Related Experiment Video
Updated: Aug 19, 2026

Comprehensive Evaluation of the Effectiveness and Safety of Placenta-Targeted Drug Delivery Using Three Complementary Methods
Published on: September 10, 2018
Determination of plasma hydrochlorothiazide levels in humans
Abstract:
A method for determining plasma hydrochlorothiazide levels was developed with a sensitivity of 5 ng/ml. Accuracy and precision were demonstrated over the 5--648-ng/ml range by an overall recovery of 95 +/- 8%. The detector response was linear for the 5--250-ng/ml range. The method was sufficiently sensitive for hydrochlorothiazide bioavailability studies and also was applicable for the determination of whole blood drug levels. Plasma levels in two subjects reached peak levels of 428 and 450 ng/ml at 2.5 and 2 h, respectively, after a 50-mg dose. Whole blood levels at 3 hr after the same dose were 547 and 851 ng/ml and were approximately 2.5 times the 3-hr plasma levels.
Related Concept Videos
Factors Affecting Renal Clearance: Drug's Physicochemical Properties and Plasma Levels
One important factor is the drug's molecular size. The kidneys readily excrete smaller molecules below 300 Daltons (Da). On the other hand, molecules weighing between 300 and 500 Da are excreted through both urine and bile. Larger molecules above 500 Da tend to be excreted less...
Determination of Renal Drug Clearance: Graphical and Midpoint Methods
The graphical method involves plotting the rate of drug excretion in urine against the plasma drug concentration. By analyzing the graph, the clearance can be calculated and obtained. Drugs rapidly excreted by the kidneys exhibit a...
Determination of Multiple Dosing Parameters: Steady-State, Minimum and Maximum Concentrations
Determination of Multiple Dosing Parameters: Loading and Maintenance Doses
Drug Dosing in Renal Diseases: Measurement of Serum Creatinine Concentration and Clearance
Drug Dosing in Renal Diseases: Dose Adjustments Based on Drug Clearance and Elimination Rate Constant

