Effect of hemopurification on acute chlorfenapyr poisoning / 中华急诊医学杂志

Objective:To evaluate the therapeutic effect of hemopurification on acute chlorfenapyr poisoning according to the blood concentration of chlorfenapyr and to provide experience for clinical treatment.Methods:Two patients who presented to our Emergency Department following an ingestion of chlorfenapyr and then were treated with hemopurification in 2022 were included. The concentrations of chlorfenapyr and its highly toxic metabolite tralopyril were dynamically monitored, and the clinical data of the patients were collected.Results:Case 1 was given hemoperfusion for the first time 13 hours after ingestion. During l hour hemoperfusion, the tralopyril decreased by 28.82%. The concentration increased and exceeded the pre-perfusion level after 2 hours of hemoperfusion. After three times of hemoperfusion, the concentrations of chlorfenapyr and tralopyril were still higher than those before the first time, reaching 248 ng/mL and 1 307 ng/mL respectively. The concentration of chlorfenapyr showed a downward trend after 130 h, and the tralopyril in blood reached the peak 3 164 ng/mL at 130 h and decreased to 2 707 ng/mL at 178 h. In case 2, the blood chlorfenapyr and tralopyril concentration was 392 ng/mL and 7 598 ng/mL respectively 150 hours after ingestion. The blood chlorfenapyr concentration decreased by 37.75% respectively after first hemoperfusion, and the tralopyril concentration decreased by 38.02% respectively. During 85 hours of continuous veno-venous hemodiafiltration (CVVHDF), the concentration of tralopyril was maintained at 4 234~6 410 ng/mL. Case 1 was followed up to 12 days and lost follow-up. Case 2 died and the survival time was 247 hours.Conclusions:Hemoperfusion can scavenge tralopyril, but CVVHDF has poor scavenging ability for tralopyril. And the apparent volume of distribution (Vd) of chlorfenapyr and tralopyril are large. After ingestion, chlorfenapyr spreads to various tissues quickly, and it is easy to accumulate in the adipose tissue. The chlorfenapyr in the tissue slowly is released back to the blood and stays in the blood for a long time. The peak concentration of chlorfenapyr appeared earlier than that of tralopyril. Clinicians should pay attention to the early removal of toxins from the digestive tract.

Validated analytical study of the effect of Lycopene on the pharmacokinetics of Paracetamol and Chlorzoxazone in rats

Lycopene was reported to influence some cytochrome P450 enzymes activity. The present study investigates the effect of lycopene on the pharmacokinetics of paracetamol and chlorzoxazone. Lycopene (20 mg/kg) was intra-peritoneally administered to two groups of rats for eight consecutive days and two other groups were given vehicle. On the eighth day, chlorzoxazone and paracetamol were separately intravenously administered to a lycopene group and a control group. Blood samples were collected at different time intervals, treated and analyzed using HPLC. The HPLC method used for paracetamol analysis was based on isocratic elution using a mobile phase consisting of water: methanol, (77:23 v/v) at a flow rate 1 mL min−1, Kromasil C18 column, and UV detection at 254 nm using caffeine as internal standard. About chlorzoxazone, separation was carried out using water: acetonitrile (60: 40, v/v) as the mobile phase at a flow rate 1 mL min−1, Inertsil ODS-3 C18 column, UV detection at 283 nm and esomeprazole as internal standard. Statistical analysis of the pharmacokinetic data using student t test showed a significant increase in AUC 0-t , AUC 0-Inf and t1/2 of paracetamol (P<0.05) and of chlorzoxazone (P<0.05) in the groups pretreated with lycopene (20 mg/kg), significant increase in the volume of distribution of paracetamol (P < 0.05), but no significant difference in that of chlorzoxazone. In other words, paracetamol and chlorzoxazone showed significant decrease (P < 0.05), respectively. These results demonstrate that treatment of rats with Lycopene (20mg/kg, ip) has a significant effect on the metabolic clearance and the pharmacokinetics of both drugs

An algorithmic method for mean residence time in central compartment / 中国药学杂志

OBJECTIVE: To provide a method for calculating mean residence time of drugs in central compartment (MRTC).