Metabolism, Excretion and Pharmacokinetics of MLN3897, a CCR1 Antagonist, in Humans.

UNLABELLED: MLN3897 is a small molecule antagonist of the C-C chemokine receptor-1. Since preclinical studies showed that the molecule was metabolized into two halves, the metabolism, excretion, and pharmacokinetics of MLN3897 were investigated in humans using MLN3897 14C-radiolabeled either on the chlorophenyl (CP) or the tricyclic (TC) half of MLN3897 after an oral dose. OBJECTIVE: To evaluate the mass balance, metabolism and pharmacokinetics of MLN3897 in two cohorts of six randomized healthy subjects. METHOD: After receiving informed consent, subjects were dosed after an overnight fast of 10-hours followed by at least 4- hours after dosing on day-1. Each cohort received a single 29 mg oral dose of either the CP or the TC as an oral solution in water. Serial blood samples, urine and feces were collected over a 10-day period post-dose. RESULTS: For both radiolabeled moieties, 55-59% of the dose was recovered in feces and 32% recovered in urine. MLN3897 was metabolized extensively in humans, with minor amounts of intact MLN3897 detected in the urine and feces. N-oxidation of the tricyclic moiety (M28) and N-dealkylation of the piperidinyl moiety were the primary metabolic pathways leading to further formation of the carboxylic acid metabolite (M19) and the (4-(4-chlorophenyl)-3,3- dimethylpiperidin-4-ol) metabolite (M40). Oxidative metabolites M11, M19, M28, M44 were present at >10% of the total circulating radioactivity and also at >25% of MLN3897 exposure. Metabolites resulting from the chlorophenyl-labeled moiety (M40) had significantly more systemic exposure compared to the tricyclic-labeled moiety (M19).

Sensitive analytical method for the novel H1-receptor antagonist HSR-609 in human plasma and urine by high-performance liquid chromatography with pre-column fluorescent derivatization.

A simple and sensitive method for quantitation of HSR-609 (I) in human plasma and urine was developed using HPLC with the fluorescence labelling reagent 4-(N,N-dimethylaminosulfonyl)-7-N-piperazino-2,1,3-benzox adi azole (DBD-PZ). Compound I was extracted from human plasma and urine, and derivatized by reaction with DBD-PZ in the presence of Mukaiyama reagent A, an equimolar solution of 2,2'-dipyridyl disulfide (DPDS) and triphenylphosphine (TPP) in acetonitrile. The reaction mixture was cleaned up by liquid liquid extraction following the derivatization. The conjugate was analyzed by ion-pair-HPLC with fluorometric detection. The quantitation limits for I were 0.5 ng/ml in plasma and 5 ng/ml in urine. Using this method, plasma concentration and urinary excretion of I were studied after oral administration of I to human volunteers.