Pharmacokinetics of HupA-PLGA-NPs of different sizes in the mouse blood and brain determined by LC-MS/MS.

OBJECTIVE: Huperzine A, which was extracted from a Chinese herb, is a reversible and selective inhibitor of acetylcholinesterase (AChE), which is used as an anti-Alzheimer's drug that exerts evident pretreatment effects against exposure to organophosphate chemical warfare agents or pesticides. The aims of this study were to establish an LC-MS/MS method for the detection of HupA in biological samples and to investigate the pharmacokinetics of HupA polylactic-co-glycolic acid nanoparticles (HupA-PLGA-NPs) with different diameters in mice. MATERIALS AND METHODS: The proposed LC-MS/MS method was established by optimizing the MS conditions and validating the specificity, linear range, lower limit, precision, accuracy, matrix effects, absolute recovery, and sample stability of the method. ICR mice were divided into three treatment groups: the HupA control group, the 46.4-nm HupA-PLGA-NP group and the 208.5-nm HupA-PLGA-NP group. All the mice in the three groups were administered 0.5 mg/kg HupA via the tail vein. The pharmacokinetic parameters in plasma and the brain were detected by LC-MS/MS. Pharmacokinetic parameters were analyzed using PKS pharmacokinetic software, and the relative bioavailability and brain-targeted drug targeting efficiency (DTE) were also calculated. RESULTS: The distributions of HupA-PLGA-NP groups showed marked changes compared with that of HupA in mice in vivo, and the particle size of nanodrugs exerted a significant effect on the pharmacokinetic parameters in mice. The halflife (T1/2) values in plasma of the 46.4- and 208.5-nm HupA-PLGA-NPs were 1.53- and 1.96-fold longer than that of the HupA at the same dose. The bioavailabilities of the two nanoparticles were 1.93- and 2.19-fold higher than that of HupA, respectively. In the brain, the Tmax values of the two HupA-PLGA-NPs of different sizes was 1.25 h, which was clearly longer than that of HupA (0.5 h), and the corresponding T1/2 values were 12.53 h and 8.47 h, which were 1.82- and 1.23-fold higher than that of HupA (6.89 h). In addition, the brain targeting index of the 46.40-nm HupA-PLGA-NPs was 1.48, which revealed an evident brain-targeting effect. CONCLUSIONS: The LC-MS/MS method has the advantages of good specificity, high sensitivity and needing a low sample amount and is economical and particularly suitable for determining the drug content in plasma and brain samples. The NP size is associated with the distribution patterns of nanodrugs. Therefore, a particular NP size can be selected to maximize the pharmacodynamics effects and control the toxicity of nanodrugs. [ABSTRACT FROM AUTHOR]