COMPARATIVE PHARMACOKINETICS OF RHUBARB ANTHRAQUINONES LOADED NANOEMULSION BY DIFFERENT PLASMA DRUG CONCENTRATION CALCULATION METHODS

Rhubarb is widely used to treat constipation, hyperlipidemia, and obesity in China and other Asian countries. Rhubarb free anthraquinones (RhA) are the major components of rhubarb, which are considered to be responsible for its therapeutic effect. In this paper, RhA was constructed into RhA loaded nanoemulsion to increase their solubility and bioavailability. The contents of RhA monomers (aloe-emodin, rhein, emodin, chrysophanol, and physcion) in rat plasma were determined by HPLC equipped with YMC-Pack-ODS-C18 column. The mobile phase was selected as methanol: 0.1% phosphoric acid (75 : 25, v/v) with isocratic elution. Fluorescence detection was employed with an excitation wavelength of 435 nm and an emission wavelength of 515 nm. The total plasma RhA concentrations were individually calculated by adding-up and integration methods. The pharmacokinetic parameters were obtained by statistical moment analysis. The values of concentration-related parameters obtained by the adding-up method were higher than those obtained by the integration method, while the values of time-related pharmacokinetic parameters are in an indistinctive range. The results provided factual evidence for the application of integrated pharmacokinetics with the integrated plasma drug concentration calculation method