[The study of resorcin eyedrops]

Area of Science:

• Ophthalmology
• Pharmaceutical Sciences
• Chemical Stability

Background:

• Resorcin is used in ophthalmic preparations.
• Ensuring the stability and biological tolerance of eye drops is critical for patient safety and therapeutic efficacy.
• Oxidation products can negatively impact the biological tolerance of ophthalmic formulations.

Purpose of the Study:

• To prepare and evaluate resorcin eye drop formulations with various physico-chemical stabilizers.
• To investigate the relationship between the physico-chemical stability of resorcin eye drops and their local biological tolerance in rabbit eyes.
• To identify optimal formulation parameters for stable and well-tolerated resorcin eye drops.

Main Methods:

• Preparation of seven resorcin eye drop formulas incorporating different stabilizers, acid buffer solutions, antioxidants (e.g., sodium pyrosulphite, cysteine), and chelating agents (e.g., EDTA-Na).
• Evaluation of physico-chemical stability of the prepared formulations.
• Assessment of local biological tolerance in rabbit eyes.

Main Results:

• A direct correlation was observed between the physico-chemical stability of resorcin eye drops and their local biological tolerance in rabbit eyes.
• Specific oxidation products were identified as the cause of biological intolerance.
• Formulations maintained at a pH below 5 exhibited enhanced resorcin stability and improved ocular tolerance.

Conclusions:

• The physico-chemical stability of resorcin eye drops is directly linked to their ocular biological tolerance.
• Controlling oxidation and maintaining an acidic pH (below 5) are key strategies for developing stable and safe resorcin eye drop formulations.
• These findings provide valuable insights for the development of improved ophthalmic preparations containing resorcin.