Best Practices for OINDP Pharmaceutical Development Programs Leachables and Extractables. VI. Special Case Compound Classes

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1 Best Practices for OINDP Pharmaceutical Development Programs Leachables and Extractables VI. Special Case Compound Classes PQRI Leachables & Extractables Working Group PQRI Training Course April 2007 Chicago, IL

2 Special Cases PAHs - Polyaromatic Hydrocarbons Also referred to as PNAs (Polynuclear Aromatics) N-Nitrosamines H 3 C N N O H 3 C 2-Mercaptobenzothiazole N S SH

3 PAHs/PNAs as Leachables in OINDP Historically, the primary source of PNAs is carbon black which is used as a filler in certain types of rubber (mostly sulfur cured). There is some potential for other PNA sources (e.g. naphthalene contamination). Some PNAs are known or suspect cancer causing agents (e.g. benzo(a)pyrene). ). FDA interest in MDIs traces back to the late 1980s. Levels of PNAs in MDIs which employ black rubber seals are typically on the order of ng to low µg/canister. The FDA historically requires that all elastomers in MDIs be evaluated and controlled for PNAs. Analytical methods typically involve GC/MS. April 2007 PQRI Training Course 3

4 PNAs Typically Analyzed and Controlled (EPA Method 610 list) Naphthalene Acenaphthylene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benzo(a)anthracene Chrysene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(e)pyrene Benzo(a)pyrene Indeno(123-cd)pyrene Dibenzo(ah)anthracene Benzo(ghi)perylene April 2007 PQRI Training Course 4

5 Structures of Some Typical PNAs naphthalene phenanthrene pyrene benzo(a)pyrene benzo(ghi)perylene

6 Trace Organic Analysis April 2007 PQRI Training Course 6

7 PNA Analysis in Rubber Possible Method Slice (or grind) a measured weight of critical rubber components. Add prepared rubber to a boiling flask with a measured volume of organic solvent (e.g. toluene). Extract via reflux for a pre-optimized time period (likely 24 hours or greater). Remove solvent and reduce in volume. Analyze by GC/MS (for example). Note that internal standards can be added at various points in the overall process. April 2007 PQRI Training Course 7

8 PNA Analysis in a Suspension Metered Dose Inhaler Drug Product - Possible Method Cool sample MDI canisters (one or several for a composite sample) over dry ice. Open canister(s) ) and filter contents to remove suspended drug particles. Note that filter assembly and catch flask must be cold. Wash filter contents with organic solvent. Evaporate sample to dryness. Dissolve residue in a measured quantity of a suitable organic solvent (e.g. toluene). Analyze by GC/MS (for example). Note that internal standards can be added at various points in the t overall process. April 2007 PQRI Training Course 8

9 April 2007 PQRI Training Course 9

10 A GC/MS System April 2007 PQRI Training Course 10

11 Reference The information summarized in the following slides related to PNA leachables studies is detailed in the following reference: Norwood, D.L., Prime, D., Downey, B.P., Creasey,, J., Sethi,, S.K., Haywood, P., Analysis of polycyclic aromatic hydrocarbons in metereds dose inhaler drug formulations by isotope dilution gas chromatography/mass spectrometry, Journal of Pharmaceutical and Biomedical Analysis,, 13(3), , April 2007 PQRI Training Course 11

12 GC/MS Analysis of Target PNAs April 2007 PQRI Training Course 12

13 EI Spectra of Pyrene and D 10 -Pyrene Note stability of the molecular ions Note the characteristic presence of doubly-charged molecular ions April 2007 PQRI Training Course 13

14 Benzo(e)pyrene and Benzo(a) pyrene April 2007 PQRI Training Course 14

15 Representation Linearity 1 and Linearity of Recovery 2 Results for a Drug Product Assay ( µg/inhaler) Target PNA Slope Intercept Correlation Naphthalene Acenaphthene Phenanthrene Fluoranthene Pyrene Benzo(e)pyrene Benzo(a)pyrene Benzo(ghi)perylene April 2007 PQRI Training Course 15

16 Limit of Detection/Quantitation Results for Selected Target PNAs Naphthalene Fluorene Phenanthrene Flouranthene Pyrene Target PNA Acenaphthylene Benzo(ghi)perylene Limit of Detection (ng/inhaler) Limit of Quantitation (ng/inhaler) April 2007 PQRI Training Course 16

