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Objectives To identify and analyze the phosphate concentration in glaucoma eye drops available in Spain. Material and methods Glaucoma medications containing phosphates were identified according to the 2013 Vademecum and the website of the Spanish Agency for Medicines and Medical Devices. Phosphate concentration was determined in these eye drops using ultraviolet molecular absorption spectrophotometry, and pH was determined using scan image analysis algorithms of pH strips. Results A total of 37 phosphate containing glaucoma eye drops were identified. The mean phosphate concentration was 97.72 ± 75.52 mM. The group with higher concentration of active substance was timolol (204.85 ± 42.38 mM) followed by brimonidine/timolol (200.9 mM). No statistically significant difference was found between brand name (95.65 ± 71.11 mM) and generic eye drops (99.14 ± 80 mM, p = 0.892). Although no statistically significant difference was found between products containing preservatives (99.24 ± 76.78 mM) and those without preservatives (85.17 ± 72.86 mM) (p = 0.730), a lower phosphate concentration was observed in the preservative-free Timolol and Latanoprost. Single dose samples showed a lower phosphate concentration than multi-dose ones (102.04 ± 75.39 vs. 22.24 ± 2.98 mM, p Conclusion The phosphate concentration in glaucoma eye drops exceeded the tear film physiological level (1.45 mM). No difference was observed between brand names and generic eye drops. Lower phosphate concentration was observed in preservative-free single dose eye drops.

Resumen Objetivo Determinar la concentracion de fosfatos y el pH de los colirios de lagrima artificial disponibles comercialmente en Espana. Material y metodos Se identificaron 71 lagrimas artificiales segun Vademecum 2014 y pagina web de la Agencia Espanola del Medicamento y Productos Sanitarios. En las 24 lagrimas cuya ficha tecnica indicaba que contenian fosfatos, se determino la concentracion de estos mediante espectrofotometria de absorcion molecular basada en radiacion ultravioleta y el pH mediante algoritmos de analisis de imagen por escaner a partir de tiras de papel. Resultados Se identificaron 71 lagrimas artificiales, de las cuales 24 contenian fosfatos entre sus excipientes; en 3 lagrimas la concentracion de estos era menor al umbral de deteccion ( Conclusion El 33,8% de las lagrimas contenian fosfatos (24 de 71). Consideramos que conocer la concentracion de fosfatos de las lagrimas artificiales es una informacion util que nos permitira evitar complicaciones potencialmente graves en pacientes de riesgo.

Objective To determine phosphate concentration and pH in artificial tear eye drops commercially available in Spain. Materials and methods A total of 71 examples of artificial tear preparations were identified in a search of Vademecum 2014 and the Spanish Medicines Agency website. In the 24 artificial tear products containing phosphates, quantification of these was performed by ultraviolet molecular absorption spectrophotometry, and the determination of pH was performed using scan image analysis algorithms of pH strips. Results Of the 71 artificial tears tested, 24 contained phosphate among their excipients in the data sheet, three of which had a concentration level below detection limit ( p = 0.0196) and hyaluronate ( p = 0.0067). Statistically significant differences were found between products containing preservatives (32.39 ± 20.91 mM), and preservative free ones (8.49 ± 11.98 mM) ( p = 0.0498). However, no difference was found between multidose (20.21 ± 26.91 mM) and unidose (9.31 ± 14.39 mM) samples, or between brand name (15.44 ± 23.3 mM) and generic eye drops (20.81 mM). The mean pH was 6.93 ± 0.26 (6.2–7.22). No statistical correlation was detected between phosphate concentration and pH (Spearman's Rho −0.1089 and p = 0.6125). Conclusion A total of 24 (33.8%) of the 71 artificial tears contained phosphate. We believe identifying the phosphate concentration of artificial tears is useful information in order to avoid complications in high-risk patients.

Resumen Objetivo Identificar y determinar la concentracion de fosfatos en colirios antiglaucomatosos comercializados en Espana. Material y metodo Se identificaron colirios antiglaucomatosos segun Vademecum 2013 y pagina web de la Agencia Espanola del Medicamento y Productos Sanitarios. En los que contenian fosfatos segun la ficha tecnica se determino la concentracion de estos mediante espectrofotometria de absorcion molecular basada en radiacion ultravioleta y el pH mediante algoritmos de analisis de imagen por escaner a partir de tiras de papel. Resultados Se registraron 37 colirios antiglaucomatosos con fosfatos. La media de la concentracion de fosfatos fue 97,72 ± 75,52 mM. El principio activo con mayor concentracion fue timolol (204,85 ± 42,38 mM) seguido de brimonidina/timolol (200,9 mM). No se registraron diferencias estadisticamente significativas entre los colirios de referencia de especialidad (95,65 ± 71,11 mM) y los genericos (99,14 ± 80 mM; p = 0,892). Tampoco se observaron diferencias entre aquellos con conservantes (99,24 ± 76,78 mM) y sin ellos (85,17 ± 72,86 mM; p = 0,730), aunque los principios de timolol y latanoprost presentaron menos fosfatos en su composicion sin conservantes. Las unidosis presentaron menos fosfatos que las multidosis (102,04 ± 75,39 vs. 22,24 ±2,98 mM; p Conclusiones La concentracion de fosfatos en todos los colirios superaba la concentracion fisiologica en la pelicula lagrimal (1,45 mM). No se observaron diferencias en la cantidad de fosfatos entre los medicamentos genericos y los de referencia de especialidad. Los antiglaucomatosos sin conservantes en unidosis presentaron menos fosfatos.

To determine phosphate concentration and pH in artificial tear eye drops commercially available in Spain.A total of 71 examples of artificial tear preparations were identified in a search of Vademecum 2014 and the Spanish Medicines Agency website. In the 24 artificial tear products containing phosphates, quantification of these was performed by ultraviolet molecular absorption spectrophotometry, and the determination of pH was performed using scan image analysis algorithms of pH strips.Of the 71 artificial tears tested, 24 contained phosphate among their excipients in the data sheet, three of which had a concentration level below detection limit (0.1mM). The mean phosphate concentration was 17.91±23.87mM. The artificial tear sample containing a higher concentration was Colircusi Humectante (87.1mM). Lubricants based on hypromellose showed the highest phosphate concentration (41.59±32.1mM), showing statistically significant differences compared to povidone (P=.0196) and hyaluronate (P=.0067). Statistically significant differences were found between products containing preservatives (32.39±20.91mM), and preservative free ones (8.49±11.98mM) (P=.0498). However, no difference was found between multidose (20.21±26.91mM) and unidose (9.31±14.39mM) samples, or between brand name (15.44±23.3mM) and generic eye drops (20.81mM). The mean pH was 6.93±0.26 (6.2-7.22). No statistical correlation was detected between phosphate concentration and pH (Spearman's Rho -0.1089 and P=.6125).A total of 24 (33.8%) of the 71 artificial tears contained phosphate. We believe identifying the phosphate concentration of artificial tears is useful information in order to avoid complications in high-risk patients.