Compatibility of proton pump inhibitors in a preservative-free suspending vehicle

To evaluate the microbiological and physicochemical compatibility of commonly used proton pump inhibitors (PPIs) esomeprazole, lansoprazole, omeprazole and pantoprazole compounded at a single concentration using SyrSpend SF Alka and stored at refrigerated temperatures (omeprazole was also stored at room temperature because it has the most widespread use).

Compatibility was assessed by measuring the per cent recovery at varying time points throughout a 90-day period. Quantification of the APIs was performed by a validated high performance liquid chromatography (HPLC-UV) method. This same assay was also used to determine the dosage content uniformity of the suspensions. Microbiological stability ('test in use') was assessed during 60 days and total aerobic microbial count (TAMC), total combined yeasts and moulds count (TYMC), detection of Escherichia coli and pH determination were performed. Antimicrobial effectiveness testing was determined following European Pharmacopoeia guidelines.

Beyond-use dates of maximum 60 days for omeprazole (5 mg/mL), pantoprazole (3 mg/mL) and esomeprazole (3 mg/mL) were established. All suspensions that met the physicochemical criteria for stability also met the content uniformity criteria. The suspensions showed no antimicrobial efficiency against bacteria, yeasts and moulds as SyrSpend SF Alka is an unpreserved vehicle, but the 'test in use' showed that the suspensions can remain microbiologically stable for up to 60 days.

SyrSpend SF Alka can be used to compound palatable (taste-masking properties) preservative-free oral suspensions with almost all commonly used PPIs.