SUMMARY
The synthesis of cocrystals is presented as an alternative to improve the properties of active pharmaceutical ingredients, especially those related to solubility and dissolution rate. In this work the dissolution rate of ciprofloxacin, a zwitterionic fluoroquinolone antibiotic, has been compared to its cocrystal with resorcinol. To this end, dissolution rate has been determined at several biorelevant pH values, and also in two simulated gastrointestinal fluids (FeSSIF and FaSSIF). Results show that both, ciprofloxacin and the cocrystal, dissolve more slowly as pH increases (from 2.0 to 7.4), as ionization degree of ciprofloxacin decreases. In addition, dissolution is not enhanced by the components of the gastrointestinal fluids.