Inductively coupled plasma mass spectrometry

Transcription

1 Slotervaart Hospital Inductively coupled plasma mass spectrometry A unique, ultrasensitive method for exploring the pharmacology of metal-based anticancer agents Inductief gekoppelde plasma-massaspectrometrie een uniek, zeer gevoelig hulpmiddel voor het onderzoeken van de farmacologie van metaal bevattende antikanker middelen Elke Brouwers, PharmD PhD October 2008

2 Slotervaart Hospital / NKI-AVL Department of pharmacy & pharmacology Slotervaart Hospital NKI-AVL -Introduction -

3 This presentation Introduction on metal-based anticancer agents Mechanism of action Pharmacokinetics and pharmacodynamics Bioanalytical analysis Introduction on ICP-MS ICP-MS in oncology Method development Validation Clinical studies Conclusions -Introduction -

4 Metal-based anticancer agents (1) Heavy metals toxic to human Toxic effects can be positively used in cancer treatment Metal-containing anticancer agent discovered in 1960s Coordination complexes H 3 N H 3 N Pt Cl Cl Cis-diamminedichloridoplatinum(II) = Cisplatin -Introduction -

5 Metal-based anticancer agents (2) H 3 N N H 3 Pt Cl Cl Blood stream [Cl - ] = 100 mmol/dm 3 Distribution H 3 N H 3 N Uptake tissue Pt Uptake/binding blood components Elimination Cl Cl RNA Hydrolysis [Cl - ] = 4 mmol/dm 3 H 3 N H 3 N S-donors Pt OH 2 + Cl White blood cells Red blood cells Proteins Small molecules Cell nucleus DNA Uptake Cell -Introduction -

6 Metal-based anticancer agents (3) Formation of Pt-DNA adducts 3 % X H 3 N Pt NH 3 G G G NH 3 Pt NH % G G G NH 3 1 % Pt N Pt 10 % H 3 N NH 3 NH G 3 H 3 N Pt NH 3 G G A Pt NH 3 NH % -Introduction -

7 Metal-based anticancer agents (4) Use cisplatin is hampered by side effects Ototoxicity Nephrotoxicity Neurotoxicity New platinum-based drugs Carboplatin Oxaliplatin New ruthenium-based drugs NAMI-A KP1019 -Introduction -

8 Pharmacokinetics and -dynamics Pharmacokinetics How does the body affect the drug What happens to the drug after infusion Distribution of drug Elimination of drug Pharmacodynamics How does the drug affect the body Formation of Pt-DNA adducts Cytotoxic effect Side effects -Introduction -

9 Bioanalytical analysis Requirements of analytical method for metals in oncology Low detection limits Simple sample pretreatment Reliable Limitations for analysis of metal-based anticancer agents Rapid biotransformation Highly active metabolites Research kinetics and dynamics of intact compound and metabolites is technically difficult So: determination of metal element -Introduction -

10 Elemental analysis in oncology Biological fluids Plasma: free and protein bound metal fraction Plasma ultrafiltrate (puf): includes free metal fraction Urine Saliva Cells Metal DNA adducts and protein adducts Environmental samples Air samples Wipe samples (swaps) -Introduction -

11 Elemental analysis in oncology Biological fluids Plasma: free and protein bound metal fraction Plasma ultrafiltrate (puf): includes free metal fraction Urine Saliva Cells Metal DNA adducts and protein adducts Environmental samples Air samples Wipe samples (swaps) -Introduction -

12 ICP-MS (1) ICP : Inductively Coupled Plasma: Ion Source Molecules Atoms Ions MS: Mass Spectrometer : Filter Ions separation as a function of mass/charge ratio Signal proportional to number of ions -Introduction -

13 ICP-MS (2) -Introduction -

14 ICP-MS (3) -Introduction -

15 ICP-MS (4) Water Environment Rocks, sludges, sediments, soils, plants, fertilizers Wastes (Petro)chemical industry Pharmaceuticals Biological Blood, serum, urine, proteins, DNA etc. -Introduction -

16 Sample pretreatment (1) Analysis of platinum and ruthenium Elemental interferences Online correction Doubly charged interferences Minimising formation doubly charged No problem with platinum Polyatomic interferences Minimising oxide formation Monitoring e.g. hafnium background Monitoring isotope ratios -Method development -

17 Sample pretreatment (2) Matrix interferences Dilution matrix in appropriate solvent When necessary digestion matrix Externalcalibration with matrix matched samples Internal standardisation (iridium and yttrium) -Method development -

18 Sample pretreatment (3) -Method development -

19 Sample pretreatment (4) Biological fluids Plasma: dilution EDTA/triton puf: dilution 1% nitric acid Urine: dilution 1% nitric acid Platinum-DNA adducts Digestion DNA in 1% nitric acid at 70 C Environmental samples Extraction of swaps Filtration Dilution 1% hydrochloric acid -Method development -