17 PNA Profile of an MDI Drug Product April 2007 PQRI Training Course 17

18 PNAs as Leachables in Metered Dose Inhalers Target PNA Naphthalene Acenaphthylene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benzo(a)anthracene Chrysene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(e)pyrene Benzo(a)pyrene Dibenzo(ah)anthracene Indeno(123-cd)pyrene Benzo(ghi)perylene Total Product A (µg/inhaler) ND < ND ND ND ND 0.08 <0.05 ND ND Product B (µg/inhaler) ND ND 0.88 ND ND ND ND ND <0.025 ND ND ND Product C (µg/inhaler) ND < ND ND ND ND 0.08 <0.05 ND ND April 2007 PQRI Training Course 18

19 N-Nitrosamines Nitrosamines as Leachables in OINDP Historically, the formation of nitrosamines in rubber involves sulfur curing agents (e.g. thiurams). The issue of N-nitrosamines N in rubber goes back to late 1970s/early 1980s with concern over their presence in baby bottle rubber nipples. FDA became involved in the issue. Official analytical methods for rubber developed and validated. FDA interest in MDIs (and other OINDP) traces to the early 1990s. Levels of nitrosamines in MDIs which employ black rubber seals are typically on the order of ng/canister. The FDA historically requires that all elastomers in MDIs be evaluated and controlled for nitrosamines. Analytical methods typically involve GC with Thermal Energy Analysis detection (GC/TEA). April 2007 PQRI Training Course 19

20 Target N-nitrosamines N-nitrosodimethylamine N-nitrosodiethylamine N-nitrosodi-n-butylamine N-nitrosomorpholine N-nitrosopiperidine N-nitrosopyrrolidine O N N H 3 C N N O H 3 C O N N O O N N

21 N-nitrosamine Formation S S heat S S H N N 3 C CH CH H 3 C 3 3 S H 3 C S. N H + CS 2 H C N H. 3 C CH 3 H 3 H 3 C H 3 C N H + NOX N N O + H 3 C C H 3 HX X = NO+, N 2 O 3, N 2 O 4, NOZ (Z = Cl, Br, I, thiocyanate) April 2007 PQRI Training Course 21

22 N-nitrosamine Analysis in Rubber (AOAC Method ) Place 5g cut rubber sample in 250mL flask with 100mL methylene chloride and 100mg propyl gallate,, and hold for 17-18h. 18h. Transfer solvent and rubber sample to a Soxhlet extractor. Spike in internal standard. Extract for 1 hour. Add 100mL 5N NaOH and 2g Ba(OH) 2 to flask and carefully distill methylene chloride (discard). Continue distilling 70mL of aqueous us distillate into a separatory funnel. Add 300mg anhydrous Na 2 CO 3 to funnel, followed by 50mL methylene chloride. Extract (repeat twice more). Combine extracts in sepratory funnel. Pass through anhydrous Na 2 SO 4 (to dry), into a Kuderna_Danish apparatus (with appropriate washes). Concentrate to approximately 4mL. Remove from KD and further concentrate to 1.0mL with a nitrogen stream. Analyze by GC/TEA. April 2007 PQRI Training Course 22

23 N-nitrosamine Analysis in Rubber (AOAC Method ) Soxhlet extraction Steam distillation Extract concentration Image provided by Rubber Consultants April 2007 PQRI Training Course 23

24 Principles of Thermal Energy Analysis Detection N-nitrosamines elute from a GC column into a pyrolyzer, where they undergo pyrolysis and release nitrosyl radicals (NO. ). The pyrolysis temperature is set low enough so that nitro-compounds will not pyrolyze. Nitrosyl radicals are then oxidized with ozone in a reaction chamber to give electronically excited NO * 2. The NO * 2 decays back to ground state releasing a photon at a characteristic wavelength. This process is known as chemiluminescence chemiluminescence. Sensitivity is further increased through use of a filter- photometer for detection. April 2007 PQRI Training Course 24

25 µv Time (min) A GC/TEA System Schematic Diagram ozone pyrolysis vacuum 450 o C cold trap detector GC -130 o C N-dimethylamine N-methyletthylamine N-diethylamine Internal standard (NDIPA) N-dipropylamine N-dibutylamine N-piperidine N-pyrrolidine N-morpholine electronics April 2007 PQRI Training Course 25

26 Image provided by Rubber Consultants A GC/TEA System April 2007 PQRI Training Course 26

27 A GC/TEA System Image provided by Cardinal Health April 2007 PQRI Training Course 27

28 GC/TEA N-nitrosamines N - Separation µv N-dimethylamine N-methyletthylamine N-diethylamine Internal standard (NDIPA) N-dipropylamine N-dibutylamine N-piperidine N-pyrrolidine N-morpholine Time (min) April 2007 PQRI Training Course 28

29 GC/TEA N-nitrosamines N - Sensitivity 10 ng/ml µv N-diethylamine N-methylethylamine N-diethylamine N-dipropylamine Internal standard (NDIPA) N-dibutylamine N-piperidine N-pyrrolidine N-morpholine Time (min) April 2007 PQRI Training Course 29

