A sensitive high-performance liquid chromatographic assay for melphalan and its hydrolysis products in blood and plasma

Abstract

A sensitive high-performance liquid chromatographic assay has been developed for the measurement of the alkylating cytostatic drug melphalan (4-[bis(2-chloroethyl)amino]-L-phenyl-alanine, or L-phenylalanine-mustard, L-PAM) and its two hydrolysis products, monohydroxy melphalan (MOH) and dihydroxy melphalan (DOH). A reversed-phase phenyl column and a mobile phase consisting of acetonitrile/citrate buffer made possible an isocratic separation and quantification. N,N-[bis(2-hydroxy-ethyl)]toluidine has been synthesized as an internal standard structurally related to DOH. A new, accurate "kinetic" calibration procedure enabled us to determine even the concentration of the unstable MOH. The lower limit of quantification was 30 ng/ml for L-PAM and 20 ng/ml for both DOH and MOH with fluorescence detection. The use of this method is illustrated by some pharmacokinetic data in systemic and locoregional melphalan therapy.

Population Pharmacokinetics of Melphalan and Glutathione S-transferase Polymorphisms in Relation to Side Effects

“…31 Melphalan obtained from Sigma (Deisenhofen, Germany) and the internal standard propylparaben (Sigma) were separated on a reversed-phase C 18 column (LiChrospher 100 RP-18, 5 mm particle size; Merck, Darmstadt, Germany) with a corresponding precolumn (LiChroCART 4-4, LiChrospher 100 RP-18 (5 mm); Merck). Concentrations of melphalan in plasma were measured with an isocratic highperformance liquid chromatography with fluorescence detection set to 270 nm (excitation) and 365 nm (emission) based on published methods.…”

“…Concentrations of melphalan in plasma were measured with an isocratic highperformance liquid chromatography with fluorescence detection set to 270 nm (excitation) and 365 nm (emission) based on published methods. 31 Melphalan obtained from Sigma (Deisenhofen, Germany) and the internal standard propylparaben (Sigma) were separated on a reversed-phase C 18 column (LiChrospher 100 RP-18, 5 mm particle size; Merck, Darmstadt, Germany) with a corresponding precolumn (LiChroCART 4-4, LiChrospher 100 RP-18 (5 mm); Merck). The mobile phase was phosphate buffer (0.02 M, pH 4) and methanol (58:42, v/v).…”

The pharmacokinetic advantages of isolated limb perfusion with melphalan for malignant melanoma

“…In reports of ILP it is remarkable that the volume of perfusate, which critically determines the effective concentration of melphalan, has been so neglected. In fact, the volume of prime is often omitted in reports (Storm & Morton, 1985;Schraffordt Keeps et al, 1987;Sugarbaker & McBride, 1976;Mikhail et al, 1984;Rege et al, 1983), even in studies of melphalan pharmacokinetics (Hafstrom et al, 1984;Osterheld et al, 1988).…”

The Biochemistry of Drug Metabolism — An Introduction. Part 3. Reactions of Hydrolysis and Their Enzymes

“…When melphalan was administered to cancer patients, its monohydroxy metabolite, 3.274, and its dihydroxy metabolite, 3.275, were detected in the plasma where their combined AUC (area under the plasma-concentration-time curve) amounted to ca. 30% of the AUC of the drug [179]. In vitro studies have shown that melphalan reacts by the general mechanism discussed above, namely via a first and second aziridinium intermediate.…”