Endogenous formation of 1-propanol and methanol after consumption of alcoholic beverages

INTRODUCTION

In cases of drunk-driving, allegations that alcohol has been consumed after the incident, are proved by analyzing congener alcohols in the blood sample. 1-Propanol, one of the main congener compounds, was tested, whether it is also endogenously formed when a person has consumed alcoholic beverages.

METHODS

Eleven male and 13 female volunteers consumed congener-free vodka (37.5 vol% ethanol, individual doses: 0.15-0.32 l) within one hour. Blood samples were taken up to 10 h and analyzed for ethanol and congener alcohols by headspace gas chromatography-mass spectrometry.

RESULTS

Ethanol concentrations reached in blood a maximum of 0.65-1.23 g/l and decreased by 0.18 g/l/h (median values). Of the congener alcohols analyzed, only methanol and 1-propanol were detected in the plasma samples of all subjects. The endogenous methanol concentration increased from 0.66 mg/l by 0.22 mg/l/h to 2.19 mg/l (medians). 1-Propanol was not detected prior to alcohol consumption. Maximum concentrations of 0.10-0.32 mg/L were measured after 1.0-4.5 h. A plateau of the 1-propanol concentration was observed in the plasma samples of the 18 subjects lasting for 0.5-4.0 h and this alcohol was completely eliminated at ethanol concentrations of 0.17 g/l (median, range 0.03-0.55 g/l).

CONCLUSION

The results of the study confirm the formation of 1-propanol after consumption of 1-propanol-free beverages, which should be taken into account when evaluating its concentration.

Ethanol production by Candida albicans in postmortem human blood samples: Effects of blood glucose level and dilution

We present two cases in which the ethanol concentration in blood samples taken after death continued to increase in the absence of any remarkable increase in n-propanol concentration. Species of bacteria and yeasts, including Candida albicans were isolated from these samples. We then examined whether C. albicans, the most common yeast in the general environment, was able to produce ethanol in human blood stored at room temperature. Ethanol production increased as the glucose concentration increased, indicating that C. albicans produced ethanol from the glucose. Our results also suggested that C. albicans produced ethanol more easily in blood diluted by intravenous infusions that included glucose than in undiluted blood. These findings are useful for the evaluation of postmortem ethanol production in subjects whose blood has been diluted by infusions with glucose. Furthermore, there was no quantitative relationship between the amount of n-propanol detected and the amount of ethanol production: n-propanol appears to be an unreliable index of putrefaction and postmortem ethanol production by C. albicans. It is possible for the blood ethanol level to be high and n-propanol not to be detected, even if the subject has not been drinking alcohol. We reconfirmed the necessity of immediately adding sodium fluoride to samples for ethanol analysis to prevent postmortem ethanol production.

Pharmacokinetics of propranolol after single and multiple dosing with sustained release propranolol or propranolol CR (innopran XL) , a new chronotherapeutic formulation

Blood pressure rises rapidly upon waking and may be responsible, in part, for the increased incidence of myocardial infarction and stroke during the morning hours. Current formulations and dosing of antihypertensive drugs do not provide maximum coverage during this vulnerable period. This study was performed to demonstrate that propranolol CR (Innopran XL), a novel chronotherapeutic formulation of propranolol designed for nighttime dosing, has appropriate pharmacokinetics to provide maximum cardioprotective effect in the morning. Pharmacokinetics of propranolol CR and sustained-release propranolol after single and multiple doses were determined in normal male volunteers in this open-label, 2-period crossover study. The drugs were dosed in the evening and serial blood samples were taken for determination of propranolol concentration the next 24 to 72 hours. After a single 160-mg dose of propranolol CR administered at 10 pm, absorption was delayed by about 4 hours, after which plasma concentration rose steadily, reaching a peak at about 10:00 am. In contrast, after dosing with sustained release propranolol, plasma levels of propranolol began to rise almost immediately, reaching a plateau between 4:00 am and 10:00 am. During multiple dosing, steady-state trough plasma concentrations were achieved after 2 days with either drug. After the final dose, the plasma profiles of both drugs were similar to those observed in the single-dose study. Bioavailability was similar for both formulations of propranolol. Propranolol CR exhibited appropriate pharmacokinetics for a chronotherapeutic approach to the treatment of hypertension.

Evaluating alleged drinking after driving--the hip-flask defence. Part 2. Congener analysis

The second part of this review describes the principles and practice of forensic congener analysis as an alternative way to evaluate claims of drinking alcohol after driving. Congener analysis was developed, perfected and practised in Germany as a way to evaluate hip-flask defences. This kind of defence challenge arises frequently when the drunk driving suspect is not apprehended at the wheel and especially after hit-and-run incidents. Besides ethanol and water, alcoholic beverages contain trace amounts of many other low-molecular substances, known collectively as the congeners, which impart the characteristic smell and taste to the drink. Importantly, the congener profile can be used to identify a particular kind of alcoholic beverage. Forensic congener analysis entails making a qualitative and quantitative analysis of ethanol, methanol, n-propanol and the isomers of butanol in blood and urine from the apprehended driver and comparing the results with the known congener profile of the alcoholic beverage allegedly consumed after driving. Interpreting the results of congener analysis requires knowledge about the absorption, distribution and elimination pattern of the congener alcohols, including their oxidation and conjugation reactions, and any metabolic interactions with ethanol. Complications arise if drinks with widely different congener profiles are consumed or if the same beverage was ingested both before and after driving. Despite these limitations, congener analysis can furnish compelling evidence to challenge or support claims of drinking alcohol after driving.

