Gentamicin Eye Drops

Aminoglycoside antibacterial.

Gentamicin Eye Drops are a sterile solution of Gentamicin Sulphate in Purified Water.

The eye drops comply with the requirements stated under Eye Preparations and with the following requirements.

A.  Carry out the method for thin-layer chromatography , Appendix III A, using a silica gel precoated plate (Merck silica gel 60 plates are suitable) and as the mobile phase the lower layer obtained by shaking together equal volumes of 13.5m ammonia , chloroform and methanol and allowing to separate. Apply separately to the plate (1) a volume of the eye drops containing the equivalent of 30 µg of gentamicin and (2) 0.1  mg of gentamicin sulphate BPCRS dissolved in a volume of water equal to the volume of the eye drops used. After removal of the plate, allow it to dry in air, spray with ninhydrin solution R1 and heat at 105° for 2  minutes. The three principal spots in the chromatogram obtained with solution (1) correspond to the three principal spots in the chromatogram obtained with solution (2).

B.  In the test for Composition of gentamicin sulphate, the retention times of the four principal peaks in the chromatogram obtained with solution (2) correspond to those of the four principal peaks in the chromatogram obtained with solution (1).

Comply with the test described under Gentamicin Injection, using for solution (2) a solution prepared in the same manner as solution (1) but using 10  ml of a solution prepared by diluting a suitable volume of the eye drops with water to contain the equivalent of 0.045% w/v of gentamicin.

Dilute a volume of the eye drops containing the equivalent of 15  mg of gentamicin to 50  ml with sterile phosphate buffer pH 8.0 and dilute 10  ml of the resulting solution to 50  ml with the same solvent. Carry out the microbiological assay of antibiotics , Appendix XIV A. The precision of the assay is such that the fiducial limits of error are not less than 95% and not more than 105% of the estimated potency.

Calculate the content of gentamicin in the eye drops, taking each 1000  IU found to be equivalent to 1  mg of gentamicin. The upper fiducial limit of error is not less than 90.0% and the lower fiducial limit of error is not more than 120.0% of the stated content.

The quantity of active ingredient is stated in terms of the equivalent amount of gentamicin.