A sensitive quantitative method for drug concentrations in blood based on surface-enhanced Raman spectroscopy

The treatment of cardiovascular surgery relies on precise medication management at every stage. Blood contains a wealth of pharmacokinetic and pharmacodynamic information that provides an important basis for personalized drug delivery. Rapid and highly sensitive blood drug concentration assays can dynamically assess the distribution and metabolism of drugs in the body, optimize dose adjustment and improve therapeutic efficacy and safety. This study proposed a new method for real-time monitoring of cardiovascular drugs that combines the surface enhanced Raman spectroscopy (SERS) detection platform with a two-phase extraction strategy. First, silver nanoparticles were synthesized and modified with iodine ions, and calcium ions were further introduced to enhance the stability of the substrate and the Raman signal intensity. Subsequently, common interfering substances in plasma were removed by protein precipitation technology, and drug molecules were rapidly enriched by two-phase extraction to obtain a purer test sample. The experimental results showed that the method had good repeatability (RSD = 2.18 %), the minimum detection concentration of propranolol could reach 10 pg/mL, and the minimum detection limit of atropine was 500 pg/mL. In the SD rat model, the blood concentration of atropine reached a peak at about 2 h after oral administration. In addition, the animal model further demonstrated the ability of this method to accurately monitor the dynamic changes of blood drug concentrations. By comparing with the conventional detection results of UHPLC-MS/MS, the accuracy of this method in quantitative analysis was verified. This study not only expands the application potential of SERS technology in the detection of complex biological samples, but also highlights its broad prospects in drug analysis and clinical individualized treatment.