Formulation in Pharmacy Practice  - eMixt

Rifampicin is very slightly soluble in water and slightly soluble in alcohol. Rifampicin syrup made from capsules is potentially very unstable (chemically and pysically).
Commercially manufactured syrups should be used whenever possible. If suspensions are prepared it is important to check the physical characteristics, e.g. ease of redispersion.
The stability of rifampicin in a variety of syrups has been investigated.1

Formula 1

Rifampicin 10mg per mL
Rifampicin capsules 300mg
Syrup to   120  mL
Mix the contents of the capsules with 20mL of the syrup and make up to volume.  Shake well.
Expiry date/stability:  30 days if adequately preserved.

  1. In the study, stability was confirmed in Syrup NF and four other commercially available syrups containing flavours and preservatives.
  2. Shaking the bottle is extremely important in order to ensure dose uniformity.
  3. Simple aqueous suspensions of rifampicin, 10mg per mL, are reported to be unstable2 and are therefore not recommended unless the dose is given immediately.

  1. Krukenburg C.C., Mischler P.G., Massad E.N., Moore L.A., Chandler A.D.  Stability of 1% rifampin suspensions prepared in five syrups.  Am J Hosp Pharm 1986; 43: 2225-8.
  2. Donovan M. Rifampin.  In: Connors K.A., Amidon G.L., Stella V.J.  Chemical Stability of Pharmaceuticals. New York: John Wiley, 1986: 728-32.
Formulation in Pharmacy Practice
Page updated August 2011