Influence factors of microdialysis linear probe recovery for in vivo and in vitro cyclophosphamide calibration by HPLC-MS/MS / 国际药学研究杂志

Objective To establish an optimal linear probe recovery correction method for in vivo and in vitro cyclophosphamide. Methods with ringer solution as the perfusion, retrodialysis gain and loss method were used to calibrate the linear probe. The impact of different perfusion flow rates on microdialysis relative recovery for cyclophosphamide was investigated by HPLC-MS/MS. Results When the perfusion was 1.0μl/min, in vitro recovery results were in the range of (24.11±1.75)%to (50.93±0.91)%for the gain method, and(26.19±0.76)% to(53.31±1.23)% for the loss method;recovery results in vivo were(26.19±0.76)%. Conclusion Cyclophosphamide is suitable for microdialysis sampling. This experiment calibration method is simple and effective.

Pharmacokinetics of scopolamine hydrobromide oral disintegrative microencapsule tablets in Beagle dogs determined with LC-MS/MS / 药学学报

The study aims to elucidate the characteristics of pharmacokinetics of scopolamine hydrobromide oral disintegrative microencapsule tablets in healthy Beagle dogs. Chromatographic separation was performed on a C18 column (100 mm x 3.0 mm, 3.5 microm) with methanol - 2 mmol x L(-1) ammonium formate (25 : 75) as the mobile phase. A trip-quadrupole tandem mass spectrum with the electrospray ionization (ESI) source was applied and positive ion multiple reaction monitoring mode was operated. Six Beagle dogs were randomly devided into two groups. They received oral single dose of scopolamine hydrobromide oral disintegrative microencapsule tablets 0.6 mg (test tablet) or scopolamine hydrobromide normal tablets (reference tablet). Plasma samples were collected at designed time. Plasma concentration of scopolamine hydrobromide was determined by LC-MS/MS and pharmacokinetic parameters were calculated. The pharmacokinetic parameters of test tablet vs reference tablet were as follows: C(max): (8.16 +/- 0.67) ng x mL(-1) vs (3.54 +/- 0.64) ng x mL(-1); t1/2: (2.83 +/- 0.45) h vs (3.85 +/- 0.82) h; t(max): (1.25 +/- 0.27) h vs (0.42 +/- 0.09) h; AUC(0-12h): (25.06 +/- 3.75) h x ng x mL(-1) vs (9.59 +/- 1.02) h x ng x mL(-1); AUC(0-infinity): (26.30 +/- 3.92) h x ng x mL(-1) vs (10.80 +/- 1.45) h x ng x mL(-1); MRT(0-12h): (3.38 +/- 0.34) h vs (3.86 +/- 0.26) h; MRT(0-infinity): (3.98 +/- 0.63) h vs (5.37 +/- 1.00) h. The absorption rate and AUC of test tablet is different from that of reference tablet. The bioavailability of test tablet is better than those of reference tablet.

Pharmacokinetics of levofloxacin in rat pancreas / 中华胰腺病杂志

Objective To investigate the pharmaeokinetics of levofloxacin in rat's pancreatic tissue. Methods Pancreatic tissue and blood were sampled in vivo by microdialysis simultaneously. The concentrations of levofloxacin in beth blood and tissues were measured by high performance liquid chromatography. All date were analyzed by WinNonlin software. Results The maximum concentration of free levofloxacin in blood and pancreatic tissue were (65.23 ± 12.9) μg/ml at 10min and (30.56±3.22) μg/ml at 20 min, respectively, then beth continuously decreased. Concentration of free levofloxacin in pancreatic tissue was higher than that in blood from 20min to 100min, then returned to similar level. The area under the concentration curve(AUC)of unbound levofloxacin was(2465.11±258.56)min·μg~(-1)·ml~(-1) in pancreas,and (2914.38±205.73)min·μg~(-1)·ml~(-1) in blood.Conclusions Microdialysis with reversed phase high performance liquid chromatography established in this essay could be used to determine the pharmacokinetics of levofloxacin objectively. High concentration of levofloxacin in pancreatic tissue and blood was observed.