Stabilization of Octastatin®, a somatostatin analogue: comparative accelerated stability studies of two formulations for freeze-dried products

Abstract Octastatin ® (vapreotide INN) is a somatostatin analogue being developed in gastro-enterologic, neuroendocrine and oncologic applications. The pharmaceutical form is a freeze-dried preparation for parenteral injection use. This study was intended to evaluate the stability of the freeze-dried products and to determine the optimally stable formulation. Two types of stabilizing agents (lactose and glutamic acid/sodium glutamate buffer) and three dosage forms (0.5, 1.5, 15 mg of vapreotide base) were investigated. The peptide content and chemical stability of cakes stored at 50 °C and 70% relative humidity were determined by HPLC and the regression analysis parameters calculated. Results indicate that the formulation with glutamate buffer is appropriate for long term storage.