Buprenorphine and Norbuprenorphine Plasma Concentrations After High Dose IV Drug Administration
Marilyn A. Huestis*, Annie Umbricht, Kenzie L. Preston, Edward J. Cone
Intramural Research Program, NIDA, NIH, Baltimore, MD, USA
Buprenorphine (BUP), a partial a agonist used for analgesia and for treatment of opioid dependence, produces morphine-like pharmacodynamic effects but with a ceiling on many of its effects including respiratory depression in humans, suggesting an improved safety profile for BUP as compared to other opioid agonists. BUP is N-dealkylated by hepatic cytochrome P450 to norbuprenorphine (NBUP), which has an analgesic activity 2% that of BUP.
The present study was conducted to characterize the time course of appearance, peak and elimination of BUP and NBUP in plasma following intravenous (IV) and sublingual (SL) administration. BUP abuse by the IV route has been reported. Six healthy male non-dependent opioid users participated in this dose-escalation single-blind, double-dummy study. Placebo or 12 mg SL BUP was held under the tongue for 5 min followed by IV placebo or active BUP over 1 min. BUP and NBUP were detected in the first specimen collected 5 min after IV dosing in all subjects and following all doses. Plasma was collected for up to 72 h following IV administration of placebo, 2, 4, 8, 12, 16 mg BUP and after 12 mg SL BUP.
BUP and NBUP plasma concentrations were determined on a Finnigan TSQ 7000 triple quadrupole mass spectrometer utilizing deuterated BUP and NBUP internal standards and extraction with n-butyl chloride:acetonitrile (4:1) at pH 10. BUP, but not NBUP, was always detected in the first specimen following the 12 mg SL dose. Mean +/- SEM peak BUP occurred 5 to 10 minutes after drug and were 19.3 +/-0.9, 44.3 +/- 4.9, 85.2 +/- 7.7, 107.9 +/- 21.5, 134.0 +/- 22.2 ng/ml after the 2, 4, 8, 12 and 16 mg IV doses, respectively. Thirty min after 12 mg SL BUP, a mean peak of 10.6 +/- 1.6 ng/ml was measured (approximately 10% of the 12 mg IV peak).
BUP was detected in plasma at a 0.1 ng/ml limit of detection (LOD) for 24 to 72 h after the lowest IV doses. BUP concentrations at 72 h ranged from 0.1 to 0.4 ng/ml after the 8, 12 and 16 mg IV doses. After 12 mg SL BUP, parent drug was detected at a mean concentration of 0.2 ng/ml in 5 of 6 subjects at 72 h. Mean NBUP peak concentrations increased from 0.6 to 3.7 ng/ml dose-dependently and were noted 5 to 10 min after drug. The mean peak NBUP concentration was 0.8 ng/ml at 30 min after 12 mg SL BUP and 3.1 ng/ml at 5 to 10 min after 12 mg IV BUP. NBUP was detected at an LOD of 0.1 ng/ml for only 2 h after 2 mg IV, 24 h following 4 mg IV, 48 h after 8 mg IV and 72 h after 12 and 16 mg IV BUP.
Individual variations were noted in the time at which NBUP/BUP>1. In 4 of 6 cases, NBUP/BUP was never or rarely >1, while in 2 of 6 cases, NBUP/BUP>1 occurred 24 to 48 h after all BUP doses. These data document that previously demonstrated ceiling effects are most likely due to pharmacodynamic rather than pharmacokinetic adaptations. However, individual differences in P450 metabolism may be important as NBUP has been shown in rats to have a greater respiratory depressant effect than BUP.
Keywords: Buprenorphine, Norbuprenorphine, Plasma, Intravenous Administration.