30 Some Typical Limit of Detection/Quantitation Results for Target N-nitrosaminesN AOAC Method LOQs target acceptance criteria of NMT 10ppb (ng/g( ng/g) ) for an individual N-nitrosamine. N Based on the LOQs for rubber, MDI methods should target LOQs around 1 ng/canister. April 2007 PQRI Training Course 30

31 N-nitrosamines in OINDP Points to Consider N-nitrosamines are usually associated with sulfur-cured black rubber. Even with the sensitivity and selectivity of the GC/TEA, other peaks are often noted in OINDP leachables profiles. N-nitrosamines are very light sensitive, which suggests a possible procedure for identifying non-nitrosamine nitrosamine GC/TEA peaks. April 2007 PQRI Training Course 31

32 Analysis of Mercaptobenzothiazole (MBT) Compounds from Sulfur Cured Rubber by a Liquid Chromatography Tandem Mass Spectrometry (LC-MS-MS) Method Tianjing Deng*, Shuang Li, Xiaoya Ding and Song Klapoetke PPD 8551 Research Way Middleton, WI * Corresponding author April 2007 PQRI Training Course 32

33 Mercaptobenzothiazole (MBT) and other benzothiazoles are common vulcanization accelerators for rubber materials that are used in pharmaceutical container/systems, such as the gaskets in the pressurized Metered-Dose Inhaler (pmdi). MBT is of particular concern since it is considered a potential carcinogen and has been shown to migrate into drug formulations. Due to the toxicological concern and leachability of MBT and other benzothiazoles, analytical methods have been developed to study these types of compounds in the fields of food additives and contaminants (1), contact dermatitis caused by the rubbers (2), as well as pharmaceutical packaging systems (3). MBT can be analyzed by gas chromatography (4) but many other benzothiazoles are thermally-labile and readily decomposed in the GC inlet. HPLC methods are commonly used to study April 2007 PQRI Training Course 33

34 N S SH N S S S N S MBT MBTS In this study, a method using liquid chromatography with tandem mass spectrometer (LC-MS-MS) was developed to analyze MBT in the sulfur cured rubber. The method is capable of detecting ng level of MBT in the rubber extracts. This study demonstrates the feasibility of using detector with high selectivity, such as LC-MS-MS method, for extractable/leachable with special toxicological concern that requires greater sensitivity and specificity. April 2007 PQRI Training Course 34

35 References: Barnes, K.A., Castle L., Damant, A. P., Read, W. A., and Speck, D. R., Food Additives and Contaminants, Vol. 20, No. 2, (2003). Hansson, C., Bergendorff, O., Ezzelarab, M., and Sterner, O., Contact Dermatitis, 36, , (1997). Gaind, V. S., and Jedrzejczak, K., Journal of Analytical Toxicology, Vol. 17, 34-37, (1993). Niessen, W. M. A., McCarney, C. C., Moult, P. E.G., Tjaden, U. R., and Van der Greef, J., Journal of Chromatography, 647, , (1993). Mathieu, C., Herbreteau, B., Lafosse, M., Morin, Ph., Renaud, M., Cardinet, C., and Dreux, M., J. High Resol. Chromatogr., 23, (9), , (2000). April 2007 PQRI Training Course 35

36 Method Conditions: HPLC Parameters Mobile Phase: Water:Methanol:Formic acid 20:80:0.05 (v/v/v) Flow Rate: 0.2 ml/min Column: Waters Symmetry C18, 3.5 µm, 2 x 100 mm Column Temperature: 40 C Autosampler Temperature: Ambient Injector Volume: 5 µl April 2007 PQRI Training Course 36

37 Bench-top LC/MS Systems Time-of-flight Linear ion trap Triple Quadrupole April 2007 PQRI Training Course 37

38 Triple Quadrupole Mass Spectrometer April 2007 PQRI Training Course 38

39 MS-MS Spectrum of MBT +Product (168.0): 64 MCA scans from Sample 1 (direct) of MBT2.wiff Max. 1.4e7 cps. 1.4e7 1.3e e7 1.1e7 1.0e7 9.0e6 8.0e6 7.0e6 N S SH Mercaptobenzothiazole (MBT) e e6 4.0e6 3.0e e e m/z, amu April 2007 PQRI Training Course 39

40 MS-MS Spectrum of MBTS +Product (333.0): 84 MCA scans from Sample 2 (MBTs) of MBT2.wiff 5.5e N S S Max. 5.6e5 cps. 5.0e5 S N 4.5e5 4.0e5 3.5e5 S Dibenzothiazyl Disulfide (MBTS) 3.0e5 2.5e5 2.0e5 1.5e5 1.0e5 5.0e m/z, amu April 2007 PQRI Training Course 40

