Magazine article Drug Topics

Delayed-Release Drug Not Enteric-coated/Reply from the Authors

Magazine article Drug Topics

Delayed-Release Drug Not Enteric-coated/Reply from the Authors

Article excerpt

In your July 23 FDA Safety Page, "Delayed-release vs. extended-release Rxs," Ms. Holquist and Mr. Fava accurately report how multiple formulations of the same medication can lead to medication errors. However, twice the authors refer to Depakote (delayed-release) and Depakote ER (extended-release) as enteric-coated tablets. Although the delayed-release Depakote formulation is an enteric-coated product, Depakote ER is not. Depakote ER features a hydrophilic polymer matrix system that controls drug release primarily by the process of polymer swelling, erosion, and drug diffusion. Specifically, the tablet film coating dissolves upon entering the stomach, exposing the hydrophilic polymer matrix tablet. The outer layer of the matrix becomes partially hydrated, forming a gel layer, and the drug begins to be released. As fluid permeates the tablet, the gel layer increases in thickness, extending the release of drug. Once the outer layer becomes fully hydrated, it erodes and is released from the tablet. Fluid continues to penetrate toward the tablet core. When the hydration process is complete, the last of the drug is absorbed 1 8 to 24 hours following ingestion.

After administration, absorption occurs immediately; however, since the absorption is considered multi-phasic, only about 15% of the dose is absorbed in the first two hours. Within 12 hours, about 53% of the total dose is absorbed, with complete absorption occurring over 20 to 24 hours. The article does a thorough job of defining and describing the difference between delayed-release and extended-release formulations, but enteric coating and an extended-release delivery system are not the same.

D. Hill, R.Ph.

Clinical Pharmacist

Forum Extended Care

htllpill@ameritech.net

Depakote ER is not enteric-coated; however, Depakote delayed-release is enteric-coated.

Reply from the authors: The authors incorrectly identified Depakote ER as an enteric-coated product. Depakote ER is not enteric-coated; however, Depakote delayed-release is enteric-coated. The authors did not state or imply that enteric-coated is the same as extended-release. The information presented on the bioavailability differences between Depakote delayed-release and Depakote extended-release is accurate.

R.Ph.s losing out on IVITIVl payment

Over the past year I have read a lot about medication therapy management (MTM), and I think that on the whole it is a good thing-not just for the pharmacy profession but also for patients. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.