| Abstract: | Abstract A highly sensitive procedure for the determination of plasma levels of the antihistamine, chlorpheniramine (CPA) is presented. Following the administration of therapeutic doses (4–8 mg) of CPA, plasma levels of the drug can be expected to be low. To reliably and accurately measure such levels, an ultrasensitive means of determining the concentration is required. A preliminary extraction with ether, a back-wash into acid, a final basic extraction into hexane with subsequent measurement by a gas chromatograph equipped with a nitrogen sensitive detector, provides the required selectivity, sensitivity and speed of analysis. In an expenditure of less than 10 minutes, 1 ng of CPA per ml of plasma can be reliably determined. |
