Formulation in Pharmacy Practice   2nd Edition

Procainamide is freely soluble in water and soluble in alcohol.  The injection can be administered orally.
The pH of all oral solutions must be adjusted to 4 - 6 to prevent procainamide degradation as the amide bonds are susceptible to both acid and base catalysed hydrolysis.
The stability of a number of procainamide oral liquids has been reported.1,2,3

Formula A1

Procainamide hydrochloride 50mg per mL
Procainamide hydrochloride capsules 250mg 24   
*Vehicle to   120  mL
*Choose from:
1:1 mixture of Ora-Sweet and Ora-Plus,
1:1 mixture of Ora-Sweet SF and Ora-Plus, or
Cherry syrup
Expiry:  30 days
Chemically stable for 60 days but microbial testing not performed.
Store in amber, plastic bottles at 5°C or 25°C.  Protect from light.
Shake well before use
  1. There were no significant changes in appearance, odour or pH over the study period.

The stability of procainamide hydrochloride has also been studied in sucrose and maltitol based syrups.2,3
Formula B is adapted from the results of studies performed on syrup based formulations.

Formula B2,3

Procainamide hydrochloride 50mg per mL
Procainamide hydrochloride capsules 500mg 10   
Syrup 70  mL
*Parabens 0.1  %
Cherry flavouring (optional) qs   
Water to   100  mL
*Not required if the syrup contains an antimicrobial preservative.
Expiry:  30 days.
Storage:  Refrigerate or room temperature.  Protect from light.
Shake well before use
  1. 5mg per mL and 100mg per mL liquids are also stable for at least 30 days.3
  2. If the pH is > 6 adjust to pH 4 - 6 with citric acid.
  3. Chemical stability of similar formulations has been demonstrated for up to 15 months.3
    If bulk manufacture with extended expiry dates is planned please refer to the published studies 1,2,3 for more information.

  1. Allen LV, Erickson MA.  Stability of ketoconazole, metazoline, procainamide hydrochloride, and spironolactone in extemporaneously compounded oral liquids.  Am J Health-Syst Pharm 1996; 53: 2073-78.
  2. Alexander KS, Pudipeddi M, Parker GA.  Stability of procainamide hydrochloride syrups compounded from capsules.  Am J Hosp Pharm 1993; 50: 693-8.
  3. Metras JI, Swenson CF, McDermott MP.  Stability of procainamide in an extemporaneously compounded oral liquid.  Am J Hosp Pharm 1992; 49 (7): 1720-4.

Formulation in Pharmacy Practice
2nd Edition