An integration assay with the use of PICs that were preincubated with cocaine (50 µM) or Raltegravir (1 µM) for 15 min on ice. Thereafter, Raltegravir was added to cocaine, preincubated PICs, and cocaine was added to Raltegravir preincubated PICs before the integration assay. Integrated viral DNA copy numbers were determined by plotting values derived from a standard curve. (Inset) Relative integration of preincubated PICs with Raltegravir compared with PICs preincubated with cocaine. Controls, such as PICs alone, PICs + cocaine, PICs + RAL, target DNA alone, cocaine + target DNA, lysates from uninfected cells, lysates from uninfected cells + cocaine, and lysates from uninfected cells + target DNA, showed no integration activity. Data are presented as mean values, with error bars indicating sd of triplicate measurements.