Enhancing physicochemical properties of hydrochlorothiazide with zwitterionic L-proline and 5-fluorocytosine...

Hydrochlorothiazide (HTZ) is a thiazide-type diuretic drug approved by the FDA in 1959 for treatment of hypertension and peripheral edema and has been used since. HTZ exhibits low solubility and low permeability, leading to variable oral bioavailability and limited intestinal drug permeability. For this reason, several attempts to improve HTZ physicochemical properties have been made during the past decades. In the broad frame of molecular crystal engineering, significant efforts and promising results in the quest for more effective solid/dosage forms of HTZ, including studies on polymorphism and cocrystals, are being developed. As part of these efforts, we report here two new cocrystals of HTZ with the zwitterionic l-proline and the prodrug 5-Fluorocytosine. Both cocrystals show improvement in solubility and permeability, suggesting that these new solid forms could be used as new drug candidates to deliver HTZ in the antihypertensive therapy.