COMPARISON OF L-CARNITINE PHARMACOKINETICS WITH AND WITHOUT BASE-LINECORRECTION FOLLOWING ADMINISTRATION OF SINGLE 20-MG KG INTRAVENOUS DOSE/

L-Carnitine, a naturally occurring compound, is indicated in the treat ment of primary systemic carnitine deficiency. To assess the differenc es in pharmacokinetic parameters calculated from data corrected for ba seline versus those from ''uncorrected'' data, compartmental fitting w as carried out for baseline corrected and original plasma concentratio n data obtained following a single intravenous (iv) dose of 20 mg/kg. For free L-carnitine, mean volumes of distribution at steady state (Vd (ss)) of the central Compartment were similar using either approach (9 .86 versus 11.2 L), However, Vd(ss) (54.0 versus 29.0 L) and apparent elimination half-life (17.4 versus 5.0 h) were significantly different between the two data bases. Similar observations were noted for pharm acokinetic parameters based on plasma concentrations of total L-carnit ine. Although the pharmacokinetic parameters obtained after baseline c orrection may represent the kinetics of a bolus dose, the pharmacokine tic parameters from uncorrected plasma data probably represent the cli nical settings for patients. Baseline correction also probably has its greatest value in attempting to determine and/or define the biologica l half-life and Vd(ss) for the ''exogenously'' administered dose and u ncorrected data best describes the pharmacokinetics of composite endog enous and exogenous L-carnitine levels.