Comparative study of pharmaceutical properties of some new derivatives of sulfamethoxazole

This paper reports the changes in various physical properties associated with the derivatization of sulfamethoxazole. The properties studied include moisture content, crystallanity, particle size distribution, porosity, flow, compressibility and compactability. It was found that the derivatives, salicylidene-sulfamethoxazole-Zn(II) • H₂O and salicylidene-sulfamethoxazole-Cu(II) • H₂O are crystalline substances. The moisture content was found to be highest in salicylidene-sulfamethoxazole-Zn(II) • H₂O followed by salicylidene-sulfamethoxazole-Cu(II) • H₂O and sulfamethoxazole. The copper complex contained only chemically bonded water, whereas the zinc complex contained both bonded and absorbed water, which affected the strength of the tablets prepared from the three materials accordingly. The particle size decreased on derivatization and complexation with metal ions and the trend was: sulfamethoxazole > salicylidene-sulfamethoxazole-Cu(II) • H₂O > salicylidene-sulfamethoxazole-Zn(II) • H₂O. This trend was represented by better compactability shown by salicylidene-sulfamethoxazole-Cu(II) • H₂O and salicylidene-sulfamethoxazole-Zn(II) • H₂O as compared with sulfamethoxazole. Salicylidene-sulfamethoxazole-Zn(II) • H₂O had the highest porosity followed by salicylidene-sulfamethoxazole-Cu(II) • H₂O, and sulfamethoxazole; this resulted in better compressibility behavior of the complexes. Thus it was observed that salicylidene-sulfamethoxazole-Cu(II) • H₂O and salicylidene-sulfamethoxazole-Zn(II) • H₂O formed stronger compacts. The values of angle of repose and flow rate show better flow properties for salicylidene-sulfamethoxazole-Cu(II) • H₂O as compared with sulfamethoxazole and salicylidene-sulfamethoxazole-Zn(II) • H₂O. It was concluded that derivatization substantially changed the pharmaceutical properties, which have important role to play in formulation of solid dosage form.