Concentration of ethanol and other volatile compounds in the blood of acutely poisoned alcoholics

The presence of volatile compounds, such as acetone, acetaldehyde, methanol, ethanol, isopropanol, and n-propanol, in the blood of 169 acutely poisoned alcoholics was determined. The clinical diagnosis of addiction was made on the basis of a patient interview as well as physical, psychological, and psychiatric examination. At the time of the patients' admission to the clinic, the mean concentration of ethanol in blood was 3.14 +/- 1.10 g/l and its elimination rate in the studied group was 0.27 +/- 0.08 g/kg/hr, an elimination rate significantly higher (P <.001) than that of social drinkers, which averages to 0.014 +/- 0.04 g/kg/h. The presence of other volatile compounds in the blood of alcohol-addicted patients is common. The calculated elimination rate constant of methanol was about 0.2 h(-1). This rate seems to indicate that, in heavy drinkers, the elimination of methanol may be relatively fast even if the ethanol concentration is above 1 g/l. The elimination of other volatile compounds can be accelerated by large doses of ethanol, although it is not correlated with actual blood ethanol level. Moreover, in most of the blood samples with a methanol concentration below 10 mg/l, the measured concentration of acetone was below 7 mg/l and that of isopropanol was below 2 mg/l.

ROC analysis of alcoholism markers--100% specificity

A combination of 4 so-called markers of alcoholism, i.e. methanol, acetone + 2-propanol, gamma-glutamyltransferase and carbohydrate deficient transferrin, was investigated in 341 blood samples from alcoholics and non-alcoholics. From the history of alcohol consumption, four defined subgroups were formed: non-alcoholics divided into (A) 33 persons with no ethanol consumption during the past year and (B) 60 persons with daily consumption less than 40 g ethanol. Alcoholics were divided into (C) 177 persons with no ethanol at the time of admission/first blood sampling (withdrawal therapy) and (D) 71 persons with positive ethanol levels on admission/first blood sampling. All markers showed different extents of overlap between the collectives of alcoholics and non-alcoholics. By logistic regression, a formula was developed combining these markers with different mathematical weights. Thus an "Alc-Index" could be calculated for each individual. The ROC curve connecting all individual values gives an ideal form with 100% specificity and nearly 93% sensitivity. The threshold between the collectives of alcoholics and non-alcoholics was defined by the Alc-Index value 1.7. This was associated with no false positives among the non-alcoholics while nearly 93% of the alcoholics exceeded this index. The ROC-based calculation of the Alc-Index thus seems to be the most effective method for the diagnosis of alcoholism.

Biotransformation of sevoflurane

Several characteristics of sevoflurane biotransformation are apparent from the preceding investigations. Metabolism is rapid, with fluoride and HFIP appearing in plasma within minutes after the start of sevoflurane administration (38-40,51). Peak plasma fluoride concentrations generally occur within approximately 1 h after the termination of sevoflurane administration in most patients, regardless of the dose or duration of exposure (ranging from 0.35-9.5 MAC-h) (39,48). Peak plasma inorganic fluoride concentrations are proportional to sevoflurane dose, measured in MAC-h (42-44). Inorganic fluoride concentrations decline rapidly after termination of sevoflurane administration, with concentrations well below peak levels by the first postoperative day. HFIP is rapidly conjugated, with more than 85% circulating in plasma as the glucuronide. Plasma HFIP concentrations peak later than fluoride concentrations, but both metabolites are eliminated at similar rates (52). Metabolism of sevoflurane does not contribute to the termination of clinical drug effect (52), unlike more extensively metabolized drugs such as halothane (55). Sevoflurane is metabolized by P-450 2E1, so pathophysiologic factors and drug interactions altering P-450 2E1 activity will also influence sevoflurane metabolism (52). The extent of metabolism of sevoflurane, 2% to 5%, is less than that of all other volatile anesthetics except isoflurane and desflurane. It has been proposed that the ideal anesthetic should resist biotransformation because anesthetic toxicity is related to anesthetic metabolism (67,68). Experience to date suggests that biotransformation of sevoflurane has not been causally related to either hepatic or renal toxicity. Sevoflurane does not result in formation of fluoroacetylated liver neoantigens or other reactive metabolites. Although both sevoflurane and methoxyflurane may produce plasma fluoride concentrations in excess of 50 microM, they have not produced the same nephrotoxic effects. Clearly, anesthetic metabolism and anesthetic toxicity can no longer be considered synonymous. The introduction of sevoflurane into clinical practice will hopefully stimulate new investigations into biochemical mechanisms of anesthetic toxicity and continued clinical investigations regarding the relationship between anesthetic metabolism and organ toxicity.

Reliability of blood alcohol determinations at clinical chemistry laboratories in Sweden

Known concentrations of ethanol, methanol, isopropanol and its metabolite acetone were added to plasma or whole blood and aliquots of each specimen were sent to clinical chemistry laboratories in Sweden as a declared collaborative study. All participants used gas-liquid chromatography (GC) for quantitative determination of ethanol and other low molecular weight volatiles. The mean within laboratory precision for analysis of ethanol, expressed as coefficient of variation (CV), was 4.7% (range 0-15%). The corresponding between-laboratory CV spanned from 8.0 to 19.4% for 23 control specimens analysed between 1987 and 1992. The mean concentration of ethanol reported was not significantly different from the target value assigned. Between 0 and 3 laboratories reported deviant results (Z-score > 1.96) for each of the control specimens. One laboratory reported the presence of methanol instead of ethanol and three laboratories saw traces of acetone instead of the actual concentration present. One laboratory failed to report that methanol was present and another failed to report the presence of isopropanol. The between-laboratory CV ranged between 9.4 and 30.3% for analysis of methanol in 8 control specimens. The larger variability between laboratories compared with within laboratories probably reflects the different calibration procedures used, such as the preparation and source of the alcohol standards.

