OBJECTIVE To establish a liquid chromatography massspectrometry(LC-MS/MS)method for quantitatively determining the concentration of cepharanthine in rat plasma and tissue samples after intravenous injection of cepharanthine hydrochloride.METHODS ①The LC-MS/MS method was adopted.A Phenomenex C18(3.0 mm×50 mm,2.6 μm)column was employed with a mobile phase consisting of 0.05%formic acid-2 mmol·L-1 ammonium acetate-water solution and 0.1%formic acid-acetonitrile solution under gradient elution at a flow rate of 0.6 mL·min-1.The determination was performed using positive ion multiple reaction monitoring mode assays:cepharanthine(m/z:607.3→365.1)and buspirone(IS)(m/z:386.4→122.2).② Blood samples were collected from 6 SD rats at different time points following a single iv administration of cepharanthine to determine the concentration of the drug.The main pharmacokinetic parameters were calculated using a non-compartmental model.③72 SD rats were subjected to tissue distribution experiments after a single and multiple iv administra-tion of cepharanthine,and tissue samples were collected at six different time points(n=6)for the quanti-fication of drug concentrations.④ The whole blood plasma distribution ratio(Rb/p)of cepharanthine hydrochloride(7.5 mg·kg-1)in 3 SD rats was determined 2 h after iv administration.⑤The protein binding of cepharanthine to rat plasma and lung tissue homogenates was determined by equilibrium dialysis before the concentration of the free drug within the lungs was calculated.RESULTS ① An LC-MS/MS method for quantitatively determining cepharanthine in rat plasma and tissue homogenates was devel-oped,which demonstrated an excellent linear relationship(r2>0.999)within the concentration range of 2 to 1000 μg·L-1,with a lower limit of quantification at 2 μg·L-1.The obtained results met all the require-ments for accurate quantitative detection.②The main pharmacokinetic parameters of cepharanthine in rats following a single iv administration were as follows:C0=(686.91±238.43)μg·L-1,t1/2=(29.70±6.29)h,Vz=(62.70±7.93)L·kg-1,Vss=(62.55±11.28)L·kg-1,CL=(1.50±0.23)L·h-1·kg-1 and AUC(0-t)=(4.52±0.61)h·mg·L-1.③ Concentrations in tissues exceeded those in plasma after both a single and multiple iv administration,with the highest levels in the lung.The values of AUC(0-t)in lungs were(2 547.35±156.56)and(4 481.35±479.21)h·mg·L-1 after a single and multiple iv administration,respectively.④ The content of cepharanthine in blood cells was higher than that in plasma,and Rb/p was 3.5±0.8.⑤ After correction by the protein-binding rate,the minimum concentration of free drugs in the lungs(95.04 μg·L-1)exceeded the reported antiviral activity threshold against coronaviruses(EC50=60.67 μg·L-1).CONCLUSION An LC-MS/MS method has been established to rapidly and sensitively determine the concentration of cepharanthine in rat plasma and tissues.Following intravenous administration of ceph-aranthine hydrochloride,the pulmonary exposure level of the drug is significantly higher in plasma and other tissues,providing data for evaluating its in vivo pharmacological activities.

OBJECTIVE To establish a liquid chromatography massspectrometry(LC-MS/MS)method for quantitatively determining the concentration of cepharanthine in rat plasma and tissue samples after intravenous injection of cepharanthine hydrochloride.METHODS ①The LC-MS/MS method was adopted.A Phenomenex C18(3.0 mm×50 mm,2.6 μm)column was employed with a mobile phase consisting of 0.05%formic acid-2 mmol·L-1 ammonium acetate-water solution and 0.1%formic acid-acetonitrile solution under gradient elution at a flow rate of 0.6 mL·min-1.The determination was performed using positive ion multiple reaction monitoring mode assays:cepharanthine(m/z:607.3→365.1)and buspirone(IS)(m/z:386.4→122.2).② Blood samples were collected from 6 SD rats at different time points following a single iv administration of cepharanthine to determine the concentration of the drug.The main pharmacokinetic parameters were calculated using a non-compartmental model.③72 SD rats were subjected to tissue distribution experiments after a single and multiple iv administra-tion of cepharanthine,and tissue samples were collected at six different time points(n=6)for the quanti-fication of drug concentrations.④ The whole blood plasma distribution ratio(Rb/p)of cepharanthine hydrochloride(7.5 mg·kg-1)in 3 SD rats was determined 2 h after iv administration.⑤The protein binding of cepharanthine to rat plasma and lung tissue homogenates was determined by equilibrium dialysis before the concentration of the free drug within the lungs was calculated.RESULTS ① An LC-MS/MS method for quantitatively determining cepharanthine in rat plasma and tissue homogenates was devel-oped,which demonstrated an excellent linear relationship(r2>0.999)within the concentration range of 2 to 1000 μg·L-1,with a lower limit of quantification at 2 μg·L-1.The obtained results met all the require-ments for accurate quantitative detection.②The main pharmacokinetic parameters of cepharanthine in rats following a single iv administration were as follows:C0=(686.91±238.43)μg·L-1,t1/2=(29.70±6.29)h,Vz=(62.70±7.93)L·kg-1,Vss=(62.55±11.28)L·kg-1,CL=(1.50±0.23)L·h-1·kg-1 and AUC(0-t)=(4.52±0.61)h·mg·L-1.③ Concentrations in tissues exceeded those in plasma after both a single and multiple iv administration,with the highest levels in the lung.The values of AUC(0-t)in lungs were(2 547.35±156.56)and(4 481.35±479.21)h·mg·L-1 after a single and multiple iv administration,respectively.④ The content of cepharanthine in blood cells was higher than that in plasma,and Rb/p was 3.5±0.8.⑤ After correction by the protein-binding rate,the minimum concentration of free drugs in the lungs(95.04 μg·L-1)exceeded the reported antiviral activity threshold against coronaviruses(EC50=60.67 μg·L-1).CONCLUSION An LC-MS/MS method has been established to rapidly and sensitively determine the concentration of cepharanthine in rat plasma and tissues.Following intravenous administration of ceph-aranthine hydrochloride,the pulmonary exposure level of the drug is significantly higher in plasma and other tissues,providing data for evaluating its in vivo pharmacological activities.