41 Mass Spectrometer: PE Sciex API 2000/API365 Triple Quadruple Mass Spectrometer Ionization Mode: Detection Mode: Positive ElectroSpray MRM m/z 168/ /167 April 2007 PQRI Training Course 41

42 Selectivity/Specificity Time (min) MRM Chromatogram of Extraction Blank: MBT (blue trace) and MBTS (red trace) April 2007 PQRI Training Course 42

43 MRM Chromatograms of MBT (blue) and MBTS (red) in the 500 ng/ml standard solution. XIC of +MRM (2 pairs): 168.0/135.0 amu from Sample 5 (STD-NF) of DataSET2.wiff Max. 5.7e4 cps. 5.7e e4 MBT 5.0e4 4.5e4 4.0e4 3.5e4 3.0e4 2.5e4 2.0e4 MBTS 1.5e4 1.0e Time, min April 2007 PQRI Training Course 43

44 MRM Chromatograms of MBT (blue) and MBTS (red) in the 30 min TBME Extract. XIC of +MRM (2 pairs): 168.0/135.0 amu from Sample 22 (30min-1) of DataSET1.wiff Max. 8.9e4 cps. 8.9e4 8.5e e4 7.5e4 7.0e4 6.5e4 6.0e4 5.5e4 5.0e4 4.5e4 4.0e4 3.5e4 3.0e4 2.5e4 2.0e4 1.5e4 1.0e Time, min April 2007 PQRI Training Course 44

45 Extraction Method Hansson et al. studied the extraction of MBT/MBTS using different solvents. They found out that Methyl tert-butyl Ether (MTBE) is a good solvent for MBT/MBTS due to its: Powerful extraction medium Low toxicity Inertness to MBT/MBTS High volatility In this study, the rubber was cut into 3 x 3 mm squares. One gram of the rubber was extracted with 10 ml MTBE for 30 minutes by sonication. After extraction, the extract was diluted to different volume using Methanol: Water 50: 50 diluent to give varying MBT concentrations and filtered using glass fiber syringe filters for LC- MS study. April 2007 PQRI Training Course 45

46 The Extraction Study of MBT by MTBE from Sulfur-Cured Rubber Extractaed MBT (ppm) Extraction Time April 2007 PQRI Training Course 46

47 Linearity Plot of MBT ( ng/ml) Response MBT MBTS Concentration (ng/ml) April 2007 PQRI Training Course 47

48 Repeatability Calculated MBT Concentration (PPM) in Three Replicates of Extract. Calculated Concentration (PPM) Mean %RSD (n=3) Replicate 1 Replicate 2 Replicate April 2007 PQRI Training Course 48

49 LOQ/LOD The DL of MBT was calculated using S/N ratio = 3. DL = 6 ng/ml in the solution or 12 pg on column. M BT Time (min) MRM Chromatogram of MBT Standard (50 ng/ml) April 2007 PQRI Training Course 49

50 Accuracy - Filter Study A Filter study was conducted to verify that the syringe filter used in the sample preparation did not reduce the recovery of MBT and MBTS. Three 500 ng/ml standards were analyzed before and after the filtration and the area responses of MBT and MBTS were compared. The percent differences between the filter and nonfiltered samples are less than 2.5% indicating that filtration does not affect the method accuracy. Compounds Mean area responses MBT MBTS Before Filtration After Filtration % Difference April 2007 PQRI Training Course 50

51 Accuracy- MBT Recovery Approximately 360 ng/ml of MBT was spiked into the extract. The sample was prepared using the sample preparation procedure and analyzed. Three replicates of spiking samples were prepared and analyzed. The mean recovery ofmbt was 87.3% Recovery Results of MBT Calculated Extract (ng/ml) Replicate 1 (ng/ml) Replicate 2 (ng/ml) Replicate 3 (ng/ml) %RSD 3.5 (n=7) %Recovery NA April 2007 PQRI Training Course 51

52 Summary Points The developed LC/MS/MS method looks good for MBT, and potentially MBTS. MBTS was demonstrated to hydrolyze under the extraction conditions selected, forming more MBT. This method requires full optimization and validation. April 2007 PQRI Training Course 52

53 Analytical Method Validation System suitability Chromatographic parameters (e.g. resolution, tailing) Injection precision Precision Repeatability Intermediate Precision Selectivity Accuracy (three spiking levels) Linearity/Range LOD/LOQ Robustness (e.g. column, mobile phase, temperatures, MS parameters) April 2007 PQRI Training Course 53

54 Concluding Points Special Case compounds require dedicated and highly specific analytical methods. Dedicated and highly specific analytical methods have been developed for all special case compounds and compound classes. April 2007 PQRI Training Course 54