extended release/weekly meds

[cchalk]

Hi, does anyone know how these types of meds work and stay in you system giving you (constant?) a dose of the med?

Thanks.

Regards,

cchalk

[cchalk]

Ok, I seem to have found the answer to my question. From the wikipedia article:

"Sustained-release (SR), extended-release (ER, XR, or XL), time-release or timed-release, controlled-release (CR), or continuous-release (CR or Contin) pills are tablets or capsules formulated to dissolve slowly and release a drug over time. The advantages of sustained-release tablets or capsules are that they can often be taken less frequently than instant-release formulations of the same drug, and that they keep steadier levels of the drug in the bloodstream. Sustained-release tablets are formulated so that the active ingredient is embedded in a matrix of insoluble substance (various: some acrylics, even chitin, these are often patented) so that the dissolving drug has to find its way out through the holes in the matrix. In some SR formulations the matrix physically swells up to form a gel, so that the drug has first to dissolve in matrix, then exit through the outer surface.

There are certain considerations for the formation of sustained release formulation:

If the active compound has a long half-life (over six hours), it is sustained on its own.

If the pharmacological activity of the active is not related to its blood levels, time releasing then has no purpose.

If the absorption of the active involves an active transport, the development of a time-release product may be problematic.

Finally, if the active has a short half-life, it would require a large amount to maintain a prolonged effective dose. in this case, a broad therapeutic window is necessary to avoid toxicity; otherwise, the risk is unworthy to take and another mode of administration would be recommended.

Difference between controlled release and sustained release is that controlled release is perfectly zero order release that is,the drug releases with time irrespective of concentration. On the other hand, sustained release implies slow release of the drug over a time period. It may or may not be controlled release."

The page history shows only a handful of authors, and one user Galaxiaad (could be a lie you never know) is a pharmacy technician in Philadelphia.

Edit: Found this interesting bit on the talk page:

"Patent stuff

I copied the following from the main page (references section) as I have doubts about its usefulness in an encyclopedia. I'll research it more later, but for now... --Galaxiaad 08:24, 14 February 2007 (UTC)

http://www.pharmakodex.co.uk/technologies.html PharmaKodex has six proprietary technology platforms, five directed towards oral medicines…

Pharmaceutical controlled release tablets containing a carrier made of cross-linked amylose and hydroxypropylmethylcellulose

Document Type and Number: United States Patent 5885615 Link to this Page: http://www.freepatentsonline.com/5885615.html

Abstract: Disclosed is a pharmaceutical controlled release tablet containing an active ingredient in combination with a carrier made of cross-linked amylose in which hydroxymethylpropylcellulose (HPMC) with a viscosity higher than or equal to 4000 cps is added as an adjuvant. The addition of HPMC to the tablet permits to control the effect of enzymes, and more particular alpha-amylase present in the intestinal medium, on the cross-linked amylose used as a carrier, and thus to reduce the dependence of the kinetics of release upon the concentration of enzymes present in the medium.

Immediate release tablet Document Type and Number: United States Patent 6521253 Link to this Page: http://www.freepatentsonline.com/6521253.html

Abstract: A new oral IR formulation in solid form for a low molecular weight thrombin inhibitor having pH dependant dissolution, characterized in that the formulation comprises a filler or a combination of fillers having disintegrant properties in an amount higher than 35% w/w of the formulation.

http://www.pharmcast.com/PatentToSubWeb/Cl...ication1200.htm Controlled/Sustained/Delayed Release Drug Delivery System, General 1. Pharmacological compositions comprising pectins having high molecular weights and low degrees of methoxylation 2. Once a day antihistamine and decongestant formulation…. up to 134. each one a clickable link. This looks a promising starting point.

http://www.pharmaquality.com/mag/102005/pfq_102005_FO1.html gives an overview of gums / gels, used for even, slow release – describes the gum only, otherwise not informative.

http://www.pharmcast.com/Patents100/Yr2004...axine022404.htm gives a detailed description of the patent used for slow-release Efexor.

http://www.drugresourcecenter.com/kdur/kdur.htm

Extended-Release Formulation for Liquid Suspension Potassium chloride liquid suspension is an oral dosage form of microencapsulated potassium chloride.

Each packet contains 1.5 g of potassium chloride, USP equivalent to 20 mEq of ...

Tech storm sweeps tableting http://www.pharmabiz.com/article/detnews.a...mp;sectionid=50 Industrially Feasible Alternative Approaches in the Manufacture of Solid Dispersions: A Technical Report. A detailed academic paper on production of a delivery system."

And the funny thing is I don't even take any extended release type meds. lol