Development of a Bioanalytical Method for the Simultaneous
Transcription
Development of a Bioanalytical Method for the Simultaneous
Development of a Bioanalytical Method for the Simultaneous Quantification of Synthetic Insulin Analogs in Human Plasma: Challenges of Working with Large Peptides Erin E. Chambers and Kenneth J. Fountain Waters Corporation ©2012 Waters Corporation 1 Acknowledgement Erin Chambers ©2012 Waters Corporation 2 Outline Background Mass Spectrometry Liquid Chromatography Solid Phase Extraction and Plasma Data ©2012 Waters Corporation 3 Background Why bioanalysis for insulin analogs? 1. Many coming off patent between 2013 and 2015 o Bioequivalence studies 2. Methods needed to identify/differentiate specific insulins o Forensic toxicology, cases of wrongful death o Anti-doping o Understanding/monitoring of patient dosing? Current analytical methods 1. ELISA- based assays 2. Nano-flow or low flow LC-MS/MS assays 3. SPE-immuno affinity LC-MS/MS assays 4. Assays where insulin has been digested or disulfide bonds reduced ©2012 Waters Corporation 4 Why LC-MS/MS? Why an LC-MS/MS based assay? — ELISA assays can not differentiate between human insulin and analogs — Challenges with ELISA assays o time consuming, expensive to develop o require separate assay for each peptide o limited linear dynamic range o Possible cross reactivity Benefits of LC-MS/MS — LCMSMS provides single assay for multiple insulin analogs — Broad linear dynamic range — Accurate, precise — Universal — Faster, cheaper method development ©2012 Waters Corporation 5 Insulin and Analogs Human Insulin MW 5808 Insulin A Chain Insulin B Chain Insulin glargine (Lantus®) Avg MW 6063 Insulin aspart (Novalog®) Avg MW 5826 Insulin A Chain Insulin A Chain Insulin B Chain Insulin B Chain Insulin detemir (Levemir®) Avg MW 5917 ©2012 Waters Corporation Insulin A Chain Insulin A Chain Insulin B Chain Insulin B Chain Insulin glulisine (Apidra®) Avg MW 5823 Slide courtesy of Martha Stapels6 Specific Challenges in Developing an LC-MS/MS Assay for Insulin Analogs Specificity in matrix High level of non-specific binding (NSB) Aggregation Low MS sensitivity — Poor fragmentation — Multiple precursors Chromatographic peak shape Protein binding ©2012 Waters Corporation 7 Outline Background Mass Spectrometry Liquid Chromatography Solid Phase Extraction and Plasma Data ©2012 Waters Corporation 8 Influence of Flow Rate on Specific Precursor Formation During Tuning Human Insulin 1162.3542 100 1162.34031162.5503 1: TOF MS ES+ 4.91e4 5+ TOF MS ES+ 1.16e5 1452.6415 1452.8917 100 1452.3910 1162.15121162.7603 1453.1422 % 1453.3927 1162.9493 % 200 µL/min 1452.1406 1161.9482 1453.6432 1163.1523 1453.8936 1451.8903 1129.9305 1107.3191 0 1000 1100 1454.3947 0 1452 1453 1300 1400 1500 1452.8917 100 1600 1700 1800 % 5+ 2.1 x 50 mm, 1.7 µm 3+ 1453.3927 1162.3069 1452.1406 1936.5212 1936.8464 1453.6432 1458.3903 1458.6412 1162.9159 1936.1780 1937.1898 1110.7625 1163.3151 ©2012 Waters Corporation 1100 1166.9028 1200 1262.7163 1300 1937.5151 1935.8528 1943.8459 1458.8763 1163.1189 1246.7325 1104.7563 m/z TOF MS ES+ 1.16e5 4+ 1162.7130 1162.1110 0 1000 1455 m/z 1900 1452.3910 1453.1422 10 µL/min 1454 1452.6947 1452.4286 1453.1798 1452.1938 1458.4440 1167.3573 1167.5537 1200 1454.1284 4+ 1163.3553 1161.7524 1166.7542 1451.8903 1459.1431 1382.7155 1463.6321 1518.6868 1400 1500 1944.5157 1944.8418 1935.5095 1951.1663 1958.4913 1600 1700 1800 1900 m/z 9 MS scan of Insulin Glargine 7+ Scan ES+ 3.47e7 867.27 100 8+ 6+ 759.06 1011.73 % 197.03 256.09 181.02 