Lawrence A. Kaplan

Simultaneous, high-performance liquid chromatographic analysis of retinol, tocopherols, lycopene, and alpha- and beta-carotene in serum and plasma.

Publisher Summary The analysis of plasma (or serum) for retinol, tocopherols, lycopene, and α- and β-carotene is a complex analytical problem. This chapter discusses the simultaneous high-performance liquid chromatographic (HPLC) analysis of retinol, tocopherols, lycopene, and α- and β-carotene in serum and plasma. The single most critical element in this analysis is proper standardization that begins with an accurate assignment of the concentration of each stock standard to be used. As the tocopherols, lycopene, and carotene are transported in plasma in lipoprotein particles, one major concern of the assay is to be able to extract these compounds from the plasma matrix. As the lipoprotein content of samples will differ, it is possible that the efficiency of extraction of these compounds may also vary. To correct for this, the standard curve is based on internal standards that have extraction and chromatographic properties similar to those of the analyte and on standards that are added to a matrix of pooled serum or plasma. The chromatographic analysis is performed on a 5-μm particle C 18 Biophase ODS column.

Pharmacokinetics of Extended Relief vs Regular Release Tylenol in Simulated Human Overdose

BACKGROUND The purpose of this trial was to compare the pharmacokinetics of the two available acetaminophen dosage forms in simulated human overdose. METHODS Ten healthy volunteers received acetaminophen, 75 mg/kg orally, either as the regular release or extended relief formulation in a random, crossover fashion. Blood samples were analyzed using a TDx assay and a best fit correlation of data points was determined by PCNONLIN. RESULTS The area under the curves for extended relief acetaminophen and regular release acetaminophen were 426 mg h/L and 432 mg h/L, respectively (p = 0.768). The mean half times for extended relief acetaminophen and regular release acetaminophen were 4.02 h and 2.56 h, respectively (p < 0.001). The mean maximum serum acetaminophen concentrations were 62.6 mg/L (414.4 mmol/L:) and 94.3 mg/L (624.3 mmol/L) for extended relief acetaminophen and regular release acetaminophen, respectively (p < 0.001) and the mean time to maximum serum acetaminophen concentrations were 0.87 h and 0.75 h for extended relief acetaminophen and regular release acetaminophen, respectively (p = 0.508). CONCLUSIONS Although the formulations appear to have equal bioavailability, their half-lives and peak concentrations were significantly different. Further study is required to determine whether these differences affect the assessment and management of poisoned patients.

Plasma Catecholamine Levels In Cyclic Antidepressant Overdose

Cyclic antidepressant overdose is a major cause of morbidity and mortality in self-poisoned patients. The major cause of mortality with cyclic antidepressant overdose is cardiotoxicity. We determined plasma catecholamine levels in 41 symptomatic acute overdose patients to identify interactions between QRS duration (a marker for cardiotoxicity) and a presumed hyper-adrenergic state. Using a linear multivariable regression analysis, QRS duration correlated with the presence of cyclic antidepressant, plasma norepinephrine levels, the ratio of norepinephrine to epinephrine level, and pulse rate (p less than 0.001, r2 = 0.42). Commensurate physiologic changes were not found in the presence of elevated catecholamine levels in the cyclic antidepressant overdose group. One possible explanation for the blunted systemic response to the elevated catecholamine levels is adrenergic desensitization. Investigation of serial catecholamine levels during cyclic antidepressant overdose may lead to modification of our current theories of cardiotoxicity and therapy.

Hyperthermia, hypertension, hypertonia, and coma in a massive thioridazine overdose

This report characterizes an atypical presentation of a thioridazine overdose. Clinical manifestations included wide Q.R.S. complex, hyperthermia, hypertension, hypertonia, and coma. Plasma catecholamine levels were markedly elevated. The patient was treated with dantrolene sodium and supportive care. The patients condition improved over time, with questionable response to dantrolene sodium. Supportive care was the mainstay of treatment.