrimidine-3-oxide) is the only topical medical treatment with proven efficacy for the treatment of androgenic alopecia that showed low skin penetration and bioavailability. The main aim of this research was to investigate the effect of some permeation enhancers on the in vitro skin permeability of minoxidil. Minoxidil permeability experiments through rat skin pretreated with some of permeation enhancers namely, Urea, Eucalyptus oil and Menthol were performed in fabricated Franz diffusion cells and compared with hydrated rat skin as control. The permeability parameters evaluated include steady-state flux (Jss), permeability coefficient (Kp), and diffusion coefficient (D). The penetration enhancer’ s permeability enhancement mechanisms were investigated by comparing of changes in peak position and their intensities of asymmetric (Asy) and symmetric (Sym) C-H stretching, C=O stretching, C=O stretching (Amide I) and C-N stretching of keratin (Amide II) absorbance using Fourier transform infrared spectroscopy (FTIR), as well as by comparing mean transition temperature (Tm) and their enthalpies (Δ H) using differential scanning calorimetry (DSC). Minoxidil permeability parameters through rat skin, were evaluated with and without chemical enhancers such as Eucalyptus oil, menthol, and urea. The skin showed barrier for minoxidil permeability through whole skin and that diffusion into the skin was the rate-limiting step for drug flux. Urea, Eucalyptus oil, and Menthol were the most effective enhancers as they increased flux 1. 86, 2. 16, and 1. 75 times and diffusion coefficient 3. 25, 1. 34 and 2. 16 folds in comparison with hydrated skin, respectively. FTIR and DSC results showed lipid fluidization, extraction, disruption of lipid structure and irreversible denaturation of proteins in the SC layer of skin by permeation enhancers.

Nicotine transdermal systems are being used as an aid to smoking cessation programs. As the kinetics of nicotine delivery is important in success of a smoking cessation program, rapid and high input of nicotine is required, which is not possible by passive methods and requires enhancement strategies such as iontophoresis. Iontophoretic permeation, of nicotine looks promising, based on published data on human skin. However, to optimize this method, permeation pathways should be known and further parameters have to studied, which are the subject of the present investigation. In this study iontophoretic permeation of nicotine through rat skin was performed and the effects of different variables on this phenomenon were studied. Anodic iontophoresis of nicotine from a solution at pH 2.8, using a 0.5 mA/cm2 current density resulted in a considerable enhancement (about 3-fold) of nicotine absorption through rat skin. Nicotine concentration and current density showed a directly increasing effect on permeation of the drug, but the effect of concentration was not linear. Pulsatile current delivery was more effective in permeation of nicotine than the continuous method. Anodic iontophoresis was around 2-fold more effective than the cathodic method in increasing the flux. Post iontophoretic permeation studies showed good reversibility of the membrane barrier properties. Results were in good agreement with the reported human data and might be considered as an evidence of the ability of rat skin to model human skin and also the importance of intercellular pathway of the stratum corneum in iontophoretic delivery of nicotine and possibly other drugs. Donor's pH showed no effect on permeation of nicotine under the studied conditions, pH values of <3. Results also showed that the electr-osmotic flow could occur at pH values lower than 4. Finally, this study show that by controlling the effective parameters of iontophoretic delivery, a more effective nicotine transdermal delivery method would achievable.

Using of nanocomposite membranes composed of polymer and inorganic nanoparticles is a novel method to enhance gas separation performance. In this study, membranes were fabricated from polyester (PE) containing silica (SiO2) nanoparticles and gas permeation properties of the resulting membranes were investigated. Morphology of the membranes, SiO2 distribution and aggregates were observed by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis. Furthermore, thermal stability, the residual solvent in the membrane film, and structural ruination of membranes were analyzed by ThermoGravimetric Analysis (TGA). The effects of SiO2 nanoparticles on the glass transition temperature (Tg) of the prepared nanocomposites were studied by Differential Scanning Calorimetry (DSC). The results obtained from gas permeation experiments with a constant pressure setup showed that adding SiO2 nanoparticles to the polymeric membrane structure increased the permeability of the membranes.

