- Leak test: Randomly 10 sealed ointment tubes are selected and cleaned with an absorbent cloth. The samples are placed in a horizontal position on a sheet of absorbent blotting paper. This is placed in an oven and maintained at a temperature 60°C for eight hours. All the ointment tubes should pass the test without any leakage.
- Spreadability test to check for particles: Randomly 10 ointment tubes are selected and each ointment tubes is extruded into a flat-bottomed petri dish, melted and allowed to solidify, which is then scanned under a low power microscope. The requirements are met if the total number of particles in all the petri dishes does not exceed fifty and not more than one petri dish contains more than eight particles.
- Drug content: From the weighed quantity of the test ointment, the drug is extracted by suitable method and assayed by suitable analytical techniques to determine the percentage of medicament present in the sample ointment. This is compared with the amount claimed in the label claim.
- Viscosity test: Depending upon the internal standards of the formulator, the viscosity of the formulation is set. The viscosity of the preparation is determined by using “Brookfield viscometer.”
- Microbial limit test: This test is conducted for both raw materials and finished products. The formulation should be free from viable microorganisms. The total aerobic count must not be more than 5000 microorganisms per gram of the ointment. It should not contain more than 100 moulds per gram of ointment. It should also not contain more than 100 yeast per gram and 90 coliforms per gram of ointment.
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