11 DESCRIPTION
Hydromorphone Hydrochloride Injection is an opioid agonist, available as an aqueous sterile solution. Each 1 mL of sterile solution contains 1 mg, 2 mg, or 4 mg hydromorphone hydrochloride for use in intravenous, intramuscular and subcutaneous administration. Each 1 mL also contains 5.4 mg sodium lactate and sodium chloride for isotonicity. The chemical name of hydromorphone hydrochloride is 4,5α- epoxy-3-hydroxy-17-methylmorphinan-6-one hydrochloride. The molecular weight is 321.8 and it has the following chemical structure.

Hydromorphone hydrochloride is a white or almost white crystalline powder that is freely soluble in water, very slightly soluble in ethanol (96%), and practically insoluble in methylene chloride.
The solution pH is adjusted with lactic acid or sodium hydroxide to between pH 3.5 and 5.5.