Phlebitis of a parental formulation is one of the main concerns for patient compliance. It has two major causes, one is the physical precipitation of the compound in blood stream after administration, and another one is chemically irritation due to the compound chemical entity.
In this study, the phlebitis issue of phase I formulation of compound A was due to its poor solubility. Physical precipitation occurred after formulation intravenous injection. In order to minimize precipitation induced phlebitis, pH combination with cosolvents, surfactants, and Cyclodextrins were used to screen the formulation. L-lactic acid and D-Glucuronic acid are the two counter ions show better solubility of compound A. Both hydroxyl- β-cyclodextrin (HP-β-CD) and sulfobutylether- β-cyclodextrin (SBE- β-CD) have shown further enhancement of the solubility combining with either lactic acid or glucuronic acid. An in vitro dynamic precipitation and an in vivo rabbit ear models have been used to investigate the potential of precipitation and phlebitis of the promising new formulations, there is a correlation between in vitro and in vivo findings. Based on both in vitro and in vivo data, the formulation composed of 40% SBE--β-CD, 50mM Glucuronic acid, and 13mg/ml compounds A has shown significant improvement of phlebitis compared to phase 1 formulation.