Relationship of inspired anesthetic concentration to plasma concentration and urinary excretion of sevoflurane metabolites in rats

In patients, plasma concentrations of sevoflurane metabolites may be independent of inspired sevoflurane concentration over a defined dose range. In contrast, studies using rabbits have found that plasma concentrations and urinary excretion of fluoride ion are dose-dependent up to 3% inspired sevoflurane. We measured sevoflurane metabolite concentrations in adult male Sprague-Dawley rats and related them to inspired sevoflurane concentrations. When plasma concentrations and urinary excretion of metabolites were measured in vivo, they were dependent on inspired anesthetic concentration at concentrations less than 1.25%, but became less dose-dependent at higher anesthetic concentrations. Sevoflurane metabolism by precision-cut liver slices in vitro became dose-independent at more than 10-30 microM sevoflurane. No evidence of substrate inhibition was observed. These data provide evidence that sevoflurane metabolite concentrations are almost independent of inspired anesthetic concentration over at least part of the clinically used concentration range.

Simultaneous determination of alcohols and ethylene glycol in serum by packed- or capillary-column gas chromatography

We developed a packed-column chromatographic procedure capable of simultaneous quantitation of methanol, ethanol, isopropanol, acetone, and ethylene glycol. This method was then updated to a rapid, sensitive, wide-bore capillary method. The packed-column system uses direct injection of 1 microL of Na2WO4/H2SO4-deproteinized serum onto a 1.8 m x 2 mm (i.d.) column packed with 80/100 HayeSep R. A linear temperature gradient from 90 to 205 degrees C allows complete elution of all components within 20 min; minimum detection limits are 2 mmol/L. The wide-bore capillary method uses 0.1 microL of sample deproteinized by ultrafiltration, injected onto a 30 m x 0.53 mm (i.d.) 3-microns Rtx-200 (Restek) column. Baseline resolution to a minimum detection limit of 0.1 mmol/L of all compounds is achieved in 5 min with a linear temperature gradient from 40 to 250 degrees C and dual internal standards of n-propanol and 1,2-butanediol.

Measurement of serum isopropanol and the acetone metabolite by proton nuclear magnetic resonance: application to pharmacokinetic evaluation in a simulated overdose model

The purpose of this investigation was to 1) compare the performance of proton nuclear magnetic resonance spectroscopy to gas chromatography head-space analysis in the measurement of serum isopropanol and its metabolite, acetone, obtained during a simulated overdose, and 2) compare pharmacokinetic parameters obtained using the two analytical techniques. Three healthy volunteers ingested 0.6 mL/kg of 70% isopropanol and blood samples were obtained at baseline, 0.16, 0.33, 0.66, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0, 12.0, and 24.0 hours post-ingestion. Resulting sera were analyzed by gas chromatography head-space analysis and proton nuclear magnetic resonance spectroscopy for determination of isopropanol and acetone concentrations. A correlation between concentrations quantitated by gas chromatography head-space analysis versus proton nuclear magnetic resonance spectroscopy was determined using linear regression. Pharmacokinetic disposition parameters were determined from serum concentration-time data and compared using analysis of variance. For isopropanol, the linear regression equation which describes the relationship between gas chromatography head-space analysis and proton nuclear magnetic resonance spectroscopy was y = 1.041x - 2.180 (r2 = 0.995, p < 0.0001); for acetone, y = 1.022x - 0.946 (r2 = 0.984, p < 0.0001). Pharmacokinetic disposition parameters derived from the two analytical methods were comparable. Proton nuclear magnetic resonance spectroscopy can be used to rapidly quantitate serum isopropanol and acetone concentrations in the same sample when gas chromatography head-space analysis is unavailable. Also, proton nuclear magnetic resonance spectroscopy can be used to follow serial serum concentrations during an ingestion for the purpose of pharmacokinetic analysis.

Isopropanol interference with breath alcohol analysis: a case report

The presence of interfering substances, particularly acetone, has historically been a concern in the forensic measurement of ethanol in human breath. Although modern infrared instruments employ methods for distinguishing between ethanol and acetone, false-positive interferant results can arise from instrumental or procedural problems. The case described gives the analytical results of an individual arrested for driving while intoxicated and subsequently providing breath samples in two different BAC Verifier Datamaster infrared breath alcohol instruments. The instruments recorded ethanol results ranging from 0.09 to 0.17 g/210 L with corresponding interferant results of 0.02 to 0.06 g/210 L over approximately three hours. Breath and venous blood specimens collected later were analyzed by gas chromatography and revealed in the blood: isopropanol 0.023 g/100 mL, acetone 0.057 g/100 mL and ethanol 0.076g/100 mL. Qualitative analysis of the breath sample by GCMS also showed the presence of all three compounds. This individual had apparently consumed both ethanol and isopropanol with acetone resulting from the metabolism of isopropanol. An important observation is that the breath test instruments detected the interfering substances on each breath sample and yet they did not show tendencies to report false interferences when compared with statewide interferant data.

