High Resolution Accurate Mass Spectrometry in Clinical Toxicology. William Clarke, PhD, MBA, DABCC Johns Hopkins University School of Medicine

Transcription

1 High Resolution Accurate Mass Spectrometry in Clinical Toxicology Applied to an ED HIV Study William Clarke, PhD, MBA, DABCC Johns Hopkins University School of Medicine Disclosure William Clarke, PhD received compensation from Thermo Fisher in the form of travel support to give this talk, and has received research support from Thermo Fisher. All opinions expressed and implied in this presentation are solely those of William Clarke. The content of the presentation does not represent or reflect the views of the Johns Hopkins University or the Johns Hopkins Hospital and Health System. All potential conflicts of interest are dislosed and managed through the Johns Hopkins University Office of Policy Coordination 1

2 Clinical vs. Forensic Toxicology Clinical Blood or Urine specimens Sometimes meconium Need rapid TAT Patient care focused Examples: ED/Acute Care Pain Management/Rehab Pre surgical testing Evaluation of chronic toxic symptoms Forensic Wider variety of sample types Different time frames for analysis Focused on investigation rather than patient care Examples: Crime investigations Post mortem toxicology Workplace drug testing and pre employment screening Clinical Toxicology Then & Now 2

3 High Resolution Accurate Mass MS Often performed with FT ion trap instruments (FT ICR, orbitrap) or TOF instruments Resolution ranging from 20K to 140K dependent on instrument selected Mass accuracy should be < 1ppm Exact Mass Ion Trap 3

4 Exactive System Resolution 100,000 at 1 scan per second 10,000 at 10 scans per second Octapole ion guiding Mass accuracy Sub ppm Dynamic range >10,000 within a spectrum Scan speed Up to 10 scans per second Mass range m/z Polarity switching One positive and one negative scan < 1 second (25K Resolution) Orbitrap Principle of Operation A short ion packet of one m/z from c trap enters the field tangentially C trap is only used as an ion storage device Ions are squeezed towards the central electrode by increasing voltage on the central electrode In the axial direction, ions are forced to move away from the narrow gap towards the wider gap near the equator. This initiates axial oscillations After the voltage increase stops, ion trajectories become a stable spiral 4

5 Orbitrap Principle of Operation Ion m/z separation depends on Frequency of harmonic oscillations and is proportional to sq root of M/Z Three frequencies create oscillations Frequency of rotation Frequency of radial oscillations Frequency of axial oscillations Resolving power is Inversely proportional to the square root of M/Z Proportional to acquisition time Sensitivity is independent of acquisition speed Red rings smallest m/z; Blue ring larger m/z; Green ring largest m/z Makarov A. Anal. Chem. 2000, 72, HRMS Video 5

6 ED Serum Toxicology Analysis Our lab serves as the Toxicology Core for the HPTN Network Lab HPTN = HIV Prevention Trials Network Responsible for evaluating existing technologies and developing/validating new methods One project involves analyzing serum specimens characterized with respect to HIV and hepatitis infection 4500 JHH specimens from 2007 Amphetamines, opiates, cocaine, marijuana Screening Targets Morphine Glucuronide Morphine Hydromorphone Acetylmorphine Methamphetamine Ampetamine MDMA Cannabinol Cocaine Benzoylecgonine Cocaethylene Normorphine THC Norcocaine 6

7 LC Method Sample Prep Cold ACN precipitation Evaporate, MeOH reconstitution Column Hypersil GOLD PFP 150 x 2.1 mm, 5 m Mobile phase A: 10 mm NH4FA, 0.1%FA in DI water B: 10 mm NH4FA, 0.1%FA in MeOH C: ACN/IPA/Acetone = 45/45/10 (v/v/v) Ionization Parameters HESI probe Positive ionization mode Spray voltage: 4000 V Vaporizer temperature: 350 o C Sheath gas: 25 units Aux gas: 35 units Sweep gas: off Capillary temperature: 320 o C 7

