Phosphate concentration in ophthalmic corticoid preparations
W Bernauer1, M A Thiel, K M Rentsch
1Department of Ophthalmology, University of Zürich, Zürich, Switzerland. wolfgang.bernauer@hin.ch
Summary
Ophthalmic corticoid preparations vary widely in phosphate concentration, with nearly half exceeding safe physiological levels. Using formulations with normal phosphate levels is crucial to prevent corneal calcification, especially on damaged eye surfaces.
Area of Science:
- Ophthalmology
- Pharmacology
- Biochemistry
Background:
- Topical phosphate-rich preparations can cause corneal calcification on damaged surfaces.
- Understanding phosphate levels in ophthalmic medications is key to preventing ocular calcification.
- This study analyzes phosphate content in ophthalmic corticosteroid formulations.
Purpose of the Study:
- To quantify and assess phosphate concentrations in various ophthalmic corticosteroid preparations.
- To determine the range of phosphate levels in commonly used eye drops.
- To inform clinical practice regarding the safe use of corticosteroids on compromised corneas.
Main Methods:
- Tested 38 commercial ophthalmic corticosteroid preparations.
- Quantified phosphate concentration using the molybdate method.
- Analyzed samples with a Modular P autoanalyzer.
Main Results:
- 47% (18/38) of preparations exceeded physiological phosphate levels (>1.45 mmol/l).
- Phosphate concentrations ranged from <0.1 mmol/l to 62.6 mmol/l.
- Significant variation observed across different corticosteroid types and formulations.
Conclusions:
- Phosphate concentration in corticoid-phosphate formulations is highly variable, influenced by buffer systems.
- Prednisolone acetate preparations demonstrated physiological phosphate levels.
- Recommend using corticosteroid preparations with physiological phosphate concentrations for treating damaged corneas.
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