A: Prepare a test solution in water containing 10 mg of paromomycin per mL. Apply 25 µL of this solution and 25 µL of a Standard solution of USP Paromomycin Sulfate RS containing 10 mg of paromomycin per mL to a suitable thin-layer chromatographic plate (see Chromatography 621) 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 (4 in 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 10 minutes. Heat the plate at 105 for 1 hour, allow to cool, and spray with a solution of ninhydrin in butanol (1 in 100). Heat the plate at 105 for 5 minutes: paromomycin appears as a red spot, and the RF value 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 191.

Test solution: 50 mg per mL, in water.