The Formulation Of Stable Adrenaline Eye Drops For Use In The Management Of Glaucoma

Kokwaro GO. The Formulation Of Stable Adrenaline Eye Drops For Use In The Management Of Glaucoma.; 1981.


The different factors affecting the stability of adrenaline
in solution have been examined with a view to producing a
pharmaceutically active eye drop prep~ration of adrenaline. It
was important that such a formulation should be simple enough to

enable preperation using the available facilities in this country_
A preformu1ation screening of antioxidants in the
absence of adrenaline showed that at low/values (around pH 3.0)
sodium sulphite was superior to either sodium metabisu1phite or
ascorbic acid. Accelerated stability studies showed that the
pH of maximum stability for aqueous solutions of adrenaline was
approximately pH 3.7. Accelerated stability tests at this pH

confirmed the superiority of sodium sulphite over a combination
of sodium metabisu1phite and ascorbic acid as antioxidants.
Accelerated stability studies also confirmed the
important role of boric acid in enhancing the stability of adrenaline
in aqueous solutions.
An investigation of four sterilization procedures
showed that the immediate loss of adrenaline was negligible
after either sterilization by filtration or by heating at 980c
for 30 minutes. Higher sterilization temperatures caused
substantial loss of adrenaline and discolouration of the solut
ions ,
For reasons of comfort to the patient on instillation
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into the eye and for clarity of the solution in presence of the
preservative used (Benzalkonium Chloride), a final formulation of
adrenaline eye drops was prepared in borate buffer at pH 5.8,
with sodium sulphite as the antioxidant. Accelerated stability
studies and long term storage studies at ambient temperatures
showed that the final preparation was reasonably stable. Clinical
testing of the preparation on hospitalized glaucoma patients
showed that the preparation compared favourably with commercial
and other preparations used in the management of raised intraocular


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