Disposition of [14C]acitretin in humans following oral administration.

The disposition of the antipsoriatic agent, acitretin, was investigated in six healthy human volunteers who each received a single, oral 50 mg dose of [14C]acitretin (50 microCi). plasma, urine, and feces were collected for 240 hr after administration. Mean values of 20.

Multidimensional narrow bore liquid chromatography analysis of Ro 24-0238 in human plasma.

A highly sensitive LC method has been developed and validated for quantitation of Ro 24-0238 in human plasma using Ro 24-2446 as an internal standard. With 1 ml of plasma, the limit of quantitation of the method was 50 pg ml-1 of Ro 24-0238. After solid-phase extraction with C18 reversed-phase cartridges, the samples were reconstituted in an acidic buffer solution; under these conditions, Ro 24-0238 and Ro 24-2446 (IS) were converted to their cationic forms.

Determination of a new antibacterial agent (Ro 23-9424) by multidimensional high-performance liquid chromatography with ultraviolet detection and direct plasma injection.

Analysis of a new antibacterial agent, Ro 23-9424 (I), in plasma has been complicated by the fact that its metabolite, fleroxacin (II), is formed not only in vivo, but also nonenzymatically by the hydrolysis of the ester bond of I. In order to minimize sample preparation time and possible hydrolysis during sample preparation, a high-performance liquid chromatographic procedure was developed which features direct injection of plasma and multidimensional chromatography. The first dimension size-exclusion separation allows plasma proteins to elute with the column void volume.

Determination of Ro 23-7637 in dog plasma by multidimensional ion-exchange-reversed-phase high-performance liquid chromatography with ultraviolet detection.

Ro 23-7637 (I) is a new drug under development for the treatment of metabolic diseases. A high-performance liquid chromatographic-ultraviolet detection (HPLC-UV) analytical procedure for its analysis in dog plasma was developed and is reported here. Following C18 solid-phase extraction, the sample is applied to a strong cation-exchange column in the first dimension.

The metabolism of [14C]rimantadine hydrochloride in rats and dogs.

Metabolism and route of excretion of [14C]rimantadine hydrochloride was studied in male rats after single po (60 mg/kg) and iv doses (15 mg/kg) and in male dogs (5 or 10 mg/kg po and 5 mg/kg iv). Total 14C excretion in urine (po and iv) in both species reached 81-87% of the dose in 96 hr. Rimantadine was excreted in rats free (1.