GS-441524

Mechanism of action

GS-441524 (GS = Gilead Sciences), is nucleoside analog and molecular prodrug to a pharmacologically active nucleoside triphosphate molecule. Thus, GS-441524 becomes active only after intracellular metabolisation to triphosphate, which is a false substrate for viral RNA dependent RNA polymerase. It is therefore inhibitor, which acts as a termination sequence (terminator) of the viral RNAchain. GS441524 triphosphate by its incorporation interrupts transcription process and the virus can no longer replicate.

Preparation of GS-441524 for injection use

During clinical trials, GS-441524 was dissolved to a concentration of 10 or 15 mg / ml in a solution containing:

  • 5% etanol
  • 30% propylene glycol
  • 45% PEG 400 (polyethylene glycol)
  • 20% water with HCl to adjust the resulting pH to 1,5

The resulting mixture was shaken to dissolve in a sterile 50 ml flask and then placed in an ultrasonic bath for 5-20 minutes until it became completely clear. The drug thus dissolved was then stored in a refrigerator and used within 3-4 weeks.

The above solvent composition was also adopted by all manufacturers of drugs, although, according to the reactions of cats to different brands of drugs, it is apparent that there are some differences in the solvent formula used. Most drugs on the market are manufactured at concentration of 15mg / ml.