Differentiation of Illicit Heroin Abuse from use of Prescribed Diamorphine using Electron Impact Gas-Chromatography Mass Spectrometry
Neil A. McLachlan-Troup, Susan Paterson, Sunella L. Brahma* and Bruce Trathern
Toxicology Unit, Imperial College, St. Dunstan's Road, London W6 8RP, UK
The metabolites of the opiate alkaloids papaverine and noscapine were investigated as potential markers for illicit heroin abuse in subjects prescribed pharmaceutical diamorphine. Over one thousand urine samples were collected from subjects attending drug treatment centers over a period of three months, including over one hundred samples from subjects prescribed diamorphine. The urine samples were analysed using a method involving solid phase extraction using mixed-mode cartridges, formation of trimethylsilyl derivatives, and analysis by gas chromatography-mass spectrometry (electron impact) run in scan mode. Four demethylated and two didemethylated papaverine metabolite derivatives were commonly detected in urine samples also containing morphine. In 51 urine samples from subjects not prescribed diamorphine which were positive for morphine and 6-monoacetylmorphine, thus indicating illicit heroin abuse, 50 (98%) were also positive for papaverine metabolite. Two noscapine metabolites were also detected with a lower frequency than papaverine metabolites.
Papaverine and noscapine metabolites were shown to be potential markers for illicit heroin abuse with longer detection times than 6-monoacetylmorphine.
Keywords: Heroin Abuse, Diamorphine Use, Markers.
Screening for the General Unknown in Tissue Samples by Polystyrene Resins
Thomas Stimpfl* and Walter Vycudilik
Institute of Forensic Medicine, University of Vienna, Senseng. 2, A-1090 Vienna, Austria
One of the main objectives of forensic toxicological analysis is the identification of a general unknown poison in biological material.
For urine and serum samples liquid/liquid extraction has proved to be convenient, but these specimens are not always available. On the other hand liquid/liquid extraction is difficult to adapt to the clean up of tissue samples, since a prevailing quantity of proteins could undergo denaturation resulting in adsorption of interesting compounds.
In our study polystyrene resins like OASISa (Waters Corp.) and Amberlite XADa (Rohm and Haas Comp.) were used to isolate low molecular lipophilic substances from tissue samples. The application of colloidal solutions prevented any disorder of the native structure of proteins that could have led to insufficient extraction yield. Moreover the exclusion of lipoids by the molecular sieve effect of Amberlite XADa
-4 decreased the 'chemical noise' registered by the detection system.
Analyses were performed in post mortem samples of blood, liver and brain by gas chromatography/mass spectrometry. The recovery of a reference solution recommended by DFG (Deutsche Forschungsgemeinschaft) was determined to evaluate the method. To improve the reproducibility ASPEC XL (Gilson Comp.) was utilised to automate main parts of the procedure.
The resulting method makes it possible to isolate general unknown poisons from tissue samples.
Optimisation of Solid Phase Microextraction (SPME) Conditions for Headspace Analysis of Organo-Phosphate Pesticides in Whole Blood
Kamarruddin Asri*1 and Robert A. Anderson2
1Department of Chemistry, Jalan Sultan, Petaling Jaya, Selangor, Malaysia
2Department of Forensic Medicine and Science, University of Glasgow, Glasgow G12 8QQ, UK
Organo-phosphate (OP) pesticides are a significant cause of fatal poisoning in many countries. Problems exist in detecting the parent substances in autopsy blood when putrefaction has occurred. This study evaluated the use of SPME as an extraction technique for the analysis of OP pesticides in whole blood.
Malathion and diazinon were used as model compounds, added to whole blank blood. Parameters affecting the adsorption of analyte on the SPME fibre were sampling time, temperature, agitation, modification of the ionic strength and pH. The best conditions for extraction were at 90°C, with a conditioning time of 10 minutes, exposure time of 30 minutes and desorption time of 5 minutes. All samples were agitated during the extraction process. The primary detection and quantification technique was GC-NPD but GC-MS was also used as a confirmatory identification technique. The minimum detectable level by GC-NPD was 100 ng per 0.5-ml whole blood and the linear quantifiable range was from 200 to 1000 ng per 0.5-ml whole blood (correlation coefficient 0.993). Recoveries were approximately 0.39 % with a coefficient of variation of 6.8%.
