Automated Mass Spec Technique to Detect Antidepressants

Scientists at Brown University have designed an automated liquid chromatography tandem mass spectrometry (LC-MS/MS) system that allows clinicians to rapidly and easily process patient samples to determine levels of antidepressant drugs in the body. Getting the correct dose of antidepressant drugs into the bloodstream is important to ensure efficacy and avoid side-effects. However, current assays to measure the levels of such drugs in the blood are cumbersome, require large blood samples, and involve multiple time-consuming steps, limiting their use by clinicians. This new system requires very small sample volumes, and employs a robot liquid handling system that is commonly found in clinical mass spectrometry labs to nearly entirely automate the assay. The researchers hope that the ease of use will increase such patient testing, resulting in improved treatment outcomes.

Antidepressant drugs can be very effective for those with depression, but getting the dose right is important. Too little and the patient may not experience the full benefit of the treatment. Too much can lead to some potentially serious side-effects. Moreover, simply prescribing a fixed dose based on someone’s bodyweight is not the best way to achieve optimal levels in the blood, since interindividual differences in physiology, such as differing levels of certain liver enzymes, can result in drastically different levels of a drug reaching and staying in the bloodstream.

The best way to personalize and optimize drug treatment is to actually monitor how much drug is present in the blood during treatment. However, the LC-MS/MS approaches for such measurements are cumbersome, requiring relatively large volumes of blood, necessitating a blood draw rather than a finger prick. They also involve multiple steps that require some skill and must be performed manually by skilled lab technicians.

To address this, these researchers have developed an automated system that requires just 20 microliters of blood per sample, allowing finger prick samples. This is much more convenient for patients and clinicians alike. Moreover, the time consuming manual sample prep steps are now conducted automatically by a robotic liquid handling system.

“We designed our method and put together kits so that once the samples have been collected, they can be put in a computer program for a robotic liquid handler, and all the user essentially has to do is take off the caps, press some buttons, and it will go start to finish,” said Ramisa Fariha, a researcher involved in the study.       

Study in journal Scientific Reports: An in-depth analysis of four classes of antidepressants quantification from human serum using LC–MS/MS

Via: Brown