HPLC Method for the Dosage of Paclitaxel in Copaiba Oil: Development, Validation, Application to the Determination of the Solubility and Partition Coefficients

A highly sensitive, simple, rapid, innovative and economic method has been developed and validated for the quantification of paclitaxel in a complex plant matrix, copaiba oil, by HPLC method. Chromatographic separation was performed by Uptisphere Strategy C-18 column and the detection was performed at 228 nm. No interfering peaks from highly complex matrices were observed during the paclitaxel elution. Standard curves of paclitaxel containing 10 mg of copaiba resin oil were linear over the concentration range from 200 to 1700 ng mL with a determination coefficient of 0.999 and lower regression residues with a homoscedastic dispersion. The lower quantification and detection limits were 33.8 and 10.1 ng mL, respectively. The accuracy and precision determinations were less or equal to 0.60 and 2.03 %, respectively. The method developed was successfully applied to the evaluation of paclitaxel in copaiba resin and essential oils by solubility and partition coefficient studies. Paclitaxel showed a lipophilic characteristic (log P > 1) and a higher solubility in copaiba oils. In conclusion, the method showed sensitivity, linearity, precision, accuracy, necessary specificity and robustness for a reliable separation, identification and quantification of paclitaxel in complex plant matrix. This new analytical method can be, therefore, also applied to quantify paclitaxel in drug delivery systems in which copaiba resin or essential oils are associated, such as lipid and polymer systems.