279.23 304.11 5+ 527.34 387.32 0 100 637.36 764.32 874.98 1020.66 1213.76 m/z 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 Lantus infused at 10 µL/min teed into LC effluent containing 40% ACN ©2012 Waters Corporation 10 MSMS of m/z 867 7+ Insulin Glargine Precursor Collision Energy = 18 eV Collision Energy = 35 eV ©2012 Waters Corporation 11 Immonium Ions: high intensity, however… ©2012 Waters Corporation 12 Avoiding Immonium Ion Fragments 02-Mar-2012 1: MRM of 4 Channels ES+ 867 > 136 (Lantus) 9.40e5 0.99 100 1.68 % 867 -> 136 (tyrosine immonium ion) 1.58 1.15 Lack of Specificity 1.20 1.30 1.40 1.49 0.56 0 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.20 2.40 2.60 2.80 3.00 2.60 2.80 3.00 0.99 100 3.20 3.40 1: MRM of 4 Channels ES+ 867 > 984 (Lantus) 8.97e5 867 -> 984 % 0 2.00 0.20 ©2012 Waters Corporation 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 3.20 3.40 Time 13 Fragmentation Patterns for Insulin Analogs 1369.6 1161.2 1164.8 1369.0 1370.3 1160.5 1425.9 1165.7 1343.8 1140.7 1427.1 1524.5 % 100 346.1 347.0 446.9 849.6 0 400 600 960.6 800 1000 1200 1400 971.8 100 % 970.8 660.7 464.4 0 600 800 1090.2 1132.8 1263.5 m/z 1800 1403.5 1000 1200 1400 866.7 867.3 855.9 539.2 1600 1800 Insulin Glargine MSMS of 867 7+ % 100 400 1737.9 m/z 400 0 1600 1688.9 Insulin Aspart MSMS of 972 6+ 972.0 893.8 Insulin Glulisine MSMS of 1165 5+ 984.0 1170.6 600 800 1000 1200 m/z 1400 1600 1800 1180.3 % 100 1184.1 1366.0 Insulin Detemir MSMS of 1184 5+ 454.3 0 m/z 400 ©2012 Waters Corporation 600 800 1000 1200 1400 1600 1800 14 MS conditions for Insulin Analogs MS system: Xevo TQ-S triple quadrupole — Capillary: 3.00 kV — Desolvation temperature: 600 °C — Desolvation flow: 1000 L/hr — Dwell time 0.025 sec per transition Specific Insulin MRM Transition Glargine 867->984 1011->1179 Detemir 1184-> 454.4 1184-> 1366.3 Aspart 971.8 -> 660.8 971.8 -> 1139.4 Glulisine 1165 -> 346.2 1165 -> 1370 Bovine (IS) 1147.5 -> 315 ©2012 Waters Corporation Cone Collision Voltage (V) Energy (eV) 60 18 60 25 60 20 60 20 60 18 12 18 14 22 14 22 50 35 15 Outline Background Mass Spectrometry Liquid Chromatography Solid Phase Extraction and Plasma Data ©2012 Waters Corporation 16 Predicted Van Deemter Using Flow Rate: Influence of Analyte Size on Optimal Flow Rate Range Plate Height vs. flow Rate 3.5 µm particle 60 MW 300 MW 1000 Dm m2/sec = 1.4 e-10 MW 2500 50 MW 4500 40 Dm m2/sec = 1.99 e-10 H (um) 2.1 x 50 mm 30 Dm m2/sec = 3.46 e-10 20 Dm m2/sec = 7.12 e-10 10 0 0 0.1 0.2 0.3 0.4 0.5 Flow rate (mL/min) ©2012 Waters Corporation 17 Predicted Van Deemter Using Flow Rate: Influence of Chromatographic Particle Size 45 Plate Height vs. Flow Rate 3.5 um 2500 MW Peptide 40 1.7 um 35 H (um) 30 25 2.1 x 50 mm 20 15 10 5 0 0 0.1 0.2 0.3 0.4 0.5 Flow rate (mL/min) Gilar et al, Journal of separation science 2005, 28, 1694 ©2012 Waters Corporation 18 Chromatographic Peak Shape Using Formic Acid Mobile Phase Bovine Insulin MW 5734 1147.5 > 315.2 1.46 100 % ACQUITY UPLC BEH300 C18 1.7 µm 2.1 X 50mm Peak Width 11 sec 0 0.20 0.40 0.60 0.80 1.00 1.20 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 1.29 100 % 1.40 ACQUITY UPLC CSH C18 1.7 µm 2.1 X 50mm Peak Width 3.6 sec 0 Time 0.20 ©2012 Waters Corporation 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 19 Alternative Column for Peptide Analysis: Charged Surface Hybrid (CSH™) C18 1147.5 > 315.2 1.46 100 % ACQUITY UPLC BEH300 C18 1.7 µm 2.1 X 50mm Peak Width 11 sec 0 0.20 0.40 0.60 0.80 1.00 1.20 100 % 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 1.29 