Mdn 0100

The microdialysis system consisted of a microdialysis syringe (1 mL, MDN-0100; BASi, Mt Vernon, IN, USA), a Bee syringe pump, and a fraction collector (CULEX fraction collector; BASi). Commercially available microdialysis probes (MD-2200; BASi) with membrane lengths of 5 and 2 mm were used for plasma and hippocampus sampling, respectively.
In vivo recovery was evaluated using a retrodialysis method, which measured the loss (extraction ratio) of LTG via the probe.23 (link) Microdialysis probes were implanted for plasma and hippocampus sampling as described in the “LTG concentration in plasma sampled by microdialysis” and “LTG concentration in the hippocampus sampled by microdialysis” sections; 1 μg/mL and 25 ng/mL of LTG were flushed via the blood probe and brain probe, respectively. The perfusate (Cperf) and dialysate (Cdial) concentrations of LTG were determined using HPLC and UPLC–mass spectrometry (MS). In vivo relative recovery (Rdial) of LTG across the microdialysis probe was calculated by the following equation: Rdial = (Cperf − Cdial)/Cperf.

A micro dialysis (MD) system composed of a microinjection pump (BASi MD-1001, West Lafayette, IN), micro syringe with a worker controller (BASi MDN-0100, 1 mL, West Lafayette, IN), Raturn system (BASi, West Lafayette, IN), and Honeycomb fraction collector (BASi MD-1201, West Lafayette, IN) was used. The linear MD probe had a 30 kDa cutoff with 320 µm OD.
Skin probe implantation: The rats with back hairs were shaved and fasted without water for a night before the experiment. The depilated rats were anesthetized intraperitoneal with 25% urethane (1 mL/100 g) (Hüske et al., 2016 (link)), and 2.5 cm of length was measured in the middle part of the skin on the back of the rats using a ruler. The probe implantation point and end point were marked with a marker pen, and a skin probe was used to guide the needle to puncture the skin. The skin probe was soaked with heparin sodium and inserted with the help of a guide needle. After the probe was implanted, the implant point and end point were fixed with a medical tape to prevent the probe from moving and the drugs from entering the damaged skin. To avoid the effect of tissue fluid, a flow rate of 1 μL·min⁻¹ was used for blank perfusion (30% ethanol was diluted with normal saline) after probe implantation, and the tissue was balanced for 45 min to recover to normal level (Voelkner et al., 2019 (link)).