Severe isopropanolemia without acetonemia or clinical manifestations of isopropanol intoxication

This is the first reported case of severe isopropanolemia in a patient who did not experience associated clinical manifestations and acetonemia. The patient was found lying face down in a hotel lobby but at admission was alert and oriented to place and person. Toxicological analysis of the patient's serum revealed the presence of isopropanol at a concentration of 72 mmol/L. An increased serum osmolal gap (81 mOsm/kg) was also observed. The serum concentration of isopropanol decreased to 9.5 mmol/L 15.5 h after admission with an estimated half-life of elimination of 5-7 h. No serum acetone was detected throughout the patient's hospitalization. The identity of isopropanol was confirmed by gas chromatography/mass spectrometry. The patient remained awake and alert while in the hospital and was discharged 5 days after admission. These unusual findings raise some fundamental questions about the role of isopropanol conversion to acetone in the manifestation of symptoms usually associated with isopropanol intoxication.

High-resolution proton nuclear magnetic resonance spectroscopy in the detection of low molecular weight volatiles

Proton nuclear magnetic resonance spectroscopy (1H MRS) has been used to identify ethanol in vivo and to detect other exogenous low molecular weight volatiles in human serum. 1H MRS was used to detect and quantitate 15 human sera containing various concentrations and combinations of ethanol, isopropanol, acetone, and methanol as previously quantitated by headspace gas chromatography. The 1H MRS method was linear for each alcohol. The lowest detectable alcohol concentration was 15 mg/L (peak height equal to three times the signal-to-noise ratio), and 30 mg/L (+/- 10% relative standard deviation) was the lowest level reproducibly quantitated. Within-run and day-to-day coefficients of variation (CV) ranged from 0.8 to 2.0% and 0.9 to 1.2%, respectively, for methanol; 0.5 to 1.9% and 0.6 to 1.3% for acetone; and 0.5 to 1.6% and 0.3 to 2.2% for isopropanol. In all cases, the lowest CVs for a particular compound were obtained for the highest measured concentration (1500 mg/L), and the highest CVs were observed for the lowest concentration (250 mg/L). The 1H MRS method for detection of these volatiles does not require sample pretreatment and is nondestructive, which allows for further analysis by other methods.

Fatal inhalational isopropyl alcohol poisoning in a neonate

A 37 weeks gestation, 1500 gram male infant with multiple dysmorphic features underwent surgery for gastroschisis several hours after birth. During post-operative mechanical ventilation, 70% isopropyl alcohol was accidentally placed in the humidifier of the ventilator, resulting in an estimated 2 h exposure. While the baby seemed clinically stable, initial neurological examination was confounded by recent sedation and pancuronium paralysis. Initial post-operative hypotension was corrected with fluid administration and remained stable for the remainder of the clinical course. By 2 h post-exposure, he was moving, breathing spontaneously and opening his eyes. Isopropyl alcohol and acetone levels at 1, 6, 10 h post exposure were 31/10, 22/15, 15/20 mmol/L respectively. Isopropyl alcohol elimination t1/2 was 9.6 h. Dialysis or exchange transfusion were considered but due to their high risk and the stable infant condition, it was elected to continue with supportive care only. 12.5 h post-exposure, he suddenly became cyanotic, bradycardic, then asystolic. Resuscitation efforts were unsuccessful. To our knowledge, this is the youngest patient reported to have toxic inhalational exposure to isopropyl alcohol and the first report on isopropyl alcohol pharmacokinetics at this age.

The use of delta osmolality to predict serum isopropanol and acetone concentrations

We investigated whether serum delta osmolality will predict the total serum concentration of isopropanol and acetone metabolite. Three isopropanol ingestions were monitored by delta osmolality determinations followed by quantification of serum isopropanol and acetone concentrations. The delta osmolality was established by routine chemical analysis and standard freezing point depression osmometry. Serum isopropanol and acetone levels were quantified by gas chromatography-head space analysis (GC-HS). Patients were initially suspected of having isopropanol intoxication secondary to an elevated delta osmolality discrepancy (measured - calculated > 10 mOsm). Serum concentrations versus delta osmolality were analyzed by linear regression (correlation coefficient r = 0.713; p < 0.05). The delta osmolality paralleled and decreased relative to the total low molecular weight of volatile concentration in each case. In emergencies, delta osmolality may be a screening test to identify rapidly patients at risk for complications associated with isopropanol ingestion when GC-HS is not available.

Effects of chronic treatment with ethanol on the development of cross-tolerance to other alcohols and pentobarbital

The development of cross-tolerance to various alcohols and pentobarbital was examined in ethanol (EtOH)-treated mice. Chronic EtOH treatment (dosage rising in steps from 3.5-4.5 g/kg i.p. daily during a 23-day period) produced tolerance to its hypnotic effect. Such tolerance was seen as a reduction in the duration of loss of righting reflex (LRR), as well as higher blood EtOH levels at the offset of LRR, in EtOH-treated mice as compared to saline-treated controls. Cross-tolerance was shown by shifts in dose-response curves for the LRR induced by n-propanol and t-butanol. Such treatment, however, did not confer functional cross-tolerance to n-butanol and pentobarbital. Because n-butanol and pentobarbital are more lipid-soluble, whereas EtOH, n-propanol and t-butanol have low degrees of lipid solubility, the development of cross-tolerance among these sedative-hypnotic drugs might be related to their relative degrees of lipid solubility.

