Streptomycin sulphate microspheres: dissolution rate studies and release kinetics. I.

Targeting of drugs by microspheres, nanoparticles and liposomes is intended to increase the selective targeting to specific organs and to reduce their side effects. Streptomycin sulphate, a tuberculostatic antibiotic, is used as the active principle in this study. The aim is to accumulate the loaded microspheres in the lungs. The release of drugs associated with microsphere carriers has been found to be dependent on a number of factors. The aim of the investigation was to study the influence of the extent and nature of cross-linking, the type and the amount of the matrix material on the release characteristics of streptomycin sulphate microspheres. Human serum albumin and gelatin (Type B) were used as two different matrix materials. The crosslinking agents used were 2,3-butanedione and formaldehyde at different concentrations, and variable duration times. The in vitro release of streptomycin sulphate from microspheres is characteristically biphasic, with an initial fast release (the 'burst effect'), followed by a much slower release. Alteration in the characteristics of drug-loaded microspheres result in significant changes in the second (slow) phase of release. The release profiles of the different formulations has been studied and evaluated kinetically.