Stability of Esomeprazole Capsule Contents After In Vitro Suspension in Common Soft Foods and Beverages

David A. Johnson, M.D., FACP, FACG, Albert C. Roach, Pharm.D., FACG, Anders S. Carlsson, M.Sc., Anders A.S. Karlsson, Ph.D., Dan E. Behr, Ph.D.


Pharmacotherapy. 2003;23(6) 

In This Article

Materials and Methods

Single esomeprazole 20-mg capsules (Nexium, AstraZeneca, Wilmington DE) were opened, and their contents were weighed and emptied into individual USP vessels containing 100 ml of one of the following beverages: natural yogurt, tap water, orange juice, apple juice, milk (1.5% fat), and cultured milk (3% fat [a popular beverage in Nordic countries]). Measurements of pH were assessed using a mobile MP 120 pH meter with a Mettler Toledo Inlab 418 electrode (Mettler Toledo AG, Schwerzenbach, Switzerland). After 30 minutes, 500 ml of 0.1 M hydrochloric acid was added to each vessel. After 2 hours, pH values were measured, and the pellets were collected and transferred into a 250-ml volumetric flask containing approximately 100 ml water. Phosphate buffer solution (50 ml, pH 11.0) was added, and the mixture was agitated in a shaking machine for 20 minutes. After another 5 minutes in an ultrasonic bath at ambient temperature,the flask was shaken by hand, and 50 ml of 95% ethanol was added. Next, the flask was shaken by hand again, and the contents were filtered through a Munktell 1F filter (Munktell Filter AB, Grycksbo, Sweden). The filtrate was diluted 5 times with water before measurement, using a reverse-phase liquid chromatography method with ultraviolet detection at 302 nm and a flow rate of 1.0 ml/minute. The column used was a Zorbax Eclipse XDB C18, 5 µm, length 150 mm, ID 4.6 mm (Agilent Technologies, Palo Alto, CA) with guard column Zorbax Eclipse XDB C18, 5 µm, length 12.5 mm, ID 4.6 mm. The mobile phase contained 350 ml acetonitrile and 500 ml phosphate buffer solution at pH 7.3. This mixture was diluted to 1000 ml with water.

The recovery of esomeprazole was calculated by multiplying the final volume by the final esomeprazole concentration. Acid resistance (stability) was assessed as the mass recovered, divided by the original mass. Each experiment was performed in triplicate, and the results reported as arithmetic means.


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