Acute isopropanol ingestion: pharmacokinetic parameters in the infant

We describe a case of isopropanol intoxication in a 2-month-old infant. The source of isopropanol and both the route and time of ingestion could be clearly identified. Serial measurements of isopropanol and acetone provided data for calculating their respective elimination half-lives. Isopropanol (half-life = 5.8 hr) clearance was similar to values reported for adults; acetone (half-life = 10.8 hr) was eliminated twice as rapidly as in adults.

Serum determinations in toxic isopropanol ingestion

A toxic dose of isopropyl alcohol was ingested by six male mongrel dogs to evaluate the relationship between acetone production and isopropyl degradation. Maximal serum isopropyl levels were achieved approximately 2 to 3 hours after ingestion of 60 mL of 70% isopropyl alcohol. Acetonemia occurred rapidly in the serum (within 15 minutes of ingestion) and continued to rise after isopropanol levels plateaued. The levels of acetone and isopropanol correlated positively throughout the study model with an r of .54 (P less than .001). It is concluded that there is a positive relationship between acetone production and isopropyl metabolism in the setting of a toxic ingestion of isopropanol. Acetone's persistence as a serum marker may be beneficial in identifying isopropyl hours after a suspected ingestion.

Reduced blood clearance and increased urinary excretion of N-nitrosodimethylamine in patas monkeys exposed to ethanol or isopropyl alcohol

Low concentrations of N-nitrosodimethylamine are metabolized in rodent and human liver by cytochrome P450IIE1, an activity competitively inhibitable by ethanol. In rodents coadministration of ethanol with N-nitrosodimethylamine results in increased tumorigenicity in extrahepatic organs, probably as a result of reduced hepatic clearance. To test this concept in a primate, the effects of ethanol cotreatment on the pharmacokinetics of N-nitrosodimethylamine were measured in male patas monkeys. Ethanol, 1.2 g/kg given p.o. before i.v. N-nitrosodimethylamine (1 mg/kg) or concurrently with an intragastric dose resulted in a 10-50-fold increase in the area under the blood concentration versus time curves and a 4-13-fold increase in mean residence times for N-nitrosodimethylamine. Isopropyl alcohol, 3.2 g/kg 24 h before N-nitrosodimethylamine, also increased these parameters 7-10-fold; this effect was associated with persistence of isopropyl alcohol and its metabolic product acetone, both IIE1 inhibitors, in the blood. While no N-nitrosodimethylamine was detected in expired air, trace amounts were found in urine. Ethanol and isopropyl alcohol pretreatment increased the maximum urinary N-nitrosodimethylamine concentration 15-50-fold and the percentage of the dose excreted in the urine by 100-800-fold. Thus ethanol and isopropyl alcohol greatly increase systemic exposure of extrahepatic organs to N-nitrosodimethylamine in a primate.

Alcoholism detection markers in blood samples of road users

Alcoholics as participants in road traffic are an international problem. In Germany a confiscated driving licence is only given back by the road traffic authorities to suspected alcoholics after a medico-psychological examination. The problem is: "How can alcoholics be detected among drunken road users." Traffic authorities use as a marker of alcoholism only the height of the blood alcohol concentration. The limit is a level of 1.6 g alcohol per kg blood, in some regions a level of 2.0 g/kg. Our studies show that the blood alcohol level is a very weak marker for alcoholism. Better markers are beside the GGT the alcohols methanol and isopropanol. They can be detected by congener alcohol analysis. Their concentrations are significant elevated by long-lasting drinking like it is typical for alcoholics.

Volatile compounds detected in blood of drunk drivers by headspace/capillary gas chromatography/ion trap mass spectrometry

As shown by others, ethanol and methanol appear in the breath of normals, and endogenous methanol becomes detectable also in the blood after intake of ethanol. In this study I have investigated whether low-molecular-weight volatile organics, other than methanol, arise in the blood of drunk drivers who had imbibed alcoholic beverages. To this end a method for searching for such compounds in the blood is described. It was based on headspace extraction, gas chromatographic separation on a DB-WAX capillary, and ion trap detection in the mass range 29-99 u. Detection limits, as defined by the analyte concentration that gives a signal equal to three times the standard deviation of the baseline noise, were estimated for the different mass numbers used in the substance search. Given the detection limits, presented as mmoles per litre (numbers within parentheses), in every drunk driver's blood with more than 10 mmol l-1 of ethanol between seven and nine different volatile substances were spotted. These were ethanol (0.15), 2-propanone (0.015), ethyl acetate (0.0005), 2-butanone (0.006), methanol (1.5), 2-propanol (0.06), ethanol (0.7), 2-butanol (0.03), and 1-propanol (0.03).

