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Dr. Bob is Robert Hsiung, MD,
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Posted by JohnX on March 2, 2001, at 4:38:58
Subject says it all.
What mechanism is used by SR meds (like Wellbutrin SR or Effexor XR) to reduce the absorbtion?Thnx for any answers.
-John
Posted by Cam W. on March 2, 2001, at 6:28:49
In reply to How do SR tablets differ from non SR tablets?, posted by JohnX on March 2, 2001, at 4:38:58
John - Wellbutrin SR is more slowly released from the tablet while in the gut, thus occurring in a slower rise to peak plasma drug concentrations. This leads to being able to take the Wellbutrin twice daily rather than 3 times daily. The fluctuations between minimum and maximum blood levels become more evened out using the SR version.
Hope this helps
Posted by danf on March 2, 2001, at 6:46:23
In reply to How do SR tablets differ from non SR tablets?, posted by JohnX on March 2, 2001, at 4:38:58
SRs get mixed with other materials that make the med a little insoluble & delay the med going into solution in the digestive fluids.
think of a hard candy ( jaw breaker ) verses granulated sugar. both are pretty much just sugar. the granulated sugar dissolves quickly. the jawe breaker takes a while.
same principle is applied to meds.
Posted by danf on March 2, 2001, at 6:57:26
In reply to Re: How do SR tablets differ from non SR tablets?, posted by danf on March 2, 2001, at 6:46:23
It is a physical process. some ( lots of med capsules )are made into tiny beads. beads are coated with different layers of a slow dissolving medically inert material.
there are several 'tricks' used. some are pH dependent, granule size, inert binder amounts, etc
most common method uses varying granule size & different coating thickness. so that some granules dissolve immediately, some in 1 hr, some in 2, etc.
dissolve time has to be played against gut transit time. over more than about 8-10 hrs & meds will be in the colon & have erratic absorption.
This is the end of the thread.
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