There is some study about stability of somatropin stored in plasticsyringes its about for 28 days.
The stability of somatropin stored in twotypes of plastic syringes was studied. Reconstituted somatropin at high(3.33-mg/mL) and low (1.0-mg/mL) concentrations was stored in polypropylene andpropylene-ethylene copolymer syringes at 2-8 degrees C for 28 days. Thecontents of all syringes were analysed immediately and at 7, 14, 21, and 28days by high-performance liquid chromatography for purity, potency, andpreservative (m-cresol) content; pH, physical appearance, clarity, andpreservative effectiveness were analysed at the same times. Glass vials ofsomatropin reconstituted with diluent served as controls. Somatropin did notshow significant losses in purity or potency during the 28-day study.
m-Cresol concentrations decreased inboth types of plastic syrings, more so in the polypropylene syringes, butremained in excess of the minimum required to pass the USP test of preservativeeffectiveness. On average, the contents of the propylene-ethylene copolymersyringes had greater turbidity than the contents of the polypropylene syringesand, after 21 days, had an unacceptable level of turbidity. No visibleparticulates were present except at 28 days in high-concentration samplesstored in propylene-ethylene copolymer syringes. Somatropin 3.33 and 1.0 mg/mLwas stable in polypropylene syringes for up to 28 days and inpropylene-ethylene copolymer syringes for up to 14 days when stored at 2-8degrees C