Stabilized pharmaceutical formulations comprising antineoplastic compounds

1. A pharmaceutical formulation, comprising:

(a) an antineoplastic compound having a cyclic or non-cyclic hydrazine, triazine, or tetrazine group, or a pharmaceutically acceptable salt thereof; and

(b) a stabilizer, wherein the stabilizer is an antioxidant and/or more susceptible to nucleophilic attack than the antineoplastic compound;

wherein the lyophilized powder contains less than 0.6 wt % of total impurities, based on the total weight of the lyophilized powder, after storage for 3 months at 40° C./75% RH.

2. The pharmaceutical formulation of claim 1 , wherein the pharmaceutical formulation is a lyophilized powder.

3. The pharmaceutical formulation of claim 2 , wherein the lyophilized powder contains less than or equal to 10% of the initial amount of stabilizer added to the formulation, and wherein the stabilizer is selected from sodium metabisulfite, sodium bisulfite and sodium sulfite.

4. The pharmaceutical formulation of claim 1 , wherein the antineoplastic compound is selected from altretamine, dacarbazine, mitozolomide, procarbazine, and temozolomide.

5. The pharmaceutical formulation of claim 4 , wherein the antineoplastic compound is temozolomide.

6. The pharmaceutical formulation of claim 1 , wherein the stabilizer is selected from alpha tocopherol, ascorbic acid, ascorbyl palmitate, butylated hydroxyanisole, butylated hydroxytoluene, hypophosphorus acid, monothioglycerol, potassium metabisulfite, propionic acid, propyl gallate, sodium ascorbate, sodium bisulfite, sodium formaldehyde sulfoxylate, sodium metabisulfite, sodium sulfite, tartaric acid, and combinations thereof.

7. The process of claim 6 , wherein the stabilizer is sodium metabisulfite.