Studies on inhibition and induction of metabolism of ethyl carbamate by acetone and related compounds. Evidence for metabolism by cytochromes P-450

Ethanol and a variety of other compounds previously have been shown to acutely inhibit the metabolism of ethyl carbamate (EC) when given concurrently in mice. On the other hand, ethanol pretreatment (10% in drinking water for the period 48 to 12 hr prior to EC treatment) is known to have the opposite effect and enhance the clearance of EC from blood of mice. In the present work, acetone has been shown to act similarly. Concurrent acetone treatment inhibits the metabolism of EC (11.1 mg/kg po) in male A/JAX mice in a dose-response manner. Blood clearance (Cl) of this po dose of EC from mice following concurrent acetone treatment (50 mg/kg, 0.86 mmol/kg ip) averaged 185 +/- 5.4 (SE) ml hr-1 kg-1 vs. controls of 804 +/- 24.6 ml hr-1 kg-1. Comparing doses that produce equal effects on the blood clearance values of EC, acetone is approximately 50-fold more potent as an inhibitor than ethanol. Pretreatment of mice with acetone (2 g/kg ip) 48 hr and 24 hr before EC administration po increased the clearance of EC approximately 3-fold (CI = 2623 +/- 123 ml hr-1 kg-1). 2-Propanol was found to be at least as potent as inhibitor as acetone, but with a longer duration of inhibition; this longer duration was explained by the longer persistence of acetone in blood from conversion of 2-propanol to acetone.(ABSTRACT TRUNCATED AT 250 WORDS)

Isopropanol ingestion: a report of six episodes with isopropanol and acetone serum concentration time data

The disposition of isopropanol and its major metabolite acetone were observed in six isopropanol ingestion episodes among five patients. Serum admission isopropanol and peak acetone concentrations ranged from 16.5 to 220 mg/dL and 141 to 585 mg/dL respectively. Ingestions ranged from 120 to 300 mL of 70% isopropanol with concomitant ethanol ingestion in two episodes. The isopropanol and acetone apparent half-lives ranged from 2.9 to 16.2 hours (h) and 7.6 to 26.2 h respectively. Two episodes of isopropanol ingestion were observed within a 9 month period in patient one. Isopropanol terminal elimination rate constants were 0.043 and 0.085 per hour (per h) with no marked difference in acetone terminal elimination rate constants (0.025 and 0.033 per h). Discrepancy between the two isopropanol elimination rate constants reflected concomitant ethanol abuse with the first ingestion. Reductions in isopropanol and acetone half-lives were also noted among patients requiring ventilatory support.

Detection of isopropanol in acetonemic patients not exposed to isopropanol

Isopropanol has been identified in five acetonemic patients not exposed to this compound. Serum concentrations ranged up to 297 mg/L for IPA and up to 321 mg/L for acetone. Concentration ratios (isopropanol:acetone) ranged up to 5.12. All five patients had Type I diabetes mellitus and were insulin-dependent. At the time isopropanol was detected each patient was hyperglycemic, and four patients were acidotic. These findings tend to corroborate clinically some earlier autopsy reports that acetone may be converted to isopropanol in physiological conditions in which reduced nicotinamide adenine dinucleotide is elevated. The conversion of acetone to isopropanol in vivo has significant clinical and forensic toxicological implications.

Methoxyflurane enhances allyl alcohol hepatotoxicity in rats. Possible involvement of increased acrolein formation

The effect of methoxyflurane anesthesia on allyl alcohol-induced hepatotoxicity and the metabolism of allyl alcohol was studied in male rats. Hepatotoxicity was assessed by the measurement of serum alanine aminotransferase activity and histopathological examination. Allyl alcohol-induced hepatotoxicity was enhanced when allyl alcohol (32 mg/kg) was administered 4 hr before or up to 8 days after a single 10-min exposure to methoxyflurane vapors. The possibility that methoxyflurane increases alcohol dehydrogenase-dependent oxidation of allyl alcohol to acrolein, the proposed toxic metabolite, was evaluated by measuring the rate of acrolein formation in the presence of allyl alcohol and liver cytosol. The effect of methoxyflurane on alcohol dehydrogenase activity in liver cytosol was also assessed by measuring the rate of NAD+ utilization in the presence of ethyl alcohol or allyl alcohol. Alcohol dehydrogenase activity and rate of acrolein formation were elevated in methoxyflurane-pretreated rats. The results suggest that a modest increase in alcohol dehydrogenase activity and rate of acrolein formation markedly enhances allyl alcohol-induced hepatotoxicity.

The generation of acetonemia/acetonuria following ingestion of a subtoxic dose of isopropyl alcohol

A subtoxic dose of isopropyl alcohol was ingested by three subjects to evaluate the time to and extent of acetone generation and to explore its detection in the urine. Maximal serum isopropyl alcohol concentrations were observed by 30 minutes after ingestion of approximately 1 oz 70% isopropyl alcohol (0.4 mL/kg), but maximal serum acetone concentrations were not recorded until at least four hours postingestion. Urine tested positive (small) for acetone within three hours of ingestion using Acetest urine testing tablets (Ames Labs, Elkhart, IN). It was concluded that acetonemia occurs early after ingestion of isopropyl alcohol and increases as serum isopropyl alcohol concentrations decline. In addition, acetonuria may be qualitatively measured by three hours postingestion with rapid urine screening tests and may remain positive for 24 hours.