Background: Nanostructured lipid carriers (NLCs) are emerging as the second generation of lipid nanoparticles to solve the shortcomings of the first generation (structured lipid carriers). Terbinafine hydrochloride is used to treat various fungal skin diseases.   Objectives: The study’s main objective was to study the drug release and permeation between NLC and NLC-based gel formulation to select the better one.   Methods: A central composite face-cantered (α=1) design with two components (the amount of liquid lipid and the homogenization speed) and 13 runs were used through Design-Expert® software (version 7. 1. 5). Terbinafine hydrochloride-loaded NLC (TH_NLC) was produced by using the hot-homogenization technique. Fourier transform infrared study was done to determine drug excipients’ compatibility. Dynamic light scattering (DLS) was employed to determine particle size. Utilizing scanning electron microscopy (SEM), the morphology and shape of the TH_NLC formulation were examined. The hydrogel was filled with the optimized products chosen by point prediction in design expert software. These products were assessed by their pH, spreadability, viscosity, homogeneity, extrudability, and drug content. The in vitro drug release study and the ex vivo permeation investigation for the optimized TH_NLCopt and TH_NLCopt gel formulation were carried out using Franz diffusion cells Results: The formulation contains nanoscale particles, as evidenced by the size range of the particles (17. 57 to 329. 4 nm). Entrapment efficiency was 60. 95% and 98% for TH_NLCopt TH_NLCopt gel, respectively. Within 7 hours, 96. 35% and 83. 37% of the drug were released from optimized NLC and NLC-based gel, respectively. The amount of drug that had penetrated the skin in 7 hours ranged from 54. 19% to 31. 16%, with a retention range of 22. 46% to 61. 87%.   Conclusion: The topical delivery of the TH_NLC-based gel system is quite promising.

Transdermal drug delivery (TDD) is a non-invasive, topical administration method for therapeutic agents. Transdermal delivery also has advantages including providing release for long periods of time, improving patient compliance, and generally being inexpensive. Despite these advantages, the use of TDD has been limited by innate barrier functions of the skin. Only small (<500 Da), lipophilic molecules can passively diffuse through the skin. As a result of the barrier function of the skin, passive transdermal delivery has primarily been limited to small molecules. The skin, which consists of several layers including the stratum corneum, other epidermal layers, and dermis, is the primary defense system of the body. The main barrier to therapeutic delivery is the outermost layer of the skin, the stratum corneum. As a result, various methods of skin permeabilization have been explored for their ability to enhance the transport of drugs across the stratum corneum. Scientists evaluated new drug delivery systems such as nano-carriers and drug delivery systems and enhancer methods such as penetration enhancers.The purpose of drug delivery systems are to deliver sufficient drug molecules into the skin with maximum stability and minimal toxicity. To guarantee successful transdermal drug delivery, a drug delivery system must exhibit several essential properties including drug protection, targeted drug delivery, biocompatibility and biodegradability.This paper reviews transdermal drug delivery systems, recent enhancement techniques to optimize drug delivery such as microneedles and especially vesicular systems. Herein, we focus on the differences in their composition, physicochemical properties and applications of those drug delivery systems. We hope recent innovations can work as a foundation for further research and development in transdermal drug delivery system.

N, N-Diethyl meta Toluamide (DEET) is an insect repellent agent that contrary to its benefits, if is used in formulations with high skin permeation, will produce side effects of different severity. This study attempted to achieve a semi-solid DEET containing formulation with good appearance, sufficient spreadity, suitable viscosity for tube and jar filling, compatible pH with skin, reasonable stability, longer release time, and the less skin permeation. To obtain such a formulation, three types of DEET containing semi solids including gels (hydrophile), creams (emulsion) and ointments (lipophile), and their characteristics were compared with each other and with Off! Brand. Results showed that one of the prepared creams with the proper viscosity, stability, appearance and spreadity, had the least drug release in six hours and less skin permeation of DEET as compared with Off!. Hence the preparation was introduced as the optimal formulation.

Purpose: Due to limited oral bioavailability of doxorubicin (Dox) many efforts during the last decades focused on the development of novel delivery systems to overcome these limitations. In the present study, Dox encapsulated chitosan nanoparticles were prepared to evaluate the intestinal permeation of Dox via oral administration. Methods: Nanoparticles were fabricated based on ionic gelation method using tripolyphosphate. Some physicochemical properties, such as nanoparticle size and morphology, loading efficiency and in vitro drug release in 3 different pH values (5. 0, 6. 8 & 7. 4) were evaluated. Intestinal permeations of free Dox and Dox loaded in nanoparticles were assessed using rat intestinal sac model. Results: The nanoparticles were spherical shape with average size of 150 ± 10 nm. The entrapment and loading efficiency of Dox were up to 40% and 23%, respectively. According to the release profiles, up to 30% of loaded drug was released within 6hrs and the remaining amount of Dox was released more gradually, but this pattern was related to pH of the medium. The amount of drug released at acidic condition (pH 5. 0) was greater than other pHs. The intestinal permeation of Dox increased nearly up to 90% by loading in chitosan nanoparticles. Conclusion: Using chitosan nanoparticles presents a potential safe drug delivery system for oral administration of Dox. In vivo studies and the determined pharmacokinetic and pharmacodynamic of Dox loaded chitosan nanoparticles after oral administration are planned for future studies.