The effect of paraldehyde on intravenous tubing sets.

Paraldehyde is used in the treatment of status epilepticus, alcohol withdrawal, and delirium tremens. Because it is a solvent, concerns have been raised about infusing it through plastic intravenous tubing sets. In a three-phase study, 4% paraldehyde in 5% dextrose solution was analyzed over 24 hours for photodegradation, adsorption to polyvinylchloride- (PVC) and polyethylene- (PE) lined intravenous tubing, and the presence of di(2-ethylhexyl) phthalate (DEHP). Paraldehyde and DEHP samples were quantified by gas chromatography, and DEHP was confirmed by mass spectral analysis. On exposure to light for 24 hours, the concentration of paraldehyde decreased from 100 to 97%. This decrease is statistically significant but clinically insignificant. A 24-hour continuous infusion of paraldehyde through the two types of tubing revealed a decrease in concentration attributable to adsorption of 4% with PE and 13% with PVC tubing at 2 hours. In addition, there was no appreciable leaching of DEHP over 24 hours with either type of tubing. Concerns about paraldehyde's light instability and effects on tubing integrity appear to be unwarranted with commercially available intravenous administration sets.

Delivery of paraldehyde in 5% dextrose and 0.9% sodium chloride injections through polyvinyl chloride i.v. sets and burettes.

The delivery of paraldehyde in 5% dextrose injection and 0.9% sodium chloride injection was studied, and the potential interaction between paraldehyde and plastic i.v. containers and sets was evaluated. Paraldehyde was mixed with either 5% dextrose injection or 0.9% sodium chloride injection in polyvinyl chloride (PVC) bags to form a 4% solution. The bags were fitted with standard i.v. administration sets or burettes with administration sets. The solutions were allowed to drip through the i.v. sets for six hours at room temperature. Samples were taken from the i.v. bag or burette and from the distal end of the i.v. sets at zero, two, four, and six hours. Paraldehyde concentrations were measured using a stability-indicating gas chromatographic method, and the presence of plasticizers was detected by a scanning ultraviolet spectrophotometer. The cumulative amount of paraldehyde delivered at the end of the administration set at six hours was 84% for 5% dextrose solutions in burettes, and 89% or 90% for all other solutions and i.v. sets. An ultraviolet-light-absorbing substance appeared in some of the samples, although a relationship between the presence of this substance and type of solution, time of sampling, or site of sample did not emerge. Particulate matter appeared after two hours in all burettes. Approximately 10%-16% of paraldehyde in 5% dextrose or 0.9% sodium chloride injection is lost when delivered from PVC i.v. bags through standard i.v. administration sets and burettes over a six-hour period.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance characteristics of methods of analysis used for regulatory purposes. I. Drug dosage forms. B. Gas chromatographic methods.

Gas chromatographic methods for the analysis of drug dosage forms consist of a simple extraction, dilution with an internal standard solution, and injection, or, even simpler, dilution with the internal standard solution and injection. These methods were used in 7 collaborative studies of the determination of 12 pharmaceuticals, published in the Journal of the AOAC during 1973-1983. A total of 43 individual materials consisting of various dosage forms were each analyzed, usually in duplicate, by an average of 8 laboratories, with a total of 582 reported determinations. The average within-laboratory coefficient of variation (CVo) was 1.25% and the average among-laboratories coefficient of variation (CVx) was 2.41%, for a CVo/CVx ratio of 0.52, at an average outlier rate of 1.4% of the reported values. The line of best fit for CVx plotted against concentration increases with decreasing concentration, extending from a CVx of approximately 1.8% at 100% concentration to a CVx of approximately 3.2% at 1% concentration. The change in CVx for a 10-fold decrease in concentration is approximately 0.7% CVx, independent of analyte and matrix.