The Effect of Polymer-Drug Ratio on Characteristics, Release and Stability of Ciprofloxacin-Alginate-Kappa Carrageenan Microspheres

Tuberculosis is the top contagious disease in the world caused by the bacterium Mycobacterium tuberculosis. The increasing incidence of drug resistance in Mycobacterium tuberculosis requires alternative therapies, one of which is fluoroquinolones such as ciprofloxacin. Pulmonary delivery systems are used to avoid problems with oral administration, such as first-pass metabolism and targeted delivery. Microsphere formulation is chosen because pulmonary delivery requires a small size (1-5µm) for deposition in the lungs. The purpose of this research is to investigate the influence of the drug-polymer ratio on the characteristics, release, and stability of the microspheres. The polymer used is a combination of sodium alginate and kappa carrageenan. Microspheres were prepared using the ionic gelation technique with aerosolization. The results showed spherical microspheres with smooth surfaces, particle sizes were ranging from 2.25 ± 0.14 µm to 2.83 ± 0.12 µm, moisture contents were below 5%, flow properties were good, yields were ranging from 91.71% ± 5.52 to 93.62% ± 3.97, drug loadings were 2.03% ± 0.12-3.55% ± 0.13, and entrapment effiencies were ranging from 75.27% ± 2.57 to 78.45% ± 1.89. Over a period of 720 minutes, ciprofloxacin release from the microspheres were about 48.20%-91.35%. The release of ciprofloxacin increased with higher ratio of drug-polymer, and the release kinetics followed the Korsmeyer-Peppas model with a release mechanism following Fick's diffusion law. Microspheres remained stable over 28 days. The study suggest that this microspheres system holds significant potential as a drug delivery system to the lungs.