Establishment of a quantitative method for GC analysis of polyoxyethylene (35) castor oil in microemulsion extracts / 中国中药杂志

With the continuous exploration of microemulsions as solvents for traditional Chinese medicine extraction, polyoxyethy-lene(35) castor oil(CrEL), a commonly used surfactant, is being utilized by researchers. However, the problem of detecting residues of this surfactant in microemulsion extracts has greatly hampered the further development of microemulsion solvents. Based on the chemical structures of the components in CrEL and the content determination method of castor oil in the 2020 edition of the Chinese Pharmacopoeia(Vol. Ⅳ), this study employed gas chromatography(GC) and single-factor experiments to optimize the preparation method of methyl ricinoleate from CrEL. The conversion coefficient between the two was validated, and the optimal sample preparation method was used to process microemulsion extracts of Zexie Decoction from three batches. The content of methyl ricinoleate generated was determined, and the content of CrEL in the microemulsion extracts of Zexie Decoction was calculated using the above conversion coefficient. The results showed that the optimal preparation method for CrEL was determined. Specifically, 10 mL of 1 mol·L~(-1) KOH-methanol solution was heated at 60 ℃ for 15 min in a water bath. Subsequently, 10 mL of boron trifluoride etherate-methanol(1∶3) solution was heated at 60 ℃ for 15 min in a water bath, followed by extraction with n-hexane twice. CrEL could stably produce 20.84% methyl ricinoleate. According to this conversion coefficient, the average mass concentration of CrEL in the three batches of Zexie Decoction microemulsion extracts was 11.94 mg·mL~(-1), which was not significantly different from the CrEL mass concentration of 11.57 mg·mL~(-1) during microemulsion formulation, indicating that the established content determination method of this study was highly accurate, sensitive, and repeatable. It can be used for subsequent research on microemulsion extracts of Zexie Decoction and provide a reference for quality control of other drug formulations containing CrEL.

Safety study and compositional analysis of polyoxyethylene 35 castor oil by UPCC-Q-TOF-MS / 药学学报

A UPCC-Q-TOF-MS method was established to analyze the components of polyoxyethylene 35 castor oil. The separation was performed at 50 ℃ on a Waters Acquity UPCC system by an Torus Diol column (3.0 mm × 100 mm, 1.7 μm) with gradient elution of CO2 and methanol - acetonitrile (50∶50); the flow rate was 1.0 mL·min-1, the back pressure was 2 000 psi, and methanol containing 2.5 mmol·L-1 ammonium formate was used as ionization reagent, whose flow rate was 0.2 mL·min-1. Positive ion electrospray ionization (ESI) mode and MSE technology were used. The qualitative analyses were carried out by using precise mass information of the parent and product ions and a PCA model was established by UPCC-Q-TOF-MS. L-02 cells and RBL-2H3 cells were used to study the cytotoxicity and histamine release of CrEL samples in vitro. A total of 13 kinds of CrEL components were obtained and their structures were identified by UPCC-Q-TOF-MS, with 255 compounds in total. The percentage content of 13 types of components was calculated by the normalization method. The content of polyoxyethylene glycerol tri-ricinoleate (PGTri-ricinoleate) in all samples was 0.36% - 2.80% and the main components were polyethylene glycol, polyethylene glycerol and polyoxyethylene glycerol mono-ricinoleate. All samples have different degrees of cytotoxicity and histamine release, which is negatively correlated with the content of PGTri-ricinoleate and positively correlated with the content of polyoxyethylene glycol fatty acid esters. The UPCC-Q-TOF-MS method is simple and rapid, has strong separation ability and high accuracy. It is suitable for the analysis of CrEL components. It is suggested that the fatty acid composition should be included in the monograph of CrEL for injection to increase the content of PGTri-ricinoleate and decrease the content of polyoxyethylene glycol fatty acid esters, so as to improve the product safety.