The present invention relates to a process of preparing a stable pharmaceutical composition of compounds which are susceptible to hydrolysis comprising a. Addition of required quantity of pharmaceutically acceptable lyophilization excipients optionally in Water for Injection in a formulation vessel; b. Addition of organic solvent to form a appropriate proportion of aqueous and organic solvent; c. Maintaining the temperature of the formulation vessel from the range -5±1°C to - 5±3°C; d. Addition of required quantity of compound susceptible to hydrolysis to form a solution and lyophilizing the solution.