Evaluation of the ophthalmic product is done by following tests:-

1. Sterility Test

A sterility test is carried out to detect the presence of a viable form of microorganism in the all-injectable preparation of each lot. Sterility is an absolute requirement of all ophthalmic formulations.

There are two general methods for sterility testing:

1) Membrane Filtration: Method ‘A’

2) Direct inoculation method: Method ‘B

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2. Clarity Test

Ophthalmic solutions must be free from foreign particles, and this is generally done by filtration by membrane filter. The filtration process also helps to achieve clarity of the solution.

Particulate Matter: Ophthalmic solutions should be essentially free from particles that can be observed on visual inspection.

Ophthalmic preparations that are suspensions, emulsions, or gels are exempt from this test.

Light obscuration particle count (LOPC) and microscopic particle count (MPC) tests for the determination of particulate matter in ophthalmic solutions.

3. Leaker Test

4. Tonicity/Iso-tonicity

The term isotonic, meaning equal tone. A solution is said to be isotonic when its effective osmole concentration is the same as that of another solution. In biology, the solutions on either side of a cell membrane are isotonic if the concentration of solutes outside the cell is equal to the concentration of solutes inside the cell. In this case the cell neither swells nor shrinks because there is no concentration gradient to induce the diffusion of large amounts of water across the cell membrane.

Eye can tolerate 0.5 to 2% of NaCl [Acceptable [0.7-1.5%]

An amount equivalent to 0.9% sodium chloride (NaCl) is isotonic with lycrimal/tears.

5. Viscosity

The most common viscosity desired in an ophthalmic solution is between 25 and 50 cps.

6. Ocular toxicity & Irritation

done on Albino Rabbits