Formulation in Pharmacy Practice   2nd Edition

METRONIDAZOLE
 
 
Metronidazole has an extremely bitter taste which is very difficult to mask.  It is slightly soluble in water and alcohol.  The commercially available suspension is formulated as the benzoate to improve palatability and this product should be used whenever possible.
Irwin et al1 investigated the stability, palatability and bioavailability of the following formulation.

Formula 1

Metronidazole Suspension 15mg per mL
 
Metronidazole tablets  250mg  
Water mL
Chocolate-Cherry syrup to   100  mL
 
Use the water to wet the tablets and grind to a paste.
 
Expiry:  30 days.  Two months was suggested in the study but in-use conditions were not assessed.
 
Storage:  Refrigerate.
 
Shake well before use
 

 
NOTES
  1. Formula for the Chocolate-Cherry syrup:
    Artificial Wild Cherry Flavour (Fritzsche) 0.6  mL
    Syrup BP 300  mL
    Chocolate Syrup (Nestle Quik) to   500  mL

    The chocolate flavour appears to be the most important factor in masking the taste.  An alternative combination of syrup and chocolate flavour may be acceptable.  The cherry flavour provides a pleasant aroma but is not essential.  Formulations using plain syrup are less palatable.
  2. Ensure that the preparation is adequately preserved.  Most commercially available syrups contain a preservative.
  3. This formulation provided an AUC comparable to that of the equivalent tablet dose.1

REFERENCE
  1. Irwin D, Dupuis LL, Prober CG, Tesoro A.  The acceptability, stability and relative bioavailability of an extemporaneous metronidazole suspension.  Can J Hosp Pharm 1987; 40(2): 42-46.

 
Formulation in Pharmacy Practice
2nd Edition