ABSTRACT
Spray systems produce similar results to eye-drops in terms of duration of drug action and side effects. Sprays have several advantages over eye-drops:
1. a more uniform spread of drug can be achieved 2. precise instillation requiring less manual dexterity than for eye-drop administration
and is particularly useful for treating patients with unsteady hand movements 3. contamination and eye injury due to eye-drop application are avoided 4. spray delivery causes less reflex lacrimation. 5. Can be used by patients who have difficulty bending their neck back to administer
drops. The only disadvantage is that sprays are more expensive to produce than eye-drops
so they are not widely used; however, several manufacturers have advanced spray systems at a pre-production stage. Prototype devices that force small volumes through a valving system look promising as delivery devices of the future. Recently, it has been demonstrated that one sixth of the conventional dose of pilocarpine hydrochloride delivered in this manner produces an equivalent miosis to the standard dose12.
