Compatibility of Flavoring Agents in Compounding Extemporaneous Omeprazole Oral Liquid

In a previous study, the results of which were provided in an article published in the International Journal of Pharmaceutical Compounding, it was determined that FLAVORx's Grape flavor in extemporaneously compounded omeprazole oral liquid was found suitable. A follow-up study was conducted in which the authors explored four additional flavors (Professional Compounding Centers of America's Cherry Concentrate and their Orange Concentrate, and FLAVORx's Bubble Gum flavor and their Watermelon flavor) to allow pharmacists and patients greater flexibility and options to flavor omeprazole oral liquid. Oral liquids were compounded using 20-mg omeprazole delayed-release capsules, 8.4% sodium bicarbonate, and each of four flavors to reach drug concentration at 2 mg/mL and flavor at 1.2% v/v (n=3). After the delayed-release pellets were disintegrated, the prescription bottles were stored in cold temperature overnight. For flavor alone in 8.4% sodium bicarbonate solution, samples were prepared the same as above except no omeprazole delayed-release capsules were added. High-performance liquid chromatographic assay was adopted from the United States Pharmacopeia's Omeprazole Monograph, but it is for the unflavored oral liquid. In order to ensure assay robustness, stability indication tests, 0.1 N HCl (acid), 0.1 N NaOH (base), 50°C (heat), and 3% hydrogen peroxide were also performed to the flavored omeprazole oral liquids, as well as to the individual flavor alone in sodium bicarbonate solution without omeprazole. Professional Compounding Centers of America's Cherry Concentrate, Orange Concentrate, and FLAVORx's Watermelon flavor showed no interference with the drug, and the assays were robust. However, FLAVORx's Bubble Gum flavor displayed five mini peaks at 280 nm with one embedded in omeprazole peak. The resolution of a Bubble Gum peak immediately next to an omeprazole peak computed by column kinetics was 0.91, while the separation factor was 1.15. A good separation is generally >1.5. This study examined only the Cherry Concentrate, Orange Concentrate, Bubble Gum flavor, and Watermelon flavor from the specified manufacturers. An insignificant interference was shown between FLAVORx's Bubble Gum flavor with omeprazole. The results are not intended to infer that all brands of the same flavor names would react the same way. Omeprazole and all four studied flavors should be protected from oxidation insult.