Limitations and Challenges in the Stability of Cysteamine Eye Drop Compounded Formulations



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Martín Sabroso, Cristina and Alonso González, Mario and Fernández Carballido, Ana María and Aparicio Blanco, Juan and Córdoba Díaz, Damián and Navarro García, Federico and Córdoba Díaz, Manuel and Torres Suárez, Ana Isabel (2022) Limitations and Challenges in the Stability of Cysteamine Eye Drop Compounded Formulations. Pharmaceuticals, 15 (2). pp. 1-18. ISSN 1424-8247

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Accumulation of cystine crystals in the cornea of patients suffering from cystinosis is considered pathognomonic and can lead to severe ocular complications. Cysteamine eye drop compounded formulations, commonly prepared by hospital pharmacy services, are meant to diminish the build-up of corneal cystine crystals. The objective of this work was to analyze whether the shelf life proposed for six formulations prepared following different protocols used in hospital pharmacies is adequate to guarantee the quality and efficacy of cysteamine eye drops. The long-term and in-use stabilities of these preparations were studied using different parameters: content of cysteamine and its main degradation product cystamine; appearance, color and odor; pH and viscosity; and microbiological analysis. The results obtained show that degradation of cysteamine was between 20% and 50% after one month of storage in the long-term stability study and between 35% and 60% in the in-use study. These data confirm that cysteamine is a very unstable molecule in aqueous solution, the presence of oxygen being the main degradation factor. Saturation with nitrogen gas of the solutions offers a means of reducing cysteamine degradation. Overall, all the formulae studied presented high instability at the end of their shelf life, suggesting that their clinical efficacy might be dramatically compromised.

Item Type:Article
Uncontrolled Keywords:Cysteamine; Ocular cystinosis; Stability; Eye drop formulations
Subjects:Medical sciences > Pharmacy > Pharmaceutical technology
ID Code:75923
Deposited On:20 Dec 2022 08:50
Last Modified:20 Dec 2022 13:41

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