[Stability of rifampicin in eyedrops]

The best composition of rifampicin eye-drops for extemporaneous preparation in pharmacies was developed by the authors. The stability of the eye-drops has been studied and storage condition and shelf-life were determined. The preparation, may be stored at minus 12 degrees C for one month and may be subsequently used when stored between 2 and 8 degrees C after the first opening for five days. Rifampicin and its degradation products have been separated by TLC using silicagel layer and chloroform-methanol (42 : 58) eluent. After separation of rifampicin and its degradation products their quantity have been determined by densitometry at 475 wavelength (540 nm for rifampicin quinone). This rifampicin eye-drops have been recommended for inclusion into the 7th Edition of the Official Model Prescriptions (Formulae Normales).