Is ciprofloxacin acidic or basic?
Your predictions are right; the molecule has more basic character.

The drug itself is practically insoluble in water, because the big organic molecule is near it's isoelectric point at the pure water's pH. However by protonating or deprotonating it and thus making it charged it's solubility is greatly enchanced.

This is also the case with those medical ready-for-use infusions:


  ...CIPRO IV solutions are available as sterile 0.2% ready-for-
  use infusion solutions in 5% Dextrose Injection. CIPRO IV contains lactic acid as a solubilizing agent and hydrochloric acid for pH adjustment. The pH range for the 0.2% ready-for-use infusion solutions is 3.5 to 4.6. 


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