roxi*stardust
05-11-2008, 10:08 AM
TIME RELEASE OXYCODONE (OXYCONTIN):
MECHANISM:
PHARMACOKINETICS
The activity of OxyContin Tablets is primarily due to the parent drug oxycodone.
OxyContin Tablets are designed to provide controlled delivery of oxycodone over 8-12 hours.
Oxycodone release from OxyContin Tablets is pH independent. Oxycodone is well absorbed from OxyContin Tablets with an oral bioavailability of 60% to 87%. The relative oral bioavailability of OxyContin to immediate-release oral dosage forms is 100%. Upon repeated dosing in normal volunteers in pharmacokinetic studies, steady-state levels were achieved within 24-36 hours. Dose proportionality and/or bioavailability has been established for the 10 mg, 20 mg, 40 mg, 80 mg, and 160 mg tablet strengths for both peak plasma levels (C
max) and extent of absorption (AUC).
Oxycodone is extensively metabolized and eliminated primarily in the urine as both conjugated and unconjugated metabolites. The apparent elimination half-life of oxycodone following the administration of OxyContin® was 4.5 hours compared to 3.2 hours for immediate-release oxycodone.
About 60% to 87% of an oral dose of oxycodone reaches the central compartment in comparison to a parenteral dose. This high oral bioavailability is due to low pre-systemic and/or first-pass metabolism. In normal volunteers, the t˝ of absorption is 0.4 hours for immediate-release oral oxycodone. In contrast, OxyContin Tablets exhibit a biphasic absorption pattern with two apparent absorption half-lives of 0.6 and 6.9 hours, which describes the initial release of oxycodone from the tablet followed by a prolonged release.
Dose proportionality has been established for the 10 mg, 20 mg, 40 mg, and 80 mg tablet strengths for both peak plasma concentrations (C max) and extent of absorption (AUC) (see Table 1 below). Another study established that the 160 mg tablet is bioequivalent to 2 x 80 mg tablets as well as to 4 x 40 mg for both peak plasma concentrations (Cmax) and extent of absorption (AUC) (see Table 2 below). Given the short half-life of elimination of oxycodone from OxyContin®, steady-state plasma concentrations of oxycodone are achieved within 24-36 hours of initiation of dosing with OxyContin Tablets. In a study comparing 10 mg of OxyContin every 12 hours to 5 mg of immediate-release oxycodone every 6 hours, the two treatments were found to be equivalent for AUC and Cmax, and similar for Cmin (trough) concentrations. There was less fluctuation in plasma concentrations for the OxyContin Tablets than for the immediate-release formulation.
Here is a graph showing plasma concentrations after a single dose of each strength, and a steady dose of the 10mg tablet. The graph shows there is definately and intial release of a "loading" dose from the pill because plasma levels go from zero to peak within the first 1-2 hours then taper down slowly. No doubt in my mind that you get about 1/3 of the dose intially then the other 2/3 slowly.
2772
CLICK ME!!!!!
Okay I came into some 40mg OxyContin and ive taken them normally i.e. no crushing etc.. just swallow em as is. I know they are time release but just how is it broken down ? Does it give you a certain amount of oxy every 3-4 hours ? If so how much ? Is one dose stronger than the next ? I also realize people metabolize at diff rates but curious if there is a generic breakdown.
See the sticky above "Questions about Oxycodone", it describes the Pharmacokinetics and Metabolism of OxyContin Tablets. There are also a few threads. Search engine:
http://forum.opiophile.org/showthread.php?t=14790&highlight=oxycontin+release+works
http://forum.opiophile.org/showthread.php?t=7197&highlight=oxycontin+release+works
The sticky above provides info directly from Purdue.
Since there are a bunch of threads with this same info I am going to close this one. I have pasted the post into this thread that has the most info.
Don't ask me why it posted it at the beginning of the thread but it did; no matter the info is here-thread closed
MECHANISM:
PHARMACOKINETICS
The activity of OxyContin Tablets is primarily due to the parent drug oxycodone.
OxyContin Tablets are designed to provide controlled delivery of oxycodone over 8-12 hours.
Oxycodone release from OxyContin Tablets is pH independent. Oxycodone is well absorbed from OxyContin Tablets with an oral bioavailability of 60% to 87%. The relative oral bioavailability of OxyContin to immediate-release oral dosage forms is 100%. Upon repeated dosing in normal volunteers in pharmacokinetic studies, steady-state levels were achieved within 24-36 hours. Dose proportionality and/or bioavailability has been established for the 10 mg, 20 mg, 40 mg, 80 mg, and 160 mg tablet strengths for both peak plasma levels (C
max) and extent of absorption (AUC).
Oxycodone is extensively metabolized and eliminated primarily in the urine as both conjugated and unconjugated metabolites. The apparent elimination half-life of oxycodone following the administration of OxyContin® was 4.5 hours compared to 3.2 hours for immediate-release oxycodone.
About 60% to 87% of an oral dose of oxycodone reaches the central compartment in comparison to a parenteral dose. This high oral bioavailability is due to low pre-systemic and/or first-pass metabolism. In normal volunteers, the t˝ of absorption is 0.4 hours for immediate-release oral oxycodone. In contrast, OxyContin Tablets exhibit a biphasic absorption pattern with two apparent absorption half-lives of 0.6 and 6.9 hours, which describes the initial release of oxycodone from the tablet followed by a prolonged release.
Dose proportionality has been established for the 10 mg, 20 mg, 40 mg, and 80 mg tablet strengths for both peak plasma concentrations (C max) and extent of absorption (AUC) (see Table 1 below). Another study established that the 160 mg tablet is bioequivalent to 2 x 80 mg tablets as well as to 4 x 40 mg for both peak plasma concentrations (Cmax) and extent of absorption (AUC) (see Table 2 below). Given the short half-life of elimination of oxycodone from OxyContin®, steady-state plasma concentrations of oxycodone are achieved within 24-36 hours of initiation of dosing with OxyContin Tablets. In a study comparing 10 mg of OxyContin every 12 hours to 5 mg of immediate-release oxycodone every 6 hours, the two treatments were found to be equivalent for AUC and Cmax, and similar for Cmin (trough) concentrations. There was less fluctuation in plasma concentrations for the OxyContin Tablets than for the immediate-release formulation.
Here is a graph showing plasma concentrations after a single dose of each strength, and a steady dose of the 10mg tablet. The graph shows there is definately and intial release of a "loading" dose from the pill because plasma levels go from zero to peak within the first 1-2 hours then taper down slowly. No doubt in my mind that you get about 1/3 of the dose intially then the other 2/3 slowly.
2772
CLICK ME!!!!!
Okay I came into some 40mg OxyContin and ive taken them normally i.e. no crushing etc.. just swallow em as is. I know they are time release but just how is it broken down ? Does it give you a certain amount of oxy every 3-4 hours ? If so how much ? Is one dose stronger than the next ? I also realize people metabolize at diff rates but curious if there is a generic breakdown.
See the sticky above "Questions about Oxycodone", it describes the Pharmacokinetics and Metabolism of OxyContin Tablets. There are also a few threads. Search engine:
http://forum.opiophile.org/showthread.php?t=14790&highlight=oxycontin+release+works
http://forum.opiophile.org/showthread.php?t=7197&highlight=oxycontin+release+works
The sticky above provides info directly from Purdue.
Since there are a bunch of threads with this same info I am going to close this one. I have pasted the post into this thread that has the most info.
Don't ask me why it posted it at the beginning of the thread but it did; no matter the info is here-thread closed