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A reversed-phase high-performance liquid chromatographic method is described for the simultaneous determination of four anthraquinones: rhein, aloe-emodin, emodin, and chrysophanol in Senna alata leaves. The method involves the use of a TSK-gel ODS-80Tm column (5 microm, 4.6 x 150 mm) at 25 degrees C with the mixture of methanol and 2% aqueous acetic acid (70:30, v/v) as the mobile phase and detection at 254 nm. The parameters of linearity, precision, accuracy, and specificity of the method were evaluated. The recovery of the method is 100.3-100.5%, and linearity (r(2) > 0.9998) was obtained for all anthraquinones. A high degree of specificity as well as repeatability and reproducibility (relative standard deviation values less than 5%) were also achieved. The solvent for extraction of anthraquinones from S. alata leaves was examined in order to increase the anthraquinone content of the leaf extract. It was found that a solution of 5% hydrochloric acid (v/v), 5% ferric chloride (w/v), and 15% water in methanol (v/v) was capable of increasing the anthraquinone content in the leaf extract up to 1.67% (w/w).

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Natural rubber latex is a colloidal dispersion of polymer particles in a liquid. It is harvested from rubber trees by a tapping process. Synthetic rubber is one type of artificial elastomer mainly synthesized from petroleum byproducts. It has good mechanical property, thermal stability, and compatibility with petroleum products. It can undergo much more elastic deformation under stress than most materials, and can return to its original size without changing permanently. Commonly, many drugs taken via the oral route are ineffective because of the first pass metabolism and drug degradation in the gastrointestinal tract. Thus, transdermal drug delivery systems can improve the disadvantage of orally taken drugs. There must be significant controlled drug release into the systemic blood circulation to target organs via the skin. In this review article, the use of rubber polymers in both natural and synthetic rubber types as a material for transdermal drug delivery systems will be reported.

The TLC-densitometric and TLC-image analysis methods provided a similar reproducibility, accuracy and selectivity for the quantitative determination of γ-oryzanol in cold pressed rice bran oil. A statistical comparison of the quantitative determinations of γ-oryzanol in samples did not show any statistically significant difference between TLC-densitometric and TLC-image analysis methods. As both methods were found to be equal, they therefore can be used for the determination of γ-oryzanol in cold pressed rice bran oil.

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