20 Validation parameters (1) FDA guidelines for bioanalytical method validation Determination of limit of quantification Carry-over Linearity Specificity Accuracy Precision Crossanalyte/internal standard interference Stability -Validation -

21 Validation parameters (2) Limit of quantification for platinum In final samples: ng Pt /L Plasma: 20 ng/l puf: 7.5 ng/l Platinum-DNA adducts: 0.75 pg Pt (7.5 fg / µg DNA when using 100 µg DNA Environmental samples: 5 pg Pt per wipe sample (0.05 pg / cm 2 when wiping 100 cm 2 ) -Validation -

22 Clinical applications Short-term pharmacokinetics Knowledge on distribution/elimination of drug Long-term pharmacokinetics Knowledge on retention of drug Association with persistent side effects Pharmacodynamics Knowledge onpt-dnaadduct levels Association with effect and side effects Environmental monitoring Knowledge on spread of drugs in preparation units -Clinical studies -

23 Clinical applications Short-term pharmacokinetics Knowledge on distribution/elimination of drug Long-term pharmacokinetics Knowledge on retention of drug Association with persistent side effects Pharmacodynamics Knowledge onpt-dnaadduct levels Association with effect and side effects Environmental monitoring Knowledge on spread of drugs in preparation units -Clinical studies -

24 Long-term pharmacokinetics (1) Platinum agents have led to improved life expectancy Long-term side effects relevant Neuropathy Nephrotoxicity Ototoxicity Secondary malignancies Investigation of long-term pharmacokinetics, distribution, and elimination Platinum retention in plasma and puf studied 8-75 months after therapy with cisplatin or oxaliplatin -Clinical studies -

25 Long-term pharmacokinetics (2) What do we want to know? Platinum retention in patients after treatment Analytical challenges: Platinum levels of sample pretreatment devices and solvents Platinum background of human samples due to factors other than chemotherapy treatment Therefore: Thorough optimisation of pretreatment Analysis of control plasma -Clinical studies -

26 Long-term pharmacokinetics (3) Platinum concentration (ng/l) LLOQ plasma 0.1 Plasma of healthy controls Plasma of cancer control patients Plasma of cancer patients treated with cisplatin puf of cancer patients treated with cisplatin Plasma of cancer patients treated with oxaliplatin puf of cancer patients treated with oxaliplatin -Clinical studies -

27 Long-term pharmacokinetics (4) 3500 Plasma platinum concentration (ng/l) Cisplatin Oxaliplatin Time since end treatment (months) -Clinical studies -

28 Pharmacodynamics (1) What do we want to know? What happens to tumour tissue? Do platinum-dna adduct levels predict treatment outcome? Analytical challenges: Difficult to obtain (tumour) tissue White blood cell levels as a surrogate measure Therefore: Develop a method that only needs a small amount of tissue -Clinical studies -

29 Pharmacodynamics (2) Amount of tissue (mg) Average amount of DNA (µg) Patient 1 pg Pt/µg DNA Patient 2 pg Pt/µg DNA Patient 3 pg Pt/µg DNA Tissue Normal Tumour Normal Tumour Normal Tumour Mean tissue Precision (RSD (%), n=4) WBC Ratio tissue to WBC level Clinical studies -

30 Environmental monitoring (1) Occupational exposureis potentialhealth hazard Pharmacy technicians, nurses, cleaners Workplace contamination Contaminations packaging Detection of cytotoxic agents in blood and urine Relationship between exposure and harmful effects difficult to establish Aim for lowest contaminationas achievable -Clinical studies -

31 Environmental monitoring (2) What do we want to know? Contamination of production units of hospital pharmacies Analytical challenges: Background platinum levels Develop a suitable method for wipe sampling Goal: Identification of main exposure routes Assessment of effectiveness of cleaning and working procedures Increase of consciousness among personnel -Clinical studies -

32 Environmental monitoring (3) -Clinical studies -

33 Environmental monitoring (4) -Clinical studies -

34 Conclusions ICP-MS is a unique, ultrasensitive tool for exploring the pharmacology of metal-based anticancer agents In addition, ICP-MS is very suitable for exploring the occupational exposure to metal-containing anticancer agents -Conclusions -

35 Aknowledgements Slotervaart Hospital Jos Beijnen Matthijs Tibben Alwin Huitema Hilde Rosing Michel Hillebrand NKI-AVL Jan Schellens Dick Pluim Willem Boogerd Physicians Patients The Netherlands Organisation for Health Research and Development ZonMw -Aknowledgements -