The rates of in vitro change of malathion concentrations in blood during storage at ambient temperatures in the range 20-25°C and at 4°C were also measured. The time limit of detection at 20-25°C was 4 hr but at 4°C was more than 11 days. No interferences from the putrefying blood were observed. From the results it was concluded that headspace-SPME could be used as an alternative technique for sample preparation which is simpler and more rapid than liquid-liquid extraction or conventional solid phase extraction.
Keywords: Solid Phase Microextraction, Organo-phosphates, Whole Blood.
Amantadine Intoxication: Disposition of Amantadine in a Fatal Overdose and Review of the Literature
Amanda J. Jenkins and Gary Sebrosky
Cuyahoga County Coroner's Office, 2121 Adelbert Road, Cleveland OH 44106, USA
Amantadine is a tricyclic primary amine available since 1964 for the treatment of the symptoms of Parkinson's disease and as an antiviral agent. It has been used in the treatment of influenza A virus and hepatitis C. More recently this drug has been used to treat fatigue in multiple sclerosis patients to reduce catatonic symptoms in neuroleptic free akinetic catatonic patients; in the treatment of chronic brain injury following trauma; and in the treatment of anti-depressant induced sexual dysfunction. Further, its potential use to facilitate opioid and cocaine abstinence in opioid dependent cocaine users has been reported. Amantadine has dopaminergic activity and is considered an NMDA antagonist. When utilized as an antiviral agent the usual adult daily dose is 200 mg as a single or divided dose. When used to treat the symptoms of Parkinsonism the typical dose is 100 mg two times a day. Therapeutic concentrations are in the range of 0.3-1 mg/l. Toxicity may be observed at blood concentrations exceeding 1-5 mg/l. Adverse reactions include agitation, depression, psychosis, disorientation, hallucinations, tremors, seizures and coma.
We report a case in which an individual died from amantadine intoxication. The deceased was a 39 old white male, weight 262 lbs (118 kg), and height 67 (170 cm), who was found dead at home. He had a history of ethanol abuse and was being treated for schizophrenia at the time of death. The medications prescribed were fluphenazine and amantadine. An autopsy was performed and blood, urine, liver and gastric contents were submitted for toxicological analysis. Autopsy findings included hypertrophic cardiomyopathy with coronary and intramyocardial vascular sclerosis, mild multifocal interstitial myocardial fibrosis, and cardiomegaly; and hepatocellular steatosis. Amantadine was analyzed by liquid/liquid extraction followed by gas chromatographic analysis with nitrogen phosphorus detection. Briefly, calibrators at concentrations of 0, 0.5, 1, 5, and 10 mg/l and case specimens were extracted with 6N sodium hydroxide and ethyl acetate. Pheniramine was utilised as internal standard. Following back extraction of the organic layer with acid and alkalinization with sodium hydroxide, the drug was extracted into dichloroethane and extracts injected onto the GC. The assay was linear over the concentration range tested with a correlation coefficient of > 0.999 and slope of 0.2998. Case specimens were diluted when necessary to ensure quantitation within the linearity of the assay. Amantadine was confirmed by gas chromatography/mass spectrometry. The following concentrations of amantadine were measured in this case:
|Amantadine (mg/l or mg/kg)
The concentration of amantadine measured in the blood of this case is similar to the average blood concentration reported in the literature from 3 cases of suicidal ingestion. In other cases, elevated blood levels and associated toxicity have been due to renal failure and resultant accumulation of drug.
Keywords: Amantadine Intoxication, Parkinson's Disease, Antiviral agent.
