Enhanced Skin Permeation of Estradiol by Dimethyl Sulfoxide Containing Transdermal Patches

Dimethyl sulfoxide is a well-known and widely used dermal penetration enhancer. Its incorporation in transdermal patches would be highly desirable; however, due to its volatility this is extremely challenging. Here, we report on the feasibility of a dimethyl sulfoxide (DMSO) containing transdermal system containing estradiol as a model compound. Transdermal patches were prepared from duro-tak® 387-2510 containing various DMSO concentrations at different drying temperatures. The resulting patches were analyzed for DMSO content, estradiol and DMSO release, estradiol and DMSO permeation through excised porcine skin, and recrystallization during stability testing. Drying conditions in the range of 35° to 40° allowed a complete polymer solvents removal while retaining significant amounts of DMSO (≤10 mg/patch). Estradiol skin permeation increased 4-fold (Jss = 4.12 µg/cm-2·h-1) compared to DMSO-negative control (Jss = 1.1 ± 0.2 µg/cm-2·h-1). As additional benefit, estradiol recrystallization was inhibited by DMSO at even lowest solvent concentrations. Storage stability was limited to 6 months at 25 °C with a surprising discrepancy between DMSO content (significantly lower) and flux (not significantly different). Although the technical feasibility range is relatively narrow, such DMSO-containing matrix-type patches are able to significantly enhance drug permeation through the skin while ameliorating the product stability against recrystallization.

[Massive acute hypotonic hyperhydration following arthroscopic synovectomy]

We report the case of a 4 year old boy who developed a massive water intoxication as a complication during knee arthroscopy. The sodium plasma concentration dropped to 100 mmol/l postoperatively. This complication may be triggered by prolonged surgery time, excessive intra-articular pressure, capsular tears and low body weight. To prevent massive incorporation of hypoosmolar fluid, the inflation of a tourniquet as well as the use of NaCl 0,9% as irrigation fluid seems to be of advantage. The guidelines for replacing sodium in hyponatremia are discussed according to literature. In general, hyponatremia should be corrected in the same amount of time as it took for it to develop.

Carbon-based quantitation of pyrethrins by supercritical-fluid chromatography

All six insecticide active ingredients in pyrethrum extract were quantified by supercritical fluid chromatography and carbon calibration. Allethrin is a suitable reference compound for carbon calibration and pyrethrins calibrations. Carbon quantification in SFC is also applied to pyrethroids (phenothrin, permethrin, cypermethrin, fenvalerate and deltamethrin) and alkanes. Halogen substitution on pyrethroids requires halogens on the reference calibration compound. The method was applied to commercial extracts.