Determination of ethanol in human fluids — I. Determination of ethanol in blood

Ethanol pharmacokinetics in neonates and infants

Introduction

Ethanol has been used for years in neonatal and infant liquid medications, yet the pharmacokinetics, pharmacodynamics, and safety of ethanol in this vulnerable population have not been well characterized. The purpose of this review is to raise awareness of ethanol use as an excipient in neonatal and infant medications and to provide insight, based on the available evidence, into clearance rates of ethanol in babies. We also discuss ethanol pharmacokinetics in adults, theoretical pharmacokinetic changes in neonates and infants as it may apply to ethanol disposition, and case reports involving ethanol exposure in neonates and infants.

Materials and methods

This study was a narrative review in which relevant papers were selected using databases and scientific search engines such as PubMed with the key words ethanol, infant, and newborninfant.

Results

It remains unclear what ethanol exposure is safe for neonates and infants. The Food and Drug Administration and American Academy of Pediatrics have both taken action, by either setting limits of ethanol content in over-the-counter medications or by recommending restricted exposure to ethanol-containing pediatric formulations.

Conclusions

Until the short- and long-term health effects of chronic ethanol administration can be further characterized, ethanol-containing medications should be used with caution.

Ethanol Analysis in Postmortem and Human Performance Forensic Toxicology Cases

Ethanol analysis is probably the most common procedure performed in forensic and analytical toxicology laboratories worldwide. Ethanol poisoning is very important in both clinical and forensic investigations. In clinical evaluations, measuring the ethanol concentration is necessary for the timely and appropriate delivery of care to patients who may experience discomfort or life threatening ethanolic overdose or mixed ethanol-drug intoxication. In forensic toxicology investigations, ethanol is routinely measured in both human performance forensic toxicology cases such as drug-facilitated crimes and driving-under-the-influence cases, as well as in postmortem forensic toxicology cases. This review presents information regarding the most commonly analyzed biological specimens used in alcohol analysis including, among others, blood, breath, urine, oral fluid, and vitreous humor. Additionally, it presents the various chemical, biochemical, gas chromatographic, and breath testing techniques commonly employed in ethanol analysis and considers the main advantages and disadvantages of each. Finally, a brief discussion of quality assurance in alcohol analysis is presented.

Blood alcohol testing: comparison of the performance obtained with the different methods used in the Belgian external quality assessment schemes

This study describes the performance of the different methods used for blood alcohol analysis by the Belgian laboratories participating in the external quality assessment scheme. The best performance was achieved by the gas chromatography (GC) and the enzymatic methods. The enzymatic methods are easier to use but more apparatus-dependent, whereas GC methods display higher precision, especially at concentrations near the critical legal limit of 0.5 g/l. The study highlights the need to introduce a methodology other than the chemical oxidation-based method of Casier, the sole legal method for forensic analyses in drinking-driving cases in Belgium. This method with poor intra-laboratory, inter-laboratory and linearity performances has definitely become obsolete. Even though GC clearly appears as the method of choice, mainly due to its higher specificity, the present study also shows the need for practical guidelines to improve the quality of GC alcohol analyses used in Belgium.

Validation of an enzymatic method for the determination of trace levels of ethanol

The validation of an enzymatic method for the determination of trace levels of ethanol is described. The method, which involves the use of alcohol dehydrogenase (ADH) and nicotinamide adenine dinucleotide (NAD+), was validated according to USP 23 requirements. The validation parameters, including linearity and range, accuracy (recovery), precision, ruggedness, limit of detection (LOD), and limit of quantitation (LOQ), were established satisfactorily. The method is specific and selective for ethanol except in the presence of propyl, isopropyl, or butyl alcohol.

Quantifying ethanol by high performance liquid chromatography with precolumn enzymatic conversion and derivatization with fluorimetric detection

We quantified ethanol by measurement of the subsequent increase in acetaldehyde after reaction with alcohol dehydrogenase and nicotinamide adenine dinucleotide (ADH-NAD) with a fluorimetric HPLC method. Ethanol standards ranging from 0.3 to 200 mg/dl were investigated and the limit of quantitation of the fluorimetric HPLC method was found to be 6 mg/dl. The accuracy of the HPLC method was assessed by assaying blood samples containing 6-200 mg/dl of ethanol and comparing its results to those of the ADH-NAD enzymatic method (r2 = 0.993). The coefficients of variation for intraassay (assayed ten times) and interassay (assayed on 7 consecutive days) were 6.7% and 9.3% for blood samples containing 50 mg/dl of ethanol and 4.0% and 17.9% for blood samples containing 200 mg/dl of ethanol. The blood ethanol concentrations of a volunteer after a pulse of 0.3 g/kg of ethanol determined with the described HPLC method were correlated to the results from the ADH-NAD enzymatic method (r2 = 0.986). In conclusion, the fluorimetric HPLC method for measurement of ethanol here described is of potential clinical utility.

Chromatographic methods for blood alcohol determination

This review is focused on the different chromatographic strategies for blood alcohol determination which can be adopted for clinical and/or forensic purposes. Particular attention is paid to gas chromatography and to high-performance liquid chromatography. However, other analytical techniques in common use, such as chemical and enzymic methods, are also briefly presented, together with some, at present unusual or experimental, approaches, such as enzymic reactors and catalytic electrodes, which are suitable for application in column liquid chromatography. Finally, mention is made of the methods for the determination of acetaldehyde, the major ethanol metabolite, and of some proposed markers of chronic alcohol abuse, such as acetaldehyde-protein adducts and carbohydrate-deficient transferrin. In order to give the background of knowledge for the rational choice of an analytical strategy, an updated outline of ethanol metabolism and toxicology is presented, together with basic information for the interpretation of the results. Problems concerning blood sampling and storage are also discussed.

Development of a statistical model for predicting the ethanol content of blood from measurements on saliva or breath samples

Blood, saliva and breath samples from a population of males and females subjected to the intake of preselected amounts of ethanol, whilst in different physical conditions (at rest, after physical exertion, on an empty stomach and after eating), were analysed by automatic methods employing immobilized (blood) or dissolved (saliva) enzymes and a breathanalyser. Treatment of the results obtained enabled the development of a statistical model for prediction of the ethanol concentration in blood at a given time from the ethanol concentration in saliva or breath obtained at a later time.

Enzymatic determination of ethanol in saliva by flow injection analysis

Enzymatic photometric and fluorimetric methods are proposed for the determination of ethanol in saliva with determinative ranges of 2.5-15.0 mug ml(-1) and 1.0-20.0 mug ml(-1) respectively, i.e. covering the legal ranges after 1 : 100 dilution. A comparison between the ethanol content in saliva, breath and blood has been carried out on 12 individuals; the determination in saliva has been shown to be a good option.