Venlafaxine - Analytical Findings in Clinical and Post-mortem Cases
Daniel Martinez*, Manjit Ruprah
Medical Toxicology Unit, Guys and St Thomas' Hospital Trust, Avonley Road, London SE14 5ER, UK
Venlafaxine is a new class of antidepressant agent which was introduced into Britain during 1995. The drug is a bicyclic phenylethylamine derivative unrelated in structure to other antidepressants such as the tricyclics, quadracyclics and MAOIs. Since venlafaxine is a selective serotonin and noradrenaline re-uptake inhibitor, it has been suggested that it should be safer in overdose relative to other antidepressants.
Clinical and post-mortem cases with suspected venlafaxine poisoning as well as cases involving patients undergoing antidepressant therapy with venlafaxine were investigated. Venlafaxine was measured in plasma and post-mortem blood samples using GC-NPD to derive information on therapeutic, overdose and fatal concentrations. Specimens from the clinical overdose and fatal cases were also screened for the presence of a wide range of other drugs.
In therapy, plasma venlafaxine and o-desmethylvenlafaxine levels ranged from 0.02-1.13 mg/l and 0.1-0.9 mg/l, respectively. In the clinical overdose cases, levels for venlafaxine and o-desmethylvenlafaxine ranged from 4.1-14.2 mg/l and 0.9-4.9 mg/l respectively. Symptoms recorded in these cases included sinus tachycardia, fitting, vomiting, drowsiness, confusion and slurred speech. In the fatal cases the venlafaxine and o-desmethylvenlafaxine levels ranged from 1-28 mg/l and 1-5 mg/l, respectively. There was a significant overlap in venlafaxine concentrations between the clinical overdose and fatal cases. In a case where ante-mortem and post-mortem samples were available, there was evidence of extensive post-mortem redistribution.
Keywords: Venlafaxine, Overdose, Therapy.
Mass Spectral Characterisation of Hepatic Cell Metabolites of D,L-kavain using HPLC and GC/MS Systems
Fuad Tarbah*, Hellmut Mahler, Oliver Temme and Thomas Daldrup
Institute of Legal Medicine, Heinrich-Heine-University P.O. Box 10 10 07, D-40001, Duesseldorf, Germany
The hepatic metabolism of D,L-kavain was studied in Hep-G2 cell cultures using a dose of 60 mg kavain in 200 ml culture media after incubation at 37°C for 70 hrs. DMSO was added to improve the solubility of kavain in the culture media and to increase its permeability through the cell membrane. Aliquots of samples were collected at 6 different times. The cell culture reactions were inactivated by addition of 25% methanol. Samples were stored at -60°C until analysis.
The samples were extracted by liquid/liquid extraction using dichloromethane/ether (7:3) at pH 9 (1). The extracts were reconstituted in methanol and fractionated by HPLC using a acetonitrile/water solvent gradient. About 23 fractions were collected and evaporated under a stream of nitrogen till dryness. The residues were dissolved in methanol and reanalysed by GC/MS before and after derivatisation (methylation and silylation). The analysis of the Hep-G2 cell culture media extracts revealed at least three different metabolites of kavain. Three derivatives of the metabolites could be identified after methylation as well as two after silylation.
1. F.A Tarbah, T. Daldrup. Fluid fluid extraction method for general unknown drug screening using an organic mixture of dichloromethane/diethyl ether. Medicina Legalis Baltica, 8, 1997 (1997).
Keywords: Kavain, Hep-G2 Cell, GC/MS.
