Transdermal penetrants ethanol

Perfusion of skin with transdermal-penetration-enhancing agents such as ethanol, DMSO-ds and propylene glycol was studied by in vitro P NMR [39]. Epidermal strips from abdominal pig skin were placed in a 10 mm O.D. NMR tube modified for continuous perfusion with buffered salt solution and a serial spectra were recorded on a Broker AMX500 spectrometer. Signal intensities for phosphomono- and di-esters PME and PDE, phosphocreatine PCr, inorganic phosphate Pi and nucleotide triphosphorate, >3-NTP were followed in time. Additional spectra were recorded when the perfusion medium contained dexamethasone. The dexamethasone perfusion resulted in a dose-dependent decrease in PCr and NTP levels and had an effect on PME metabolism. 

Vesicle systems, described as ethosomes composed of phospholipid, ethanol, and water, have been shown to enhance the transdermal delivery of minoxidil and testosterone when compared to more traditional formulations (Fig. The quantities of drug penetrating... 

Transdermal delivery is a case in point. The skin, particularly the stratum corneum presents a formidable barrier to diffusion. Materials used to enhance its permeability have ranged from simple solvents such as ethanol or propylene glycol to aromatic chemicals such as terpenoids. Such penetration enhancers appear to work by disrupting the lipid domains in the stratum... 

Ethanol and aqueous ethanol solutions of various concentrations (see Sections 8 and 17) are widely used in pharmaceutical formulations and cosmetics see Table 1. Although ethanol is primarily used as a solvent, it is also employed in solutions as an antimicrobial preservative. Topical ethanol solutions are also used as penetration enhancers " and as disinfectants. Ethanol has also been used in transdermal preparations in combination with Labrasol as a 7)... 

An approach published in 2001 based on research out of the Klibanov laboratory at MIT is to use ethanol [5]. Ethanol, isopropanol, and other alcohols have long been used successfully as penetration enhancers for medical applications. Ethanol is one of the first molecules to have been used as a transdermal enhancer, because its effects are so easily and well characterized and its systemic and local toxicities are understood. It is currently contained in commercial delivery systems for estradiol [17] and other bioactive molecules. Ethanol and isopropanol have been used in a variety of studies based on their effects on drug transport. More applications can be found in the patent literature [18]. 

DSC may also be used to determine the properties of lipid delivery systems, to facilitate penetration into the skin. Ethosomes are composed of phospholipids, ethanol and water to facilitate transdermal delivery because ethanol is a well known penetration enhancer. DSC curves comparing ethosomes and liposomes without ethanol showed transitions at -15.2 °C and 6.3 °C, respectively. This suggests that the ethosomes could be in a more fluid state. Further investigation showed that the increased fluidity may be attributed to the particle size and the fact that the phospholipid is solubilized in the ethosomal system. Even small amounts of ethanol are capable of disrupting the lipid bilayers and increasing fluidity... 

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