Omeprazole – a new raw material for drug compounding

Abstract

One of the more common performed magistral drugs are formulations containing omeprazol. Lack of omeprazole registered as compunding raw material forced use of industrially manufactured medicines in the pellets form. The introduction of omeprazole as a pharmaceutical raw material into the pharmaceutical market facilitates the drug compounding. However, it is necessary to consider the possibility of decomposition of the substance in an acidic environment. The aim of this study was to evaluate the stability of magistral suspensions with omeprazole containing glycerol, simple syrup or glucose. Sodium bicarbonate at a concentration of 8% was used to ensure the proper pH. Six suspensions were formulated and tested after preparation and after 1, 2, 3 and 4 weeks of storage at room temperature and in the refrigerator. Their physicochemical characteristics (sedimentation time, number of shakes required to redisperse the mixture), and the stability of the active substance (pH of suspensions and omeprazole content) were analyzed. Tested preparations turned yellow-brown during storage at room temperaturę after just two days. This phenomenon was not observed in the prepared suspensions stored in the refrigerator. Addition of glycerol or simple syrup facilitated the dispersion of omeprazole and contributed to the formation of smaller aggregates. Mixtures with glycerol and simple syrup underwent slower sedimentation (20 minutes) than the preparations with glucose (15 minutes), however the precipitate formed during storage was very easily dispersible in all analyzed formulations. A ten-second shake was enough to obtain uniform dispersion. The pH value of the examined suspensions was about 8.86. During their four-week storage, the pH increased to 9.23 - 9.45 in the suspensions stored at room temperature, and to 9.17 - 9.24 in the preparations stored in the refrigerator. According to the requirements posted in the USP (United States Pharmacopoeia), the suspensions in which the amount of omeprazole was equal to or greater than 90% of the initial content were considered stable. Active ingredient content above 90% was demonstrated for all designed suspensions stored for two weeks. Due to the faster decomposition of omeprazole when exposed to elevated temperature, omeprazole suspensions should be stored in the refrigerator and used within 14 days.

Keywords

• suspension
• omperazole
• magistral drugs
• stability testing