LC-MS/MS method for determination of geldanamycin derivative GM-AMPL in rat plasma to support preclinical development.

A LC-MS/MS method for determining the concentration of the small molecule Hsp90 inhibitor, GM-AMPL, has been developed and validated in rat plasma to support preclinical development. 17-[2-(morpholine-4-yl)ethyl]amino-17-demethoxygeldanamycin (GM-AMPL) and the internal standard 17-allylamino-17-demethoxygeldanamycin (17-AAG) were sufficiently separated on a Venusil MP C18 column that was eluted with 80% methanol in water at 40°C. Quantification studies were performed with a multiple reaction monitoring (MRM) transition of m/z 657.3→614.3 and 584.3→541.3 for GM-AMPL and IS, respectively, in the negative ion mode. The present method exhibited good linearity (R>0.999) over the concentration range of 2-600ng/mL for GM-AMPL in rat plasma with a lower limit of quantification (LLOQ) of 2ng/mL. The intra-batch and inter-batch assay coefficients of variation (CV) were in range of 1.56-6.84% and 1.62-6.98%, respectively. The plasma samples were extracted with methanol to precipitate protein with extraction recovery in range of 84.09-95.25%. The matrix effect was determined as internal substance (IS) normalized matrix factor of 1.09, 1.18 and 1.05 for samples with three concentration levels of 4, 40 and 400ng/mL, respectively. This validated method was further applied to successfully determine the pharmacokinetic parameters and oral availability of GM-AMPL in Sprague-Dawley rats following intravenous injection and oral administration.

A novel class of geldanamycin derivatives as HCV replication inhibitors targeting on Hsp90: synthesis, structure-activity relationships and anti-HCV activity in GS4.3 replicon cells.

A novel class of geldanamycin (GA) derivatives as hepatitis C virus (HCV) replication inhibitors has been synthesized and their anti-HCV activities were evaluated in GS4.3 HCV replicon cells. Most of the synthesized compounds demonstrated potential activities against HCV in vitro. Substitution with an aliphatic cyclic group (2b) and polar phosphate group (2f) at the 17 position of GA resulted in more potent inhibitory activity. The configurations of the tetrahydrofurfurylamino (THFM) substituents obviously affected their antiviral activities. The 2b with a 2'-(R)-THFM group at the 17 position showed much potent activity and higher selectivity than its 2'-(S) and 2'-(R, S) epimers. In the tested GA derivatives, 2b and 2f show the most potential leading compounds for development of novel anti-HCV agents.

Synthesis and biological evaluation of heat-shock protein 90 inhibitors: geldanamycin derivatives with broad antiviral activities.

BACKGROUND: Previous studies have suggested that geldanamycin (GA) inhibits the replication of several viruses in vitro. Here, we aimed to synthesize and evaluate the antiviral activity of 17-amino-17-demethoxygeldanamycin derivatives. METHODS: A series of 17-substituted and 17-,19-disubstituted GA derivatives were screened for antiviral activities against eight different viral strains, including herpesvirus, hepatitis virus, retrovirus and picornavirus. RESULTS: Most of the tested compounds showed inhibitory activity against the viruses and showed reduced cytotoxicity in vitro as compared with the parent compound GA. In vivo efficacy evaluation results showed that compound 6 noticeably inhibited duckling hepatitis B virus DNA replication in duckling serum after oral administration. Viral rebound did not occur after termination of the treatment. The modified GA derivatives also showed median lethal dose values that were higher than that of the parent GA in mice intraperitoneally treated with the study compounds. CONCLUSIONS: Targeting heat-shock protein 90 could be a new antiviral approach that is not prone to the development of drug resistance. The 17-amino-17-demethoxygeldanamycin derivatives could be novel agents with potential antiviral activity.