CGS 20625

Determination of a potential anxiolytic drug (CGS 20625) in human plasma by high-performance liquid chromatography.[Pubmed:1686029]

J Chromatogr. 1991 Aug 23;568(2):487-93.

An analytical method employing reversed-phase high-performance liquid chromatography is described for the determination of a potential anxiolytic agent in human plasma. This experimental drug candidate has potent and selective affinity for the central benzodiazepine receptor complex. The compound and internal standard are extracted from buffered plasma (pH 9.0) into ethyl acetate. The solvent is evaporated and the residue is reconstituted in chromatographic mobile phase. Separation is achieved on a 5-microns phenyl column with ultraviolet absorbance detection of the drug and internal standard at 270 nm. Recovery and reproducibility assessments indicate good accuracy (overall relative recovery of 101%) and precision (coefficients of variation from 2.0 to 11%) over the concentration range 10-1000 ng/ml. The limit of quantification for the method is 10 ng/ml. The method is suitable for pharmacokinetic analysis following the administration of 80 mg of drug to normal volunteers.

Oral absorption of CGS-20625, an insoluble drug, in dogs and man.[Pubmed:8576841]

J Pharmacokinet Biopharm. 1995 Feb;23(1):11-23.

Oral bioavailability of highly water-insoluble drugs is often quite limited and variable, requiring the development of improved formulations. Animal models are an essential aspect of the design and testing of such formulations designed to improve absorption in man. The present report compares the absorption of CGS-20625, an insoluble drug, in dog and man after oral administration of the drug as a powder, a solid dispersion capsule, and after gastric and duodenal administration in PEG 400 solution. CGS-20625 powder (20 mg) given orally exhibited slow, delayed absorption in both dog and man, with a Cmax of 0.26 +/- 0.07 microgram/ml at Tmax of 3 hr in dog, and 0.01 +/- 0.004 microgram/ml at 2 hr in man. Administration of CGS-20625 in PEG 400 solution improved absorption in dog and man, with a Cmax of 1.2 +/- 0.10 microgram/ml at Tmax of 0.25 hr in dog, and a Cmax of 0.10 +/- 0.04 microgram/ml at 0.5 hr in man. Tmax after administration of the hard gelatin capsule formulation was 0.9 and 1.0 hr in dog and man, with Cmax of 0.89 +/- 0.16 and 0.052 +/- 0.014 microgram/ml, respectively. Absolute bioavailability of CGS-20625 powder in the dog was 0.67 +/- 0.21, whereas the bioavailabilities of the powder and the capsule relative to the PEG 400 solution were 0.84 and 1.1, respectively, in dog, and 0.41 and 0.85 respectively, in man. No significant benefits of duodenal administration were observed. Plasma levels were approximately 10-fold greater and oral clearance was approximately 5-fold less in the dog than in man. Furthermore, pharmacokinetic data were less variable and relative bioavailability was greater in dogs than in humans. Physiological factors in the gastrointestinal tract or greater first-pass metabolism in man may account for these species differences. The relative rate and extent of CGS-20625 absorption were similar between dog and man, in the order of powder < capsule < PEG 400 solution. In addition, in vivo absorption rates in both species reflect in vitro dissolution differences between the powder and the capsule. These data strongly support the use of the dog as a model for developing improved formulations of CGS-20625. Further investigation of the dog as a model to evaluate insoluble drug absorption is warranted.

CGS 20625, a novel pyrazolopyridine anxiolytic.[Pubmed:2563294]

J Pharmacol Exp Ther. 1989 Jan;248(1):89-96.

CGS 20625 (2-(4-methoxyphenyl)2,3,5,6,7,8,9,10-octa hydrocyclohepta[b]pyrazolo-[3,4-d]pyridin-3-one) is a potent and selective ligand for the central benzodiazepine receptor (IC50 = 1.3 nM), with little or no affinity to several other neurotransmitter receptor binding sites in vitro. CGS 20625 had a gamma-aminobutyric acid ratio of 0.9 and increased t-[35S]butylbicyclophosphorothionate binding by 20% in vitro, a profile indicative of a partial agonist or mixed agonist/antagonist. In vivo, CGS 20625 blocked a pentylenetetrazol discriminative cue with an ED50 = 1.7 mg/kg p.o. The compound selectively increased conflict responding in the Cook-Davidson paradigm with a minimal effective dose of 0.3 mg/kg p.o., as compared with 3.0 mg/kg p.o. for diazepam. At doses as high as 100 mg/kg p.o., CGS 20625 had no effect on variable interval responding, suggesting minimal sedation. Unlike diazepam, CGS 20625 had no effect on rotorod performance at doses up to 100 mg/kg p.o. indicating no overt muscle relaxation, and did not potentiate the action of ethanol in this behavioral paradigm. Also, CGS 20625 had no marked effect on locomotor behavior, did not potentiate hexobarbital sleep time and had no sedative activity at doses up to 300 mg/kg p.o. CGS 20625 was efficacious in preventing pentylenetetrazol-induced seizures (ED50 = 0.7 mg/kg p.o.), had less efficacy with no clear dose-response relationship against picrotoxin-induced seizures and had no effect on either strychnine or electroshock-induced convulsions at doses up to 300 mg/kg p.o.(ABSTRACT TRUNCATED AT 250 WORDS)