Teratogenicity of n-propanol and isopropanol administered at high inhalation concentrations to rats

As part of a teratological evaluation of several alcohols, 10,000, 7000 and 3500 ppm n-propanol or isopropanol were administered by inhalation to groups of 15 pregnant Sprague-Dawley rats for 7 hr/day on gestation days 1-19. The dams were killed on day 20. Half of the foetuses were examined for skeletal defects and the others for visceral defects using the Wilson technique. The highest concentration of n-propanol produced only minimal maternal toxicity, as indicated by observation and by measurement of weight gain and feed and water intake. In contrast, the same concentration of isopropanol produced narcosis in the dams, retarded body-weight gain and reduced the feed intake. At 7000 ppm isopropanol, body-weight gain was retarded but there were no other observable effects in the dams. Following exposure to 10,000 ppm of either alcohol, there were significant (P less than or equal to 0.05) increases in resorptions and decreases in foetal weights compared with the control groups. Foetal weights were also reduced significantly following exposure to 7000 ppm of either alcohol and to 3500 ppm isopropanol. Significantly more litters had malformations following exposure to 10,000 or 7000 ppm of either alcohol, but these effects were seen only in the presence of maternal toxicity. At 3500 ppm, no detectable teratogenic effects were produced by either solvent.

Allyl alcohol liver injury: suppression by ethanol and relation to transient glutathione depletion

Rats metabolized a sublethal gastric dose (0.73 mmol/kg) of allyl alcohol (AIOH) within 10-15 min. Oxidation of AIOH to acrolein was accompanied by an equally rapid, but only transient depletion of hepatic reduced glutathione (GSH). GSH was restored to levels above normal within 5 hrs. Simultaneously, AIOH provoked marked elevation of alanine aminotransferase, gamma-glutamyl transpeptidase, and glutamate dehydrogenase activities in plasma and formation of lesions mainly in the periportal regions of the liver. Inhibition of alcohol dehydrogenase by 4-methyl pyrazole completely counteracted these effects. On the other hand, attempts to potentiate the toxicity of acrolein by the aldehyde dehydrogenase inhibitor cyanamide enhanced only the release of alanine aminotransferase. Co-administration of ethanol (3 g/kg) inhibited the rate of AIOH oxidation by more than 90%. Although with ethanol GSH remained depleted for several hours, the release of enzymes was markedly suppressed and the histologic changes completely prevented. These results indicate that the rapid rate of acrolein formation, rather than persistently lowered GSH content, is crucial in the hepatotoxicity of AIOH. They also suggest, that oxidation of acrolein via aldehyde dehydrogenase does not represent a major pathway for its detoxication in vivo.

Intracellular generation of electronically excited states. Polymorphonuclear leukocytes challenged with a precursor of triplet acetone

When the enol of isobutanal is added to polymorphonuclear cells, it undergoes an intracellular, myeloperoxidase-catalyzed aerobic oxidation with the formation of triplet acetone. The latter induces considerable damage if the enol concentration exceeds 2 mM. Cells which do not have myeloperoxidase are not damaged.

The organization of a 24-hour blood alcohols (volatiles) screening service in a hospital laboratory

We describe the organization that evolved in the Clinical Biochemistry Department of a tertiary-care hospital for handling blood (serum) alcohol (volatiles) determinations. We use a microprocessor-controlled capillary gas chromatography system which will detect and quantitate methanol, ethanol, isopropanol and acetone. Minimal operator intervention is required, allowing operation of the system 24 hours each day, thus permitting timely detection of these volatiles. A Specimen Trace Card has been devised to document continuity of sample handling from the time of blood collection until completion of the analysis. This has proved of value when laboratory records are used for legal purposes.

Pharmacokinetic analysis of a case of isopropanol intoxication

A comatose 46-year-old woman, admitted to the emergency room, had isopropanol and acetone concentrations of 2000 and 120 mg/L, respectively, in her serum. She had no known history of acute isopropanol intoxication and was otherwise physically healthy. Pharmacokinetic analysis showed that the elimination of both isopropanol and its major metabolite acetone obeyed apparent first-order kinetics with half-lives of 6.4 and 22.4 h, respectively. These data contrast with the commonly held view that isopropanol is slowly metabolized. Concentrations of these analytes in cerebrospinal fluid 6 h after admission were similar to those in serum. This is the first report of the pharmacokinetics of both agents in a nonalcoholic person, and it gives the first data on concentrations of these substances in cerebrospinal fluid.

Inhalation of isopropanol: induction of activating and deactivating enzymes in rat kidney and liver. Increased microsomal metabolism of n-hexane

Rats were exposed to isopropanol by inhalation of 200,2000 and 8000 ppm for 2 weeks with a daily exposure of 6 h. A pilot group exposed to 8000 ppm was given a recovery period of 4 weeks. Kidney and liver microsomal metabolism of n-hexane was investigated in vitro concomitant with activities of cytochrome P-450 and GSH enzymes and blood concentration of isopropanol and its metabolite acetone. A dose dependent increase was observed in the formation of all metabolites of n-hexane in both organs. Of special interest was the 9%, 80% and 198% increase of the preneurotoxic metabolite 2-hexanol in kidney microsomes. Cytochrome P-450 was increased 14%, 40% and 43% in kidney after 200, 2000 and 8000 ppm, respectively, and 10% and 19% in liver at 2000 and 8000 ppm. The activity of glutathione S-transferase was unaffected in kidney but elevated in liver, while GSH levels were elevated in both organs. The elevated level of kidney cytochrome P-450 did not return to normal during the 4-week-recovery period in contrast to liver cytochrome P-450. It is thus indicated that cytochrome P-450 and associated microsomal enzymes are more easily inducible and the changes more persistent in kidney than in liver. Our observations suggest that cytochrome P-450-mediated metabolic activation of n-hexane in the kidneys may have toxicological relevance in addition to liver metabolism, and that coexposure to isopropanol and n-hexane may represent an enhancement of the health hazard from n-hexane, possibly due to the isopropanol metabolite acetone.

