ABSTRACT
Plasma amino acid levels were determined in 40 premature, very low birth weight infants. All blood samples were drawn prior to parenteral nutrition and blood transfusions. Levels were taken from 0 to 90 hours after birth at approximately 12-hour intervals. Dextrose 5% or 10% in water was given intravenously, beginning shortly after birth, as the only caloric source. A total of 69 plasma amino acid determinations were used for statistical analysis of 25 amino acids versus time. Plasma amino acid profiles were separated into several time intervals. An analysis of covariance of the means of these intervals demonstrated a statistical difference (p less than or equal to 0.01 or better) for taurine, lysine, alanine, threonine, valine, tryptophan, cystine and free cysteine/cystine. Thus, plasma amino acid levels should be reviewed in relation to the hours after birth of sampling. By 12 hours after birth, a relatively stable pattern was observed for all amino acids except taurine. Taurine levels continued to decline throughout the observation period. No statistically significant correlations were observed between the plasma amino acid levels and gestational age.
Subject(s)
Amino Acids/blood , Infant, Low Birth Weight/blood , Female , Humans , Infant, Newborn , Infant, Premature , Male , Time FactorsABSTRACT
The stability of bretylium tosylate when mixed with large-volume parenteral (LVP) solutions was assessed over a four-week period, and the compatibility of bretylium tosylate when mixed with eight frequently used drugs was evaluated. Bretylium tosylate admixtures of approximately 1 mg/ml were prepared in both polyvinyl chloride (PVC) bags and glass bottles of 5% dextrose injection, 0.9% sodium chloride injection, and lactated Ringer's injection. The admixtures were examined visually and stored for four weeks at 25 +/- 0.5 degree C under fluorescent light. The concentrations of bretylium tosylate were determined spectrophotometrically at times 0.25, 0.5, 1, 3, 8, 24, and 48 hours and twice weekly thereafter for four weeks. Spectrophotometric assays were confirmed with high-pressure liquid chromatography. Admixtures of bretylium tosylate were prepared with aminophylline, calcium gluconate, digoxin, regular insulin, lidocaine hydrochloride, phenytoin sodium, procainamide hydrochloride, and quinidine gluconate in 5% dextrose injection and 0.9% sodium chloride injection. The admixtures were examined visually for 48 hours. The concentration of bretylium tosylate did not change appreciably during the four-week study period. There were no signs of haze, precipitation, color change, or evolution of gas. There were no apparent differences in stability when comparing the glass with the PVC containers. Bretylium tosylate was also found to be compatible with all the additives tested except phenytoin sodium; a precipitate formed immediately when the latter drug was added to the bretylium tosylate solution. Bretylium tosylate was stable for four weeks in the LVP solutions studied in both glass and PVC containers. The admixtures of bretylium sodium with the other drugs were all visually compatible except those containing phenytoin sodium.
Subject(s)
Bretylium Compounds , Bretylium Tosylate , Drug Incompatibility , Drug Packaging , Drug Stability , Excipients , Glass , Infusions, Parenteral , Polyvinyl Chloride , Solutions , Time FactorsABSTRACT
Stability of dobutamine hydrochloride when mixed with large-volume parenteral solutions was assessed. Dobutamine hydrochloride was added to large-volume solutions of 5% dextrose injection, 0.9% sodium chloride injection, lactated Ringer's injection, and 5% dextrose and 0.45% sodium chloride injection, in both glass and polyvinyl chloride containers; the initial concentration was 1 mg/ml. After 0.25, 1, 3, 8, 24, and 48 hours, the concentration of dobutamine hydrochloride was determined by high-pressure liquid chromatography assay, and each solution was visually examined for evidence of haze, precipitation, color change, or evolution of gas. Concentration of dobutamine hydrochloride in the samples did not exhibit any appreciable change over the 48-hour period, and no HPLC peaks indicating degradation products were noted. Color changes were observed in some of the solutions, but no other visual changes occurred. There were no apparent differences in stability between the admixtures packaged in glass and those in polyvinyl chloride bags. At the concentration studied, dobutamine hydrochloride is stable in the admixtures tested for a minimum of 48 hours.
