Ascorbic acid improves stability and pharmacokinetics of rifampicin in the presence of isoniazid

- Ascorbic acid on dissolution stability and bioavailability of rifampicin in the presence of isoniazid was studied.
- Rifampicin and its metabolite 3-FRSV were analyzed by dual wavelength spectroscopy.
- Ascorbic acid significantly reduced rifampicin degradation and formation of 3-FRSV in acid medium.
- In vitro dissolution stability correlated with in vivo bioavailability of rifampicin.