Formulation in Pharmacy Practice   2nd Edition

Tablets are midazolam maleate.  Injection is midazolam hydrochloride.
The aqueous solubility of midazolam hydrochloride is pH dependent.
Solubility increases with decreasing pH and is between 10 - 20mg per mL at pH 3.
Midazolam hydrochloride is stable at pH 3 - 3.6.  The injection (5mg per mL) has a pH of about 3.1

Formula A2

Midazolam 2.5mg per mL
Midazolam hydrochloride injection, 5mg per mL 10  mL
Syrup BP or NF to   20  mL
The final pH should be no more than 4.2, adjustment to a pH of about 3.5 ensures that the drug stays in solution.
Expiry date/Stability:  30 days, if preserved.
Storage:  Refrigerate.  Also stable at room temperature.

  1. Undiluted injection could be administered orally.
  2. If syrup is undesirable in the formulation, dilute the injection with sterile water and adjust the pH to 3 - 3.5 if necessary.
  3. Syrup NF = 85g sucrose in 100mL of water.

  1. McEvoy G.K., ed.  American Hospital Formulary Services, Drug Information. Bethesda, MD: ASHP;
    1993: 1423.
  2. Steedman S.L., Koonce J.R., Wynn J.E., Brahen N.H.  Stability of midazolam hydrochloride in a flavoured dye-free oral solution.  Am J Hosp Pharm 1992; 49: 615-8.

Formulation in Pharmacy Practice
2nd Edition