Paromomycin sulfate

Solutions for analysis were filtered through a 0.45 μm Millex Millipore PVDF membrane prior to measurement. Isothermal titration calorimetry (ITC)measurementswere carried out with a Microcal VP-ITC instrument. Solutions of neomycin sulfate, paromomycin sulfate and CMD-PEG were prepared in a phosphate buffer (10 mM, pH 7.0). Prior to measurements all solutions were degassed under vacuum for about 10 min to eliminate any air bubbles. Aliquots of the neomycin sulfate solution (10 μL, 6.0 g/L, 6.6mM, 39.6mM amine) or paromomycin sulfate solution (10μL, 5.65 g/L, 7.92mM, 39.6m Mamine) were injected from a 300 mL continuously stirred (300-rpm) syringe into a solution of CMD-PEG (1.43 mL, 0.75 g/L, 2.61 mM carboxylate) at 25 ℃. Heats of dilution and mixing were determined in control experiments by injecting aliquots (10μL) of each drug solution into the same buffer (1.43mL).Atotal of 28 aliquotswere injected into the sample cell in intervals of 300 s. The calorimetric datawere analyzed and converted to enthalpy change using Microcal ORIGIN 7.0.