What is the bioavailability of CREATINE in humans upon oral ingestion
of large doses (5 grams and higher)?  We seek details about its
pharmacokinetics.

Hi saregamapa-ga, and thanks for your question.

The best source for information on this topic is likely the following
review article from the University of Florida and SUNY Buffalo:

Persky AM, Brazeau GA, Hochhaus G.  Pharmacokinetics of the dietary
supplement creatine.
Clin Pharmacokinet. 2003;42(6):557-74. 
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=12793840&query_hl=4&itool=pubmed_docsum

You can request a reprint of this article from Dr. Persky:
apersky@nc.rr.com

This article provides a detailed description of the synthesis,
metabolism, and pharmacokinetics of creatine.  The authors provide an
overview of the contributors of metabolism of creatine, which you can
view here:

http://img210.imageshack.us/img210/240/creatine15pl.png

A summary of pharmacokinetic parameters as measured in multiple
studies, including bioavailability, can be found in Table II, which
can be seen here:

http://img215.imageshack.us/img215/528/creatine21re.png


________________

The following article is freely available online and discusses the
pharmacology of creatine:

Persky AM, Brazeau GA. Clinical pharmacology of the dietary supplement
creatine monohydrate.
Pharmacol Rev. 2001 Jun;53(2):161-76. Review. 
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=11356982&itool=iconfft&query_hl=4&itool=pubmed_docsum

The full text is here:
http://www.ncbi.nlm.nih.gov/entrez/utils/lofref.fcgi?itool=Abstract&PrId=3051&uid=11356982&db=pubmed&url=http://pharmrev.aspetjournals.org/cgi/pmidlookup?view=long&pmid=11356982

________________

Here is another article of potential interest:

Absorption of creatine supplied as a drink, in meat or in solid form.
Roger C. Harris, Mary Nevill, D. Beorn Harris, Joanne L. Fallowfield,
Gregory C. Bogdanis and John A. Wise.  Journal of Sports Sciences 20.2
(Feb 2002): p147(5).
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed
You can request a reprint from Dr. Harris:
rharris@ucc.ac.uk


Here are some additional related articles:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Display&dopt=pubmed_pubmed&from_uid=12793840

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Display&dopt=pubmed_pubmed&from_uid=11356982


==========================

I hope this information is useful.  Please feel free to request
clarification prior to rating.

     -welte-ga

Excellent!