Int J Pharm Compd. 2004 Nov-Dec;8(6):492-5.
International journal of pharmaceutical compounding
Antoine Al-Achi, Bhavita Parekh
PMID: 23924818
Human insulin, used in the management of diabetes, is commercially available in the form of solutions or suspensions for injection. This study investigated the preparation and characterization of an oral suspension for insulin. The suspension was prepared by adding human insulin to aqueous soy extract and adjusting the pH of the preparation to 4.0. The mean diameters of insulin particles at this pH were measured to be 29.93 and 28.30 micrometers for volume-surface mean and volume-number mean, respectively. After 24 hours of the suspension standing at room temperature, the sedimentation volume reached a constant value of 0.22. The suspension exhibited shear-thinning rheological properties, since its viscosity decreased when the rate of shear was increased. The formulation was stable for about 18 days when stored in the refrigerator (4 deg C). Compared to a simple solution of insulin stored at a similar acidic pH reported in the literature, the stability of insulin in the suspension has improved over 2000-fold.
