Turmeric is a plant native to the Indian subcontinent and south-east asia. It is widely used as a medicinal herb in Ayurvedic and other ancient medical sciences. The main ingredient that is thought to be therapeutic is Curcumin (ref). Turmeric in Ayurvedic medications is either applied topically on the skin, or administered orally. We will begin our examination of turmeric by looking at its oral administration. To adapt the math model approach to turmeric, assuming curcumin is the active ingredient, one needs to know how much curcumin turmeric contains, how it is absorbed into the blood, how it distributes to the organs and how it is eliminated.
Each preparation of turmeric is said to have 1-7% of curcumin (ref). A lot of curcumin gets metabolized in the liver and the gut through what is known as the first pass metabolism (ref), which leads to low amount of curcumin in the blood when it is administered orally. About 33% of curcumin that is administered supposedly reaches the blood stream. Maximum concentration in the blood stream generally occurs 1-2 hours postdose and is found to decline within 12 hours. In a study which used an 8 g/day dose daily (ref), there was a peak blood concentration of 1.75 +/- 0.8 uM*. In a phase 1 study of Curcumin as a chemo preventive agent (ref), 25 patients were administered 3 doses of curcumin at 4, 6, and 8 g per day and blood concentrations of curcumin were recorded.
Using some massaging of parameters I described in a previous post (ref), I managed to make a PK model of curcumin in the format of what is generally called a 2 compartment PK model (ref). One fit for the dose of 4 g is shown below where the red line indicates our model prediction and the blue line indicates experimental data.
In the next post, we will study a sample pharmacodynamic model of turmeric.