Quantitative Determination of Paraquat by HPLC-DAD following Chemical Reduction with Sodium Borohydride in a Fatal Intoxication
Katrien Arys*, J. Van Bocxlaer, E. Meyer, K. Clauwaert, W. Lambert, M. Piette1, C. Van Peteghem and A. De Leenheer
Laboratorium voor Toxicologie, Universiteit Gent, Faculteit Farmaceutische Wetenschappen, Harelbekestraat 72, B-9000 Gent, Belgium
1Laboratorium voor Gerechtelijke Geneeskunde, Faculteit Geneeskunde, Universiteit Gent, J. Kluyskensstraat 29, B-9000 Gent, Belgium
The analysis of the postmortem blood, urine, and stomach contents of a fifty-year old male found dead at home, with routine screening and chromatographic methods, disclosed the presence of tricyclic antidepressants (0.49 mg/l in urine only), benzodiazepines (0.9 mg/l blood; 0.3 mg/l urine), cotinine (3.4 mg/l blood; 0.3 mg/l urine), caffeine (0.5 mg/l blood; 0.1 mg/l urine), diethyl parathion (0.1 mg/l urine; 187.2 mg/l stomach contents), and mevinphos (61.0 mg/l blood; 19.0 g/l stomach contents).
This report focuses on the main cause of this deadly intoxication i.e. paraquat, together with the complications in its detection. Although both mevinphos and diethyl parathion will have contributed to the cause of death, our explorative research described here was limited to paraquat.
Identification and quantitation of paraquat was performed in all postmortem samples available using a gradient HPLC system and photodiode-array detection. Sample preparation involved a protein precipitation step using trichloroacetic acid, followed by a chemical reduction with sodium borohydride of the fully ionised paraquat to a non-charged diene. After solvent extraction, separation of paraquat and the internal standard (ethyl paraquat) was achieved on a Merck Aluspher 100 RP-select B column with an alkaline mobile phase. The within-day coefficients of variation, obtained in spiked blood and urine samples (5.00 mg/l) were, 2.7 and 10.7%, respectively. The lower limit of detection in blood and urine were 63 and 32 µg/l,respectively. Concentrations of paraquat above 5 mg/l were measured in both blood (5.05 mg/l) and urine (6.00 mg/l), while massive amounts were demonstrated in stomach contents (17.20 g/l). Only a low amount was detected in liver (4.86 mg/kg), in contrast to the high concentration found in kidney (80.60 mg/kg). This can be explained by a short survival time after the fatal ingestion, thus not only preventing a complete absorption but also resulting in an incomplete distribution of paraquat.
Keywords: Paraquat, Postmortem Concentrations, HPLC.
Methamphetamine from Thailand with the Logo WY
Werner Bernhard*, Priska Regenscheit, Beatrice Hayoz, Alain Broillet, Beat Aebi, Michael Frost1, Justus Beike1
Institute of Legal Medicine, University of Bern, Buehlstrasse 20, CH-3012 Bern, Switzerland
1Institute of Legal Medicine, University of Munster, Von-Esmarch-Str. 62, D-48149 Munster, Germany
The seizure of approximately 27000 Methamphetamine pills with the logo WY at Zurich airport last year and further smaller seizures in Switzerland appear to be the tip of an iceberg. The WY pills were imported from Thailand where they are produced in quantities of several millions. In contrast to most dl-Methamphetamine pills encountered (and produced) in Europe, the WY pills contained d-Methamphetamine.
Materials and methods: (2-Hydroxy)-propyl-b-cyclodextrin (HP-b-CD) were obtained from Cyclolab (Budapest, Hungary). (-)-Methamphetamine and (+)-Methamphetamine were purchased from Sigma Chemicals (Deisenhofen, Germany).
Capillary electrophoresis (CE) conditions and sample preparation: Chiral separations were carried out using a P/ACE 5510 capillary electrophoresis system (Beckman, Fullerton, CA, USA) with a diode array detector. An uncoated fused-silica capillary (47 cm total length, 40 cm effective length, 50 µm I.D.) was used. The capillaries were treated before use by rinsing for 20 min with 0.1 M NaOH and before each sample with 0.1 M NaOH and rinsing buffer for 1 min. Separations were carried out using a 100 mM KH2PO4 buffer at pH 3.0 after rinsing the capillary for 2 min with the same buffer containing 15 mM (2-Hydroxy)-propyl-b-cyclodextrin (HP-b-CD). The applied voltage was 25 kV and the temperature was maintained at 20°C. Sample introduction was performed by hydrodynamic injection for 5 sec. Detection was performed at 200 nm. Beckman P/ACE station software 1.0 was employed for data conversion and evaluation. For sample preparation tablets were homogenized to a fine powder and 100 mg was dissolved in 0.01 M HCl for 10 min in an ultrasonic bath. After centrifugation an aliquot was diluted 1:10 with distilled water for analysis. Quantitation was done by HPLC.
