An example HPLC chromatogram for an actual plasma sample from a reindeer treated with ivermectin by oral administration of equine paste (Group 2) at the dose of 200 μg/kg. Sample from day 2 post treatment, concentration determined to 9 ng/ml. HPLC detector attenuation: 3. Each plasma sample for analysis (1.0 ml) was supplemented with 10 ng abamectin (internal standard) before extraction and sample preparation. The plasma concentration calculation was based on the HPLC software-generated heights of the ivermectin B1a and abamectin Bla peaks using the equation given above.