A: Prepare a test solution in water containing 10mg of paromomycin per mL.Apply 25µLof this solution and 25µLof a Standard solution of USP Paromomycin Sulfate RScontaining 10mg of paromomycin per mLto a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel.Allow the spots to dry,place the plate in a developing chamber,and develop the chromatogram in a solvent system consisting of a mixture of freshly prepared ammonium acetate solution (4in 100),n-propyl alcohol,and ammonium hydroxide (30:10:6)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the chamber,mark the solvent front,and allow it to air-dry for 10minutes.Heat the plate at 105for 1hour,allow to cool,and spray with a solution of ninhydrin in butanol (1in 100).Heat the plate at 105for 5minutes:paromomycin appears as a red spot,and the RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.

B: It meets the requirements of the tests for Sulfate á191ñ.

Test solution: 50mg per mL,in water.