Results of chemical analyses of the WY pills:
|Illicit drug d-Methamphetamine 25% e.g. 22.5 mg per pill (1012 reddish WY pills)
|d-Methamphetamine 22% e.g. 20.0 mg per pill (12 green WY pills)
|d-Methamphetamine 24% e.g. 19.0 mg per pill (80 reddish WY pills)
|d-Methamphetamine 26% e.g. 26.0 mg per pill (26 reddish WY pills)
|d-Methamphetamine 19% e.g. 19.0 mg per pill (8 reddish WY pills)
- Adulterant Caffeine
- Weight 80 to 100 mg per pill
- Diameter 6mm
- Thickness 2.8 to 3.4 mm
- Shape round biconvex
- Color reddish and approx. 1% are green
- Logos Up till now 4 different WY logos have been observed in Switzerland
The presence of only d-Methamphetamine in the pills is proof of partial synthesis starting with presumably l-Ephedrine (or d-Pseudoephedrine) as a precursor. The less potent dl-Methamphetamine is created by way of a fully synthetic route.
We present case reports and the analytical methods applied to characterize Methamphetamine pills.
Keywords: Methamphetamine, Chiral Separations, Capillary Electrophoresis, l-Ephedrine.
'Phenethylamine' Street Samples Encountered on the Belgian Drug Market
Inge Dirinck*, Willy Lambert and Andreas De Leenheer
Laboratory of Toxicology, Universiteit Gent, Harelbekestraat 72, B-9000 Gent, Belgium
Phenethylamines, a group of structurally related compounds with amphetamine as the basic compound remain very popular among recreational drug users for their stimulating and mood-modifying properties. Many of these phenethylamines have become controlled substances and are illegally synthesized in various clandestine laboratories throughout Europe and the United States. New, closely related derivatives are constantly developed in order to create new pharmacological properties, evade drug legislation or circumvent governmental control on precursor products. Unambiguous identification of these phenethylamines in street samples is essential for the successful prosecution of designer drug cases in a court of law, but is also interesting from a pharmacological-toxicological point of view.
478 Street samples (260 powders, 197 tablets and 21 other dose forms confiscated by Belgian law enforcement authorities in the period 1991-1998) were analyzed by gas chromatography-Fourier transform infrared spectrometry (GC-FTIR). Aliquots of methanolic solutions of the exhibits were analyzed with PTV-injection on an HP-1 column. The obtained vapour-phase FTIR spectra were submitted to a spectral search on a laboratory-made 'phenethylamine' library. Quantitative GC-FTIR analyses were performed after derivatization with heptafluorobutyric anhydride.
Several phenethylamine analogues were identified in the confiscated dose forms using this approach. Some of these phenethylamines - a-phenethylamine, N-methyl-a-phenethylamine, 4-bromo-2,5-dimethoxyphenethylamine ('2C-B' or 'Nexus') and N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamide (MBDB) have up to now not been controlled under Belgian drug legislation. The identification of a-phenethylamine and its N-methyl derivative supports the hypothesis that a new class of so-called 1-phenethylamines is synthesized in European basement chemistry labs. A computerized street sample database (Microsoft Access® 97) has been developed (available on CD-ROM for forensic institutes and law enforcement authorities). The database contains GC-FTIR analysis results (in some cases also additional GC-MS results) of the street samples regarding phenethylamines and other interesting compounds such as by-products, impurities, filling agents and adulterants, in combination with the ballistic characterization of the dose forms (visual color, description of tablet logos including logo pictures and EDU logo numbers, dimensions, geometry, score type, etc.).
