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Tonicity adjusting agents
235
Ophthalmic DD: Excipients
• Ophthalmic solutions can be made isotonic using tonicity agents such
as sodium chloride, potassium chloride, buffering salts, dextrose,
mannitol and glycerol, as long as they are compatible with the other
ingredients in the formulation.
• Boric acid in a concentration of 1.9% produces the same osmotic
pressure as does 0.9% sodium chloride.
• All of an ophthalmic solution's solutes, including the active and inactive
ingredients, contribute to the osmotic pressure of a solution.
236 118
Salma E. EL-Habashy
