Formulation in Pharmacy Practice - eMixt

A New Zealand standardised formulation is available Formula and Batch Sheet
This formula uses Ora-Blend/SF or Ora-Plus and Ora-Sweet/SF; 1:1, and has been approved by the Extemporaneous Compounding Pharmacists' Group.

Alternatives are given below.

Diltiazem hydrochloride is soluble in water.  An injectable preparation, 5mg per mL, is available in some countries and could be administered orally.  Formula A is from a published study.  Formula B is a suggested alternative based on stability information.

Formula A1

Diltiazem 12mg per mL
Diltiazem hydrochloride tablets 90mg 16 
*Vehicle to   120  mL
A 1:1 mixture of Ora Sweet® and Ora Plus®, or a 1:1 mixture of Ora Sweet SF® and Ora Plus®, or cherry syrup (cherry syrup concentrate diluted 1:4 with simple syrup).
Expiry:  30 days
Stability:   These preparations are chemically stable for 60 days but microbial testing and stability under in use conditions were not evaluated.
Storage:  Protect from light.
Shake well before use

  1. The final pH of the formulations investigated by Allen and Ericksen was in the range 3.5 - 4.2.1
  2. Sulieman et al2 investigated the stability of 1mg per mL solutions containing one of the following sugars; dextrose 0.28M, fructose 0.28M, sorbitol 0.28M or 0.56M, sucrose 0.28M.
    Diltiazem potency was maintained for at least 50 days at 25°C.  The initial pH of the solutions ranged from 4.3 - 6.3.

Formula B

Diltiazem Oral Liquid
Diltiazem hydrochloride tablets qs 
Glycerol 40  mL
Syrup 10  mL
Parabens 0.1  %
*Citric acid qs 
Water to   100  mL
*If possible check the final pH.  If the pH is greater than 6 add a small amount of citric acid (50 - 100mg) to bring the final pH approximately in the range 4 - 6.
Expiry:  30 days
Storage:  Refrigerate.  Protect from light (amber container).
Shake well before use

  1. Allen L. V., Erickson M. A.  Stability of baclofen, captopril, diltiazem hydrochloride, dipyridamole, and flecainide acetate in extemporaneously compounded oral liquids.  Am J Health-Syst Pharm, 1996; 53 (Sep15); 2179-2184.
  2. Sulieman MS, Najib NM, Abdelhameed ME.  Stability of diltiazem hydrochloride in aqueous sugar solutions.
    J Clin Pharm Ther 1988; 13: 417-22.

Formulation in Pharmacy Practice
Page Updated August 2011