Keywords: Street samples, Phenethylamines, GC-FTIR.
Reliability of Clinical Decisions Regarding Alcohol Influence
Hasn A. Abder-Rahman, K. A. Hadidi, Abdekkader H. Battah
Forensic Medicine and Toxicology Division, Faculty of Medicine, University of Jordan, Amman, 11942 Jordan
In general, discussing problems related to alcohol in countries where alcohol intake is socially unacceptable is also considered a sensitive issue. Pursuing legal procedures is usually dependent on a clinical judgement. This study was carried out to evaluate physicians' clinical decisions concerning patients suspected to be under the influence of alcohol. For this purpose 104 cases with positive blood alcohol concentration (BAC) were studied over 2 years period. They constituted 12.6% n=104 out of 825 medico-legal cases studied in this period. A small number of these cases can be diagnosed clinically (21.1%). Most of the diagnoses were achieved by having a positive history of alcohol intake (68.2%). The majority of diagnosed cases had a BAC of 50-100-100mg/dl. Moreover, a high admission rate was seen when BAC was <50mg/dl and BAC >150 mg/dl which constituted 39.3% and 48.5% of the admitted cases respectively. A large number of the admitted cases has either no trauma or simple trauma such as wounds (n=16, 48.4%) as compared to the control group of cases n=10, 21.8%. Accordingly, it is concluded that clinical decisions in BAC cases are usually unreliable. Miscarriage of justice could have resulted in these cases due to physicians' misdiagnosis or misjudgement. Finally it is recommended in countries which are not considering BAC in their law, to start implementing a certain BAC level for the proper application of law as in other countries.
Keywords: Alcohol, Reliability, Clinical Decisions, Jordan.
Death Caused by Acute Formaldehyde Poisoning during Haemodialysis Treatment in Hospital
Vincent K. K. Mok*, David T. W. Chan
Government Laboratory, Homantin Government Offices, 88, Chung Hau St., Homantin, Kowloon, Hong Kong
Formalin, the aqueous solution of formaldehyde, was used to disinfect the water purification system and the circulation piping system of the Haemodialysis Unit (HU) and the Intensive Care Unit (ICU) in a local hospital. Formalin, at approximately 4% for disinfection residing in the piping of the ICU, was accidentally introduced into the circulation piping system and delivered to the HU where six patients were receiving treatment. Formalin quickly passed into the blood stream of the patients through the dialysis membranes in the dialysis machines.
Three patients subsequently died while another three were seriously injured. Water samples collected at the scene and post-mortem specimens including blood, urine and vitreous humor of the three deceased were sent to the Laboratory for toxicological examination. The blood specimens were examined for formaldehyde and its metabolite, formic acid.
Formaldehyde and proprionaldehyde (the internal standard) in blood were extracted by hexane:dichloromethane (70:30) after derivatision with dinitrophenylhydrazine. The extracts were analysed by gas chromatography with mass selective detection.
Formic acid and propionic acid (the internal standard) were derivatised with methanol in acidic medium and analysed as their corresponding methyl esters by head-space gas chromatography
with flame ionisation detection.
Post-mortem blood formaldehyde levels of the three deceased were found to be 1.3, 1.5 and 3.7 µg/ml while the corresponding formic acid levels were found to be 130, 100 and 110 µg/ml. Formaldehyde was detected in the water samples collected from different sites at the scene at levels ranging from a few µg/ml to 44,000 µg/ml.
The case highlights the importance of adhering strictly to the disinfection procedure by the hospital staff while performing disinfection for the water purification system and the circulation piping system. It also reveals that an effective residual formaldehyde testing method is essential to prevent accidental exposure of patients receiving haemodialysis treatment to water contaminated with formaldehyde.
Keywords: Formaldehyde, Haemodialysis, Disinfection.