Abstract A highly sensitive gas chromatographic–mass spectrometric method for the determination of etodolic acid, as methyl ester, in plasma was developed. The feasibility and specificity of the method was ascertained monitoring the concentration levels in plasma samples collected from 12 male healthy volunteers given epicutaneously 5 g of 10% etodolac gel formulation.
The study was performed with 14C-tiropramide hydrochloride, i.e. O-(2-diethylamino-ethyl)-N-benzoyl-[DL-(U-14C)tyrosyl]-dipropylamide+ ++ hydrochloride, with a specific activity of 466.16 microCi/mmol. For the study of pulmonary, urinary and fecal excretion the substance was administered in single intravenous (i.v.) doses of 4 mg/kg to 4 rats (2 males and 2 females) and in single peroral (p.o.) doses of 10 mg/kg to other 4 rats (2 males and 2 females). For the study of biliary excretion 4 mg/kg of 14C-tiropramide hydrochloride were administered in single i.v. doses to 4 rats (2 males and 2 females) anesthetized with urethane and the bile was collected from the choledocus in the 8 h following administration. The radioactivity in the expired CO2, urine feces and bile was measured by scintillometry. The radioactive substances were extracted, separated by TLC and identified by comparison of their Rf values with those of putative metabolites with known chemical structure. The following results were obtained. Radioactivity in the expired CO2: No radioactivity was found, either after i.v. or p.o. administration. Radioactivity in urine: In the 48 h after administration 37% of the i.v. administered radioactivity and 31% of the p.o. administered radioactivity was recovered in the urine. Six basic substances could be identified. In order of decreasing abundance these were CR 1166, CR 1098, tiropramide, CR 1034, CR 1919 and CR 1938. Radioactivity in feces: In the 120 h after administration 60% of the i.v. administered radioactivity and 56% of the p.o. administered radioactivity was recovered in the feces.(ABSTRACT TRUNCATED AT 250 WORDS)
A gas chromatographic/mass spectrometric analytical procedure is described to determine glycols in plasma as cyclic butyl boronate esters. The method, involving a pre-deproteinization step, required only 0.25 ml of plasma and a short time (20 min) to react with the derivatizing agent (butyl boronic acid). The gas chromatographic separation on a CP Sil 8 CB silica capillary column coupled to a mass detector assured a complete identification of the compounds. The analytical recoveries (>95%) with low coefficient of variation (4–11%) assured the feasibility of the method over a concentration range from 5 to 1000 μg ml−1 for each glycol. The lower detection limits, namely 1–5 μg ml−1, confirmed the sensitivity of the method.
To assess the pharmacokinetics of recombinant human LH (rhLH) in monkeys, we measured serum LH levels after single iv injection and after single and repeated doses by the im or sc route. A single iv bolus of 400 IU/kg rhLH or pituitary hLH (phLH) in six cynomolgus monkeys resulted in parallel concentration-time curves. The initial and terminal half-lives of rhLH (0.8 and 11 h) were comparable to those of phLH (0.6 and 10 h). The serum levels of phLH were consistently higher due to the fact that the immunological dose of phLH was higher. Administration of increasing iv doses of rhLH (10, 63, and 400 IU/kg) to six monkeys showed that the pharmacokinetics are linear over this dose range. The total clearance for the two higher doses was 0.03 L/h.kg. Systemic bioavailability was 50% after a single sc injection of 400 IU/kg and 61% after a single im injection of the same dose. The peak concentration (180 IU/L) after im injection was reached after 2.7 h. This was higher and sooner than after sc injection (110 IU/L after 5.3 h). The terminal half-life by both routes was similar to that seen after iv injection (11 h). Daily sc or im administration of 63 IU/kg for 7 days confirmed these findings. There was no accumulation of rhLH. Some monkeys developed antibodies, especially after repeated administration. They were excluded from the analysis. No significant local or systemic adverse events occurred.
Abstract 3‐L‐Pyroglutamyl‐L‐thiazolidine‐4‐carboxylic acid (Pidotimod), a new immunostimulating agent, has been prepared labelled with 14 C and 35 isotopes starting from L‐[U‐ 14 C]‐glutamic acid 5 and L‐[ 35 S]‐cysteine hydrochloride 6 , respectively. In the first synthesis, L‐[U‐ 14 C]‐ 5 is converted into L‐[U‐ 14 C]‐pyroglutamic acid 2 , which was reacted with ethyl L‐thiazolidine‐4‐carboxylate 3 to afford the ester 4 , in turn hydrolyzed to [ 14 C]‐Pidotimod 1 . In the second synthesis, L‐[ 35 S]‐ 6 reacted with formaldehyde to give L‐[ 35 S]‐thiazolidine‐4‐carboxylic acid 7 , which was coupled with the activated ester of pyroglutamic acid, compound 8 , to afford [ 35 S]‐Pidotimod 1 . The total activity of [ 14 C]‐Pidotimod was 1.2 mCi (specific activity 5.52 mCi/mmol) and that of [ 35 S]‐Pidotimod was 1.0 mCi (specific activity 9.43 mCi/mmol).