Differing effects of short-chain alcohols on body temperature and coordinated muscular activity in mice

Administration of single doses of ethanol, 1-propanol, 1-butanol or 1-pentanol to mice caused hypothermia and impairment of rotarod performance. Repetitive doses, at 24-72 hr intervals led to development of tolerance to the hypothermic effects of ethanol but not of the other alcohols. No tolerance was seen in the impairment of rotarod performance with repeated doses of any of the alcohols. Ethanol did show an intersession tolerance on rotarod performance; at 20 and 80 min after injection, blood levels were similar, while performance was impaired at 20 but not at 80 min.

Brain membrane disordering after acute in vivo administration of ethanol, isopropanol or t-butanol in rats

Brain synaptosomal membranes were prepared from rats sacrificed 18 hr after a single intragastric dose of water or of ethanol (100 mmol/kg), when blood ethanol had fallen almost to zero. Fluorescence polarization of DPH, and (Na+ + K+)ATPase activity, were studied in these membranes in the presence of 0, 0.175, 0.3 or 0.7 M ethanol in vitro. After in vivo ethanol, basal ATPase activity was slightly increased, membrane fluidity was unchanged, but both measures showed increased sensitivity to the effects of ethanol in vitro. Similar results were found after an equivalent in vivo dose of isopropanol, but not of t-butanol. These findings indicate that the sensitization to in vitro effects of ethanol or isopropanol, after in vivo treatment with these alcohols, is probably not dependent principally on their lipid solubilities.

Metabolism of acetone to isopropyl alcohol in rats and humans

Isopropyl alcohol and acetone have been detected in autopsy blood samples of individuals not previously exposed to these compounds. Since some of these individuals had a history of diabetes mellitus, it has been suggested that in these cases, reduction of acetone to isopropyl alcohol might be a metabolic pathway for its production. This hypothesis was investigated in a study of normal and diabetic rats. Acute administration of acetone resulted in measureable levels of isopropyl alcohol in blood. Metabolism of acetone to isopropyl alcohol was different in normal and diabetic animals. Blood levels of isopropanol reached a maximum at the second highest dose in normal rats, but there was a two-phase response in diabetic rats. In a second series of experiments, acetone was administered on alternate days for a week. In spite of this chronic administration (and persistence of high blood acetone), there was no enhancement of acetone metabolism to isopropyl alcohol. These experiments indicate that high levels of blood acetone could result in transformation to isopropyl alcohol.

Quantitative determination of 3-nitropropionic acid and 3-nitropropanol in plasma by HPLC

The separation and determination of 3-nitropropanol (NPOH) and 3-nitropropionic acid (NPA) by reverse-phase high-pressure liquid chromatography (HPLC) is described. The system consists of a Micropak MCH-5 column eluted isocratically with 0.15% orthophosphoric acid (pH 2.0). This technique permits the simultaneous determination of NPA and NPOH in bovine and ovine plasma.

Rates of allyl alcohol metabolism in periportal and pericentral regions of the liver lobule

Rates of allyl alcohol metabolism in periportal and pericentral regions of the liver lobule were measured to determine whether the zonal toxicity due to allyl alcohol results from its selective metabolism in periportal regions. Infusion of allyl alcohol into perfused livers from fed, phenobarbital-treated rats caused an increase in NADH fluorescence (366 leads to 450 nm) measured with a large-tipped (2-mm) light guide placed on the surface of the liver. A linear increase in NADH fluorescence was observed when 25-150 microM allyl alcohol was infused; however, when allyl alcohol exceeded 200 microM, oxygen uptake by the liver was inhibited 30-40%, and a large increase in NADH fluorescence occurred. Miniature oxygen electrodes were then placed on periportal and pericentral regions of the liver lobule and local rates of oxygen uptake were determined [Matsumura and Thurman, Am. J. Physiol. 244:G656-G659 (1983)]. Allyl alcohol (350 microM) or acrolein (200 microM) inhibited oxygen uptake only in periportal regions. Micro-light guides were placed on periportal and pericentral regions of livers perfused in either the anterograde or retrograde direction. The maximal increase in NADH fluorescence due to allyl alcohol infusion (100 microM) was greater in pericentral than in periportal regions. 4-Methylpyrazole (80 microM), an inhibitor of alcohol dehydrogenase, prevented the fluorescence increase due to allyl alcohol in both regions, indicating that the changes were due entirely to NADH generated from alcohol dehydrogenase-dependent allyl alcohol metabolism. Using the correlation (r = 0.91) between rates of allyl alcohol uptake and the increase in NADH fluorescence established for the whole organ, local rates of allyl alcohol metabolism were 23 and 31 mumoles/g/hr in periportal and pericentral regions, respectively. These results indicate that metabolism of allyl alcohol occurs at slightly greater rates in pericentral than in periportal regions of the liver lobule. Thirty minutes after the i.p. injection of a necrogenic dose of allyl alcohol in vivo, the concentrations of allyl alcohol in the portal vein and vena cava were 1210 and 530 microM, respectively. Thus, both periportal and pericentral regions of the liver lobule were exposed to concentrations of allyl alcohol (e.g., greater than 200 microM) which were metabolized in the perfused liver. Since allyl alcohol is metabolized in both regions of the liver lobule, the hypothesis that the zone-specific hepatotoxicity results from its exclusive metabolism to acrolein in periportal regions seems unlikely.