Application of salt engineering to reduce/mask bitter taste of clindamycin

Palatability of a formulation is one of the primary requirements for therapeutic compliance in children. Clindamycin (CLN) often prescribed to children to treat various infections. However, it has a bitter taste and bad smell. The focus of the present investigation was to develop salt of CLN with a commonly used sweetener such as cyclamic acid (CYA) to improve the palatability. The salt forms were prepared by solubilization crystallization method and characterized by Fourier transformed infrared (FTIR), Near infrared (NIR), Raman, X-ray powder diffraction, scanning electron microscopy, solubility, dissolution, and solid-state physical and chemical stability at 25 °C/60% RH and 40 °C/75% RH for 1 month and 60 °C for 2 weeks. Spectroscopic and diffraction data indicated the formation of a new solid phase, which was different from hydrochloride salt of CLN. Shape of crystal was rectangular prism. Stoichiometric ratio between CLN and CYA in the new salt CLN-CYA was 1:1 and its melting point was 85.6 °C. There was a 2.4-fold reduction in solubility of CLN-CYA at pH 4 compared with CLN-HCl. Moreover, the dissolution rate and extent were similar between the two salts and meeting USP requirement of 85% dissolution in 30 min. Salt was physically and chemically stable at 60 °C, 25 °C/60% RH, and 40 °C/75% RH conditions but hygroscopic at high humidity condition. In conclusion, new salt will provide a new avenue for the development of a palatable formulation of CLN.