Objective:To compare the efficacy of double Z-shaped suture and modified Kessler suture in the repair of acute closed Achilles tendon rupture.Methods:A retrospective cohort study was conducted to analyze the clinical data of 27 patients with acute closed Achilles tendon rupture admitted to the Second Affiliated Hospital of Xi′an Jiaotong University from July 2018 to July 2022, including 24 males and 3 females, aged 14-53 years [(35.7±8.2)years]. All the patients underwent primary open surgical repair of the Achilles tendon, among whom 16 patients were treated with the double Z-shaped suture technique (double Z-shaped suture group) and 11 with the modified Kessler suture technique (modified Kessler suture group). Visual analogue scale (VAS) scores preoperatively and at 2, 4, and 6 weeks postoperatively as well as at the last follow-up were compared between the two groups. American Orthopedic Foot & Ankle Society (AOFAS) ankle-hindfoot scores, Achilles tendon total rupture scores (ATRS), ankle range of motion (dorsiflexion and plantarflexion angles), and shear wave elastography (SWE) [with its results recorded as shear wave velocity (SWV)] were applied to evaluate the recovery of tendon function and quality. High-frequency ultrasonography was also used to evaluate the recovery of morphological structure of the Achilles tendon and soft tissue adhesion. Tolerance to early rehabilitation at 2 weeks postoperatively and the incidence of postoperative complications were compared between the two groups.Results:All the patients were followed up for 6-12 months [(9.6±1.3)months]. There was no statistically significant difference in preoperative VAS scores between the two groups ( P>0.05). At 2, 4, and 6 weeks postoperatively, the VAS scores in the double Z-shaped suture group were 4.6(4.0, 5.0)points, 1.6(1.0, 2.0)points, and 0.5(0.0, 1.0)points respectively, significantly lower than those in the modified Kessler suture group [6.9(6.0, 8.0)points, 2.5(2.0, 3.0)points, and 1.4(1.0, 2.0)points] ( P<0.05 or 0.01). At the last follow-up, the VAS decreased to 0.0(0.0, 0.0)points in both groups. VAS score in the double Z-shaped suture group significantly decreased at 2 weeks postoperatively compared to that preoperatively, with a consistent downward trend observed at all the postoperative time points ( P<0.05). In the modified Kessler suture group, there was no significant difference in VAS scores preoperatively and at 2 weeks postoperatively ( P>0.05), but a downward trend was noted at 4 and 6 weeks postoperatively and at the last follow-up ( P<0.05). There were no significant differences in AOFAS ankle-hindfoot scores, ATRS or SWV at 2, 4, and 6 weeks postoperatively and at the last follow-up ( P>0.05). At 2, 4, and 6 weeks postoperatively, dorsiflexion angles in the double Z-shaped suture group were (-18.2±3.9)°, (-13.7±2.8)°, and (-6.6±2.4)° respectively, significantly better than those in the modified Kessler suture group [(-24.1±2.7)°, (-18.3±3.0)°, and (-12.0±2.8)°] ( P<0.01). No significant difference in dorsiflexion angles was observed between the groups at the last follow-up ( P>0.05). No significant differences in plantarflexion angles were noted at 2 weeks postoperatively and at the last follow-up ( P>0.05). At 4 and 6 weeks postoperatively, plantarflexion angles in the double Z-shaped suture group were (37.5±3.8)° and (42.1±3.3)°respectively, significantly better than those in the modified Kessler suture group [(34.6±2.0)° and (38.0±1.4)°] ( P<0.05 or 0.01). Both groups showed increasing trends in AOFAS ankle-hindfoot scores, dorsiflexion and plantarflexion angles, and SWV at 4 and 6 weeks postoperatively, as well as at the last follow-up ( P<0.05 or 0.01). No significant differences were noted in ATRS at 2 and 4 weeks postoperatively in the double Z-shaped suture group ( P>0.05), but significant improvements were observed at 6 weeks postoperatively and at the last follow-up ( P<0.05 or 0.01). In the modified Kessler suture group, no significant changes in ATRS scores were observed at 2, 4 and 6 weeks postoperatively ( P>0.05), except a significant increase at the last follow-up ( P<0.05). High-frequency ultrasonography at 2, 4, and 6 weeks postoperatively as well as at the last follow-up indicated good morphological recovery of the Achilles tendon in both groups, while soft tissue adhesion was significantly less in the double Z-shaped suture group compared with that of the modified Kessler suture group. Thirteen patients (81.3%) in the double Z-shaped suture group and 3 patients (27.3%) in the modified Kessler suture group were observed to tolerate the early rehabilitation at 2 weeks postoperatively as scheduled in the rehabilitation plan ( P<0.05). There was no statistically significant difference in the incidence of postoperative complications between the groups ( P>0.05). Conclusion:Compared with the modified Kessler suture technique, the double Z-shaped suture technique can reduce postoperative pain at an early stage, enhance the restoration of ankle joint mobility, lower the risk of postoperative soft tissue adhesion, and improve tolerance to rehabilitation in the repair of acute closed Achilles tendon rupture.