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The impact of consuming curcuminoids containing curcumin at 500 mg/day and 6 g/day for 7 days on plasma antioxidant capacity and serum cholesterol level were determined by using vitamin E 200 IU/day consumption as a comparison. Group A and group B subjects consumed 500 mg and 6 g curcumin, respectively, but group C subjects consumed vitamin E 200 IU. By using the oxygen radical absorbance capacity (ORAC) assay, it was found that plasma antioxidant capacity of group A rose from a baseline of 13% to 24% on day 1 and day 7, as against a 19-20% increase for group B. Serum cholesterol and triglyceride levels were significantly decreased after curcumin treatment at 500 mg/day. By consuming vitamin E, both ORAC values and plasma α-tocopherol concentrations were significantly increased, but only very slight responses on serum cholesterol or triglyceride levels were observed. It is therefore suggested that curcumin supplement would not be appropriate for healthy people except for reducing serum cholesterol or triglyceride levels. The dosage of a daily curcumin supplement at 500 mg is more effective than 6 g, although vitamin E is also considered to be an effective antioxidant supplement.

The purpose of this study was to investigate the effects of vehicles, enhancers, and polymer membranes on 3'-azido-3'-deoxythymidine (AZT) permeation across cadaver pig skin. Four binary vehicles (ethanol/water, isopropyl alcohol/water, polyethylene glycol 400/water, and ethanol/isopropyl myristate [IPM]) were tested for AZT solubility and permeability across pig skin; ethanol/IPM (50/50, vol/vol) demonstrated the highest AZT flux (185.23 microg/cm2/h). Next, the addition of various concentrations of different enhancers (N-methyl-2-pyrrolidone [NMP], oleic acid, and lauric acid) to different volume ratios of ethanol/IPM was investigated for their effect on AZT solubility and permeability across pig skin. The use of 2 combinations (ethanol/IPM [20/80] plus 10% NMP and ethanol/IPM [30/70] plus 10% NMP) resulted in increased AZT solubility (42.6 and 56.27 mg/mL, respectively) and also high AZT flux values (284.92 and 460.34 microg/cm2/h, respectively) without appreciable changes in lag times (6.25 and 7.49 hours, respectively) when compared with formulations using only ethanol/IPM at 20/80 and 30/70 volume ratios without addition of the enhancer NMP. Finally, AZT permeation across pig skin covered with a microporous polyethylene (PE) membrane was investigated. The addition of the PE membrane to the pig skin reduced AZT flux values to 50% of that seen with pig skin alone. However, the AZT flux value attained with ethanol/IPM (30/70) plus 10% NMP was 215.31 microg/cm2/h, which was greater than the target flux (208 mug/cm2/h) needed to maintain the steady-state plasma concentration in humans. The results obtained from this study will be helpful in the development of an AZT transdermal drug delivery system.

No abstract

A simple and rapid reversed-phase high-performance liquid chromatographic method was developed and validated for the determination of endogenous alpha-tocopherol in human plasma. Following addition of alpha-tocopheryl acetate as the internal standard, the plasma was deproteinized using acetonitrile and isopropanol mixture prior to HPLC analysis. Methanol was used as the mobile phase and the effluent was quantitated at 292 nm. By this developed method, the concentrations of alpha-tocopherol were linearly related to their responses in the range of 0.8-30 microg/mL. The relative standard deviations intra-day and inter-day for alpha-tocopherol in plasma were less than 10%. The percentage of bias was within +/-4%, which confirmed the accuracy of the method. The method has been successfully applied for determining endogenous alpha-tocopherol in healthy Thai male volunteers.