IMPACT OF STORAGE CONDITIONS ON THE PHYSIOCHEMICAL STABILITY OF IN USE MOXIFLOXACIN EYE DROPS SOLUTION IN ADEN CITY

Abstract

Moxifloxacin hydrochloride (MOX) ophthalmic solution is a critical fourth-generation fluoroquinolone. Moxifloxacin hydrochloride is a synthetic, fourth-generation fluoroquinolone that has become a widely used standard in ophthalmology for treating bacterial conjunctivitis and other ocular infections. The reality is, many patients continue to use these costly drops long after the recommended discard date. The study focused on assessing the physicochemical stability as pH, osmolality, refractive index, and color of three common MOX solutions, the original brand (Vigamox®) and two generic versions (Indian and Pakistani) over a 60-days simulated in-use period under three storage scenarios common in Aden, Yemen, to determine their suitability for continued use and to inform local patient safety guidelines. Three simulated common storage realities: Condition I (ideal, 21.0±1.8 ⁰C): Continuous A/C; Condition II (Common, 29.4±2.9 ⁰C): Intermittent A/C with power outages often exceeding 16 hours daily; and Condition III (Harsh, 33.4±2.3 ⁰C): Non A/C storage, using only a ceiling fan. Samples were checked at baseline, one, two weeks, one month and two months. the simulated patient use done by opening and closing the bottles three times daily for the initial ten days. The results revealed the Stability was largely maintained under Condition I and Condition II (though the Pakistani generic’s pH dipped slightly by day 60 in Condition II). However, under the high-stress Condition III: After two months, both generics showed clear signs of accelerated degradation. Their pH levels dropped below the USP acceptability threshold (<6.8), risking increased ocular irritation and reduced preservative efficacy.  they became visibly darker, and, notably, the Pakistani generic’s osmolality went marginally hypertonic (>320 mOsmol/kg), with the Refractive Index (RI) showing an unacceptable increase (>1.333), indicating significant solvent loss or solute buildup. Storing MOX ophthalmic solutions, especially the generics, under high temperature conditions a reality in hot climates seriously compromises their physicochemical integrity.