Docosanol is the only US Food and Drug Administration(FDA)approved over-the-counter topical product for treating recurrent oral-facial herpes simplex labialis.Validated analytical methods for docosanol are required to demonstrate the bioequivalence of docosanol topical products.A gas chromatography/selected ion monitoring mode mass spectrometry(GC/SIM-MS)method was developed and validated for docosanol determination in biological samples.Docosanol and isopropyl palmitate(internal standard)were separated on a high-polarity GC capillary column with(88％cyanopropy)aryl-polysiloxane employed as the stationary phase.The ions of m/z 83 and 256 were selected to monitor docosanol and isopropyl palmitate,respectively;the total run time was 20 min.The GC/SIM-MS method was validated in accordance with US FDA guidelines,and the results met the US FDA acceptance criteria.The docosanol calibration standards were linear in the 100-10000 ng/mL concentration range(R2＞0.994).The recoveries for docosanol from the receptor fluid and skin homogenates were＞93.2％and＞95.8％,respectively.The validated method was successfully applied to analyze ex vivo human cadaver skin permeation samples.On applying Abreva?cream tube and Abreva?cream pump,the amount of doco-sanol that penetrated human cadaver skin at 48 h was 21.5±7.01 and 24.0±6.95 ng/mg,respectively.Accordingly,we concluded that the validated GC/SIM-MS was sensitive,specific,and suitable for quantifying docosanol as a quality control tool.This method can be used for routine analysis as a cost-effective alternative to other techniques.

AIM: To study the chemical constituents and their bioactivity of Polygonum amplexicaule. METHODS: The isolation of compounds was achieved by chromatographic techniques and structure of the isolates was established by UV, IR, HRESI-MS and NMR including 1D and 2D experiments. RESULTS: Bioassay-guided fractionation of an ethanolic extract of Polygonum amplexicaule led to the isolation of a hitherto unidentified compound, 5, 6-dihydropyranobenzopyrone (1) along with nine previously known compounds (2-10). Compounds 2-10 were identified as amplexicine (2), catechin (3), rutin (4), quercetin-3-O-β-D-galactopyranoside (5), chlorogenic acid (6), galloyl glucose (7), caffeic acid (8), gallic acid (9) and scopletin (10). CONCLUSION Compound 1 is new. Compounds 1-10 exhibited considerable antioxidant activity in a 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay.
Antioxidants ; chemistry ; isolation & purification ; pharmacology ; Biphenyl Compounds ; metabolism ; Coumarins ; chemistry ; isolation & purification ; pharmacology ; Molecular Structure ; Picrates ; metabolism ; Plant Extracts ; chemistry ; pharmacology ; Polygonum ; chemistry