Plasma marijuana smokers

This antiserum was used in the blind analysis of plasma samples from marijuana smokers. These samples were also analyzed by GC-MS at Battelle Institute. Regression analysis of the two sets of results showed good agreement RIA (ng/ml) = 1.2 GC + 0.14 with excellent correlation. Thus, the tritium labeled A8-THC combined with the antibody from the A9-immunogen is useful for the analysis of A9-THC in plasma. 

Figure 1. HPLC analysis of 1 mL human plasma from non-marijuana smokers to which 1.0 /xg of 11 (CBD), 0.25 p.g of 111 (CBN), 1.0 /xg of I ( S-THC), and 0.25 ixg of IV (CBC) were added. A gradient program (solid superimposed line) was used starting with 95 5, heptane methylene chloride.

Figure 4. HPLC analysis of (-----), human plasma from a non-marijuana smoker...

Figure 5. HPLC analysis of human plasma from a marijuana smoker to which yill (A9-u-THC) has been added as internal standard. Mobile phase of 0.6% isopropyl alcohol in heptane used on a tandem alkylamine—alkylnitrile column with a flow rate of 60 mL/hr.

If however, detection was the objective, 5 ng/ml limit was practical in the tandem method. As with the other HPLC techniques, this method was compared to the reference HPLC-MS technique. Table V gives data obtained on plasma from a marijuana smoker using both methods. The only notable variance between the two methods occurred with the two hour sample which was received by our laboratory in a broken tube. 

Once the extracting and HPLC conditions were worked out the method was evaluated in plasma of a marijuana smoker. 

Figure 6. HPLC analysis of human plasma from a non-marijuana smoker to which 100 ng/mL of VI has been added. A gradient (superimposed with dashed line) beginning with 60 40, water-.acetonitrile was used on a phenyl-bonded phase...

The expert smoker of marijuana is usually aware of a drug effect after two or three inhalations. As smoking continues, the effects increase, reaching a maximum about 20 minutes after the smoke has been finished. Most effects of the drug usually have vanished after 3 hours, by which time plasma concentrations are low. Peak effects after oral administration may be delayed until 3-4 hours after... 

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