Background As many medicines are not available for paedriatic use they have to be elaborated in the pharmacy service. Generally, there are different formulations described in the bibliography.

Purpose To compare two liquid formulations of omeprazole elaborated in the pharmacy service of a tertiary hospital evaluating physicochemical stability and organoleptic characteristics (OC) with the aim of defining the most ideal formulation.

Material and methods A bibliographic check of the different formulations of omeprazole was carried out and two liquid magistral preparations were elaborated in triplicate. Formulation 1 was prepared from omeprazole monohydrate salt, using as excipients: simple syrup, mixture conservans and purified water. Formulation 2 was prepared from omeprazole capsules using bicarbonate 1 M as excipient. Conditions of refrigeration and of light protection were established. As an indicator of physicochemical stability, the pH was selected. For its determination a pH measurer, Mettler Toledo SevenMulti was used. The data was analysed using an Excel 2010 spreadsheet. The results were expressed as average ±SD. Also colour, smell and taste (OC) were evaluated, as well as homogeneity of the formulations. Thirty days was established as a period of study. The determinations were carried out on days 0,10,17,24 and 30 post-elaboration.

Results The pH was stable with barely any oscillations during the period of study. The data obtained for formulation 1 was: 8.476±0.012 (sample 1), 8.544±0.01 (sample 2) and 8.547±0.018 (sample 3). For formulation 2 it was: 6.777±0.026 (sample 1), 6.373±0.005 (sample 2) and 6.382±0.003 (sample 3).

The homogeneity of the formulations remained stable. The OC fluctuated significantly during the period of study. The colour of formulation 1 evolved from amber and opaque to dark brown, and the smell evolved from sweet to metallic and the taste (bitter-sweet) remained stable. In formulation 2 the opaque white colour and the disagreeable metallic smell remained unchanged. The taste changed, from very bitter to salty.

Conclusion In both formulations the pH remained stable.

The formulation based on raw material presents significant changes in OC, mainly in colour.

With regard to the formulation whose elaboration is made from capsules, the OC remained more stable.

As a result of this, it was decided to establish formulation 2 as a preferential formula in spite of its more disagreeable taste.

References and/or acknowledgements No conflict of interest.