Transcutaneous immunization via rapidly dissolvable microneedles protects against hand-foot-and-mouth disease caused by enterovirus 71.

Recent large outbreaks of hand-foot-and-mouth disease (HFMD) have seriously affected the health of young children. Enterovirus 71 (EV71) is the main causative agent of HFMD. Herein, for the first time, rapidly dissolvable microneedles (MNs) loaded with EV71 virus-like particles (VLPs) were evaluated whether they could induce robust immune responses that confer protection against EV71 infection. The characteristics of prepared MNs including hygroscopy, mechanical strength, insertion capacity, dissolution profile, skin irritation and storage stability were comprehensively assessed. EV71 VLPs remained morphologically stable during fabrication. The MNs made of sodium hyaluronate maintained their insertion ability for at least 3h even at a high relative humidity of 75%. With the aid of spring-operated applicator, EV71 MNs (approximately 500µm length) could be readily penetrated into the mouse skin in vivo, and then rapidly dissolved to release encapsulated antigen within 2min. Additionally, MNs induced slight erythema that disappeared within a few hours. More importantly, mouse immunization and virus challenge studies demonstrated that MNs immunization induced high level of antibody responses conferring full protection against lethal EV71 virus challenge that were comparable to conventional intramuscular injection, but with only 1/10th of the delivered antigen (dose sparing). Consequently, our rapidly dissolving MNs may present as an effective and promising transcutaneous immunization device for HFMD prophylaxis among children.

[Determination of seven toxaphene congeners in ginseng and milkvetch root by gas chromatography tandem mass spectrometry].

A novel method for the determination of representative toxaphene congeners in traditional Chinese herbal medicines was developed. Ginseng and Milkvetch Root were selected as the samples and seven toxaphene congeners were selected as the monitoring objects. The samples were extracted by accelerated solvent extraction with cyclohexane-acetone (9:1, v/v), then cleaned-up by Florisil solid phase extraction with hexane as the eluent and the residues were detected by gas chromatography-electron ionization tandem mass spectrometry (GC-EI-MS/MS) in multiple reaction monitoring (MRM) mode. The performance was demonstrated by the analysis of Ginseng and Milkvetch Root samples spiked with toxaphene congeners at three concentration levels of 0.005, 0.01 and 0.1 mg/kg. The recoveries ranged from 72.4% to 105% with the relative standard deviations (RSDs) of 0.96%-10.4%. The limits of detection (LODs) were 0.2-1.7 microg/kg. This method is sensitive and efficient in the aspect of extraction, and can be applied to monitor the residue of toxaphene congeners in Ginseng and Milkvetch Root.