Analysis of 2,4-Dinitrophenol in Postmortem Blood and Urine by Gas Chromatography-Mass Spectrometry: Method Development and Validation and Report of Three Fatalities in the United States.

2,4-dinitrophenol (2,4-DNP) is a compound used in the early 1900s as a weight-loss drug but later prohibited due to its severe adverse effects, including death. It has however been attracting interest, due to its weight-loss properties, and appears to be re-emerging in forensic casework. As 2,4-DNP is available for use in industry and as a pesticide and easily accessible online, the dissemination of this drug can be fast. The compound exerts its effects through inhibition of ATP synthesis, and corresponding thermogenic energy loss which can be fatal. A method for qualitative and quantitative analysis of 2,4-DNP in blood and urine specimens using GC-MS with hydrogen as carrier gas is described. The method was validated and displayed acceptable performance parameters with linearity (R2 higher than 0.998), inter-assay imprecision (lower than 10.6%), intra-assay imprecision (lower than 10.7%), and extraction efficiency (92.1%). Stability of 2,4-DNP in blood and urine was studied, and the drug was stable up to 30 days refrigeration or frozen. Six cases in United States suspected to be related to 2,4-DNP were analyzed. Three cases were found to be positive for 2,4-DNP. Concentrations of 2,4-DNP were in the range of 61.6-220 mg/L in urine and <3-114 mg/L in blood. Based on our findings, we suggest that medical examiners and forensic toxicologists be aware of the reappearance of 2,4-DNP, including this compound as a target in death investigations related to weight-loss drugs.

High fat diet aggravates the nephrotoxicity of berberrubine by influencing on its pharmacokinetic profile.

Berberrubine (BRB), the active metabolite of berberine (BBR), possesses various pharmacological activities. In this study, we found BRB showed not only a stronger lipid-lowering effect than berberine but also a specific nephrotoxicity in mice fed with high fat diet (HFD). To explore the underlying mechanism, the pharmacokinetics of BRB were evaluated. There was a greater in vivo exposure of BRB in C57BL/6J mice fed with HFD than with routine chows, in terms of Cmax, AUC0-t, levels of BRB in kidney and urinary excretion. Moreover, in vitro assessment clearly showed BRB had a toxic effect on renal cell lines, while the primary metabolite, berberrubine-9-O-ß-d-glucuronide (BRBG), did not show any obvious toxicity. These results suggested HFD aggravated BRB-induced nephrotoxicity by promoting the in vivo exposure of BRB especially in urine and kidney. Although our previous study indicated BRB could be metabolized into BRBG, BRBG did not show any obvious toxicity in vitro.

In vivo absorption and disposition of α-cedrene, a sesquiterpene constituent of cedarwood oil, in female and male rats.

This study aimed to evaluate the potential of α-cedrene as a new anti-obesity drug by characterizing absorption, metabolism and pharmacokinetics in rats. α-Cedrene was administered intravenously (10 and 20 mg/kg) and orally (50 and 100 mg/kg) to female and male Sprague-Dawley rats. Blood, tissues, urine, and feces were collected at predetermined times. α-Cedrene concentrations were determined by a validated gas chromatography-tandem mass spectrometry (GC-MS/MS). A gas chromatography-mass selective detection (GC-MSD) method was used to identify the major metabolite. After i.v. injection, α-cedrene exhibited a rapid clearance (98.4-120.3 ml/min/kg), a large distribution volume (35.9-56.5 l/kg), and a relatively long half-life (4.0-6.4 h). Upon oral administration, it was slowly absorbed (Tmax = 4.4 h) with bioavailability of 48.7-84.8%. No gender differences were found in its pharmacokinetics. Upon oral administration, α-cedrene was highly distributed to tissues, with the tissue-to-plasma partition coefficients (Kp) far greater than unity for all tissues. In particular, its distribution to lipid was notably high (Kp = 132.0) compared to other tissues. A mono-hydroxylated metabolite was identified as a preliminary metabolite in rat plasma. These results suggest that α-cedrene has the favorable pharmacokinetic characteristics to be further tested as an anti-obesity drug in clinical studies.

Absorption, distribution, metabolism, and excretion of dirlotapide in the dog.

Three once-daily oral doses of 0.2 mg/kg [(14)C]dirlotapide were administered to beagle dogs to study the absorption, distribution, metabolism, and excretion of dirlotapide. Mean (14)C recovered at 2.5 and 4.5 h after the last dose was 90%. Mean (14)C in urine, bile, and feces was <1%, 1.7%, and 56% of the dose, respectively. In tissues, 26% of the (14)C dose was present in the gastrointestinal tract, 6.0% in liver, and <1% each in kidney, gall bladder, heart, and brain. To further characterize drug disposition, a single 2.5-mg/kg oral dose of [(14)C]dirlotapide was administered to beagle dogs. More than 84% of the dose had been eliminated by 72 h in feces, with 21% of the dose present in feces as parent dirlotapide. Less than 1% of the dose was excreted in urine. In bile collected during the first 24-h postdose from three dogs, 32% and 11% of the (14)C dose was present in samples from male and female dogs, respectively. Based upon metabolite profiling of plasma, excreta, and bile samples, dirlotapide was extensively metabolized to more than 20 metabolites. Biliary/fecal excretion and the potential for enterohepatic recycling of metabolites are suggested.