Pharmacokinetics and absolute bioavailability of resveratrol solid dispersion in rats / 中草药

Objective To study the pharmacokinetics and pharmacokinetic parameter of resveratrol (RES) crude drug and solid dispersion (RES-PEG) in rats. Methods HPLC-UV was established for detecting plasma concentrations of RES and investigating its pharmacokinetics in rats with ig and iv administration. The software of DAS3.0 was used to process the pharmacokinetic parameters. Results The linear calibration curve was obtained in the range of (10-2.5 × 104) ng/mL for RES, and the lower limit of quantitation was 10 ng/mL. Intra- and inter- day precision for all samples were less than 5.1%, and the accuracy of three different concentrations was in the range from -1.1% to 0.7%. The extraction recovery of RES from rat plasma was from 97.8% to 104.1%. The main pharmacokinetics parameters of RES crude drug and RES-PEG after ig administration, and RES after iv administration were shown as follows: t1/2, (2.6 ± 2.0), (2.3 ± 0.8), and (6.3 ± 1.1) h; AUC 0-12, (514.7 ± 117.5), (1 084.6 ± 836.9), and (2 697.3 ± 289.8) ng∙mL/h, respectively; the Cmax of RES crude drug and RES-PEG after ig administration were (473.3 ± 200.8) and (814.1 ± 246.6) ng/mL, respectively. Compared to crude drug, the relative bioavailability of of RES-PEG was about 200%; And the absolute bioavailability of RES crude drug was 5%. Conclusion The oral bioavailability of RES was low. The relative bioavailability of RES crude drug was significantly improved after being prepared into solid dispersion.

Analysis of primary metabolites of ranolazine in dog urine by LC-MS(n) / 药学学报

Ranolazine and metabolites in dog urine were identified by LC-MS(n). Dog urine samples were collected after ig 30 mg x kg(-1) ranolazine, then the samples were enriched and purified through solid-phase extraction cartridge. The purified samples were analyzed by LC-MS(n). The possible metabolites were discovered by comparing the full scan and SIM chromatograms of the test samples with the corresponding blanks. Seventeen phase I metabolites and fourteen phase II metabolites were identified in dog urine. Three metabolites were identified by comparing with the control article. The metabolites were formed via the following metabolic pathways: O-demethylation, O-dearylation, hydroxylation, N-dealkylation, amide hydrolysis, glucuronidation and sulfation. The LC-MS(n) method is suitable for the rapid identification of drug and its metabolites in biologic samples.

Biomechanical comparison of double-row versus transtendon single-row suture anchor technique for repair of the grade III partial articular-sided rotator cuff tears / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>For partial-thickness tears of the rotator cuff, double-row fixation and transtendon single-row fixation restore insertion site anatomy, with excellent results. We compared the biomechanical properties of double-row and transtendon single-row suture anchor techniques for repair of grade III partial articular-sided rotator cuff tears.</p><p><b>METHODS</b>In 10 matched pairs of fresh-frozen sheep shoulders, the infraspinatus tendon from 1 shoulder was repaired with a double-row suture anchor technique. This comprised placement of 2 medial anchors with horizontal mattress sutures at an angle of ≤ 45° into the medial margin of the infraspinatus footprint, just lateral to the articular surface, and 2 lateral anchors with horizontal mattress sutures. Standardized, 50% partial, articular-sided infraspinatus lesions were created in the contralateral shoulder. The infraspinatus tendon from the contralateral shoulder was repaired using two anchors with transtendon single-row mattress sutures. Each specimen underwent cyclic loading from 10 to 100 N for 50 cycles, followed by tensile testing to failure. Gap formation and strain over the footprint area were measured using a motion capture system; stiffness and failure load were determined from testing data.</p><p><b>RESULTS</b>Gap formation for the transtendon single-row repair was significantly smaller (P < 0.05) when compared with the double-row repair for the first cycle ((1.74 ± 0.38) mm vs. (2.86 ± 0.46) mm, respectively) and the last cycle ((3.77 ± 0.45) mm vs. (5.89 ± 0.61) mm, respectively). The strain over the footprint area for the transtendon single-row repair was significantly smaller (P < 0.05) when compared with the double-row repair. Also, it had a higher mean ultimate tensile load and stiffness.</p><p><b>CONCLUSIONS</b>For grade III partial articular-sided rotator cuff tears, transtendon single-row fixation exhibited superior biomechanical properties when compared with double-row fixation.</p>