8 Representative Data Initial Data Summary 98 HIV positive patients screened using Exactive; only positive results confirmed with SRM by QQQ were reported None were positive for THC 32.5% were positive for cocaine 21.5% were positive for opiates The remainder of the specimens are to be screened for the same compounds 8

9 Additional Information (HIV Drugs) Performing the full scan with an Exactive mass analyzer (or TOF MS) detects all ions and allows for retrospective data queries Performed an in silico screening for HIV medications (database matching based on exact mass measurement +/ 5 ppm) Retention time not a factor Screened for 36 HIV drugs and metabolites 28.5% of HIV positive patients demonstrated detectable concentrations of HIV medication Example of patient sample data Emtricitabine Hydroxy Emtricitabine Ritonavir Darunavir Atazanavir Hydroxy Atazanavir 9

10 Emtricitabine:Theoretical isotopic pattern Patient sample: Emtricitabine peak and the experimental isotopic pattern 10

11 Emtricitabine: Three most abundant fragments predicted by Mass Frontier software m/z= m/z= m/z= Emtricitabine: chromatograms of parent ion and fragments and all ions spectrum Chromatograms reconstructed with mass accuracy of 5 ppm SCID all ion spectrum m/z= in full scan Fragment m/z= Reconstructed chromatograms of SCID fragments m/z= in SCID full scan m/z= in SCID full scan m/z= in SCID full scan m/z= in SCID full scan Parent ion 11

12 Why is this relevant to HPTN?? Once type of HIV prevention trial is based on pre exposure prophylaxis (PrEP trials) In the majority of these trials, the trial subject must be HIV negative, and both the subject and partner must be ARV naïve Self report is not always reliable HPTN 052 >1,500 HIV serodiscordant couples (97% heterosexual) 13 sites in Africa, Asia, & the Americas 2 randomized groups Immediate administration of drug Delayed administration of drug (CD4 < 250) Immediate administration group say 96% reduction in risk of HIV transmission Question: were the study drugs the only drugs involved? 12

13 Antiretroviral (ARV) Screening Same chromatography protocol as for the ED drug screening study Injection of 15 standard ARV compounds to build library Screen tested on previously analyzed (SRM) ED specimens for method validation Next step: testing blinded 052 specimens Currently both US and non US specimens are being pulled for analysis ARV Screening Menu Nevirapine Saquinavir Ritonavir Atazanavir Nelfinavir Amprenavir Efavirenz Indinavir Lopinavir Tipranavir Darunavir Emtricitabine Zidovudine Tenofovir Lamivudine Stavudine 13

14 Nevirapine Saquinavir Ritonavir Atanazavir Nelfinavir Amprenavir Efavirenz Indinavir 14

15 ARV Screening Grid 15

16 ARV Screening Results SRM Analysis from the Clinical Pharmacology core designated as reference method No false negatives; 3 false positives (relative to SRM) NPV = 100%; PPV = 93% What s Next for HRMS at JHH? Pain management/rehab toxicology panel Investigation of immunoassay interferences and cross reactivity Study with Moore Clinic (HIV) examining veracity of patient self report General unknown screening?? 16

17 Menu for Pain Management/Rehab Challenges for Pain Management Support Detection of prescribed drugs the patient is supposed to be taking Detection of drugs (illicit and prescribed) the that aren t part of the treatment Clinical labs are not typically experienced in evaluating for specimen adulteration Wide distribution regarding level of understanding with respect to limitations of laboratory testing 17

18 Final Thoughts High resolution accurate mass spectrometry provides a relatively rapid approach to targeted toxicology screening An automated analyzer with an HRAMS engine could drastically change the approach to clinical toxicology in the hospital environment Acknowledgements Johns Hopkins Autumn Breaud Sabitha Schools Nkechinyere Emezienna Robert Harlan Andrew Stolbach Thermo Fisher Marta Kozak NIH U01 AI (PI: Susan Eshelman) 18

19 QUESTIONS??? 19