Determination of trehalose by ion chromatography and its application to a pharmacokinetic study in rats after intramuscular injection

Simultaneous determination of chito-oligosaccharides in rat plasma by the LC-MS/MS method: application to a pharmacokinetic study

A simple and sensitive method for the simultaneous determination of chito-oligosaccharides (COSs) with degrees of polymerization (DPs) from 2 to 7 was developed and used for COS quantification in rat plasma. Samples were separated on a Waters XBridge Amide column (3.5 μm, 2.1 × 150 mm) by isometric elution with 10 mM aqueous ammonium acetate (pH = 9) in acetonitrile and 10 mM aqueous ammonium acetate (pH = 9) (v/v, 50 : 50) employing multiple reaction monitoring (MRM) detection. Analytes and internal standards (IS) were extracted from rat plasma by protein precipitation with acetonitrile. The assay was linear over a concentration range of 20-10 000 ng mL-1 for COS2-7. The intra-day and inter-day precision of the investigated components exhibited an RSD within 15%, and the accuracy (RE%) ranged from -7.3% to 7.6%. The extraction recoveries of the six constituents were determined to be between 82.5% and 94.3%. No significant matrix effects for COS2-7 were observed in rat plasma. COS in plasma remained stable for 24 h at room temperature (short-term), after freeze-thaw cycles, and 30 days in a -40 °C freezer. In comparison to reported COS quantitation methods, this method is simple, sensitive and cost-effective and could be used for the simultaneous quantitation of COS2-7. This method meets the Food and Drug Administration guidelines and had been successfully applied to the analysis of pharmacokinetic samples collected from rats.

UPLC-MS/MS Method for the Simultaneous Quantification of Eight Compounds in Rat Plasma and Its Application to a Pharmacokinetic Study after Oral Administration of Veratrum (Veratrum nigrum L.) Extract

Veratrum nigrum L. is a well-known traditional Chinese medicine with a lot of pharmacological activities including antihypertensive, anticancer, and antifungal effects. In the current experiment, a rapid and sensitive UPLC-MS/MS method that takes only 7 min run time has been established and validated for simultaneous determination of eight bioactive compounds including cyclopamine, jervine, veratramine, polydatin, quercetin, apigenin, resveratrol, and veratrosine in rat plasma. The chromatographic separation of analytes and internal standard was performed on a Phenyl-Hexyl column (2.1 × 100 mm, 1.7 μm) with the mobile phase consisting of water (0.1% formic acid) and acetonitrile at a flow rate of 0.3 mL/min. An electrospray ionization (ESI) source was used to detect the samples in both positive and negative ion modes. The intra- and interday precisions of the compounds were less than 9.5% and the accuracy ranged from -10.8% to 10.4%. The extraction recoveries of the compounds were in the range of 85.1 ± 1.5% to 102.6 ± 8.0%, and the matrix effect ranged from 91.2 ± 4.5% to 113.8 ± 1.5%. According to the results of the stability test, the eight compounds have good stability under various conditions and the relative standard deviation (RSD) less than 13.2%. The pharmacokinetic parameters of the eight compounds in rat plasma after oral administration of Veratrum nigrum L. extract were successfully determined by the established UPLC-MS/MS method.

Exploring Trehalose on the Release of Levonorgestrel from Implantable PLGA Microneedles

Hydrophobic drugs wrapped in poly (lactic-co-glycolic acid) (PLGA)-based microneedles (MNs) require a long time to release completely. To obtain the desired duration, it is still necessary to modulate the release of hydrophobic drugs from MNs, while the PLGA composition is unchangeable. In this work, implantable PLGA microneedles (IPMNs) composed of PLGA arrowheads encapsulating levonorgestrel (LNG) and a water-soluble supporting array were designed. We explored trehalose used as a porogen on the release of hydrophobic LNG from PLGA-based MNs. Varying the trehalose content in PLGA arrowheads could induce different rates of drug release. The highest cumulative release of LNG was 76.2 ± 3.9% for IPMNs with 33.3% trehalose during 21 days in vitro, while the cumulative release of LNG was 60.4 ± 3.5% for IPMNs without trehalose. Pharmacokinetic results in rats showed that plasma levels of LNG were sustained for 13 days for IPMNs with 33.3% trehalose and 16 days for IPMNs without trehalose. Furthermore, the PLGA arrowheads with trehalose degraded more rapidly than those without trehalose over 21 days in rats. Consequently, using trehalose as a porogen was a feasible approach to modulate the release of a hydrophobic drug from PLGA-based MNs.