ACQUITY UPLC CSH C18 1.7 µm 2.1 X 50mm Peak Width 3.6 sec 0 Time 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 Bovine Insulin, IS MW 5734 ©2012 Waters Corporation 20 Lesson Learned: Column Conditioning MRM of 10 Channels ES+ 866.8 > 984 (Lantus) 2.85e6 100 % After 9 injections of precipitated plasma 0 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 100 2nd injection after solvent blanks % 0 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 100 3.00 3.25 MRM of 10 Channels ES+ 866.8 > 984 (Lantus) 2.85e6 New column:1st injection after solvent blanks % 0 0.00 3.00 3.25 MRM of 10 Channels ES+ 866.8 > 984 (Lantus) 2.85e6 0.25 ©2012 Waters Corporation 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 Time 21 UPLC conditions for Synthetic Insulin Analogs Instrument: ACQUITY UPLC I-Class with FTN or ACQUITY Column: ACQUITY CSH™ C18 2.1 X 50mm, 1.7 µm Mobile Phase A: 0.1% formic acid in water Mobile Phase B: 0.1% formic acid in acetonitrile Weak wash: mobile phase A Strong wash: 50/25/24/1 ACN/IPA/water/formic acid Flow rate: 0.25 mL/min Column temperature: 60° C Sample Manager temperature: 15° C Gradient: 20% B to 65% B in 2 min, to 98% B at 2.1 min, hold for 0.5 min, return to initial at 2.7 min Total cycle time: 3.5 min Injection volume: 15 µL ©2012 Waters Corporation 22 Separation of 4 Synthetic Insulins and the Internal Standard, Bovine Insulin MRM of 8 Channels ES+ 1.22 100 1.11e5 Bovine (IS) Aspart % Glargine s MRM of 8 Channels ES+ 1.22 100 1.11e5 Glulisine Detemir 2.95 1.45 1.55 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 Time % 0 0.00 1.45 1.54 1.55 0 1.05 ©2012 Waters Corporation 1.10 1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 Time 23 Detection Limit for Insulin Glargine in Solvent Standards MRM of 4 Channels ES+ 867 > 984 (Lantus) 2.35e4 Area 1.01 663 100 % 100 pg/mL 0 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 1.25 MRM of 4 Channels ES+ 867 > 984 (Lantus) 2.35e4 Area 100 1.01 459 % 50 pg/mL 0 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 1.25 MRM of 4 Channels ES+ 867 > 984 (Lantus) 2.35e4 Area 0.90 0.95 1.00 1.05 1.10 1.15 1.20 100 % Solvent Blank 0 Time 0.75 ©2012 Waters Corporation 0.80 0.85 1.25 24 Linearity for Insulin Glargine in solvent Standards: 50 pg/mL to 50 ng/mL % Dev 3.4 -7.2 1.5 -4.4 10.1 7.2 3.4 -0.1 -13.9 ©2012 Waters Corporation 25 Insulin Analogs: Testing for and Eliminating Non-Specific Binding insulin glargine solution: <30 min on benchtop 1: MRM of 4 Channels ES+ 1011.2 > 1179 (Lantus) 1.01 469 100 Area % 30% MeOH, 10% acetic acid, 0.05% rat plasma 0 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 100 2.60 2.80 3.00 1: MRM of 4 Channels ES+ 1011.2 > 1179 (Lantus) Area % 30% MeOH, 10% acetic acid 0 0.20 ©2012 Waters Corporation 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 Time 3.00 26 Outline Background Mass Spectrometry Liquid Chromatography Solid Phase Extraction and Plasma Data ©2012 Waters Corporation 27 Extraction Conditions for Insulin Analogs from Human Plasma Oasis® HLB µElution 96-well plate Condition: 200 µL methanol Equilibrate: 200 µL water Load Sample: 300 µL human plasma diluted with 300 µL 10mM TRIS Base Wash: 200 µL 5% methanol, 1% acetic acid in water Elute: 2X 25 µL 60% methanol, 10% acetic acid in water Inject 15 µL ©2012 Waters Corporation 28 Extraction from Human Plasma: Impact of Pretreatment Prior to SPE Final Eluate 100 % 1: MRM of 4 Channels ES+ TIC 4.48 TRIS Base dilution 2.86 3.95 4.59 5.50 6.30 7.12 8.21 0 1.00 2.00 3.00 4.00 5.00 7.00 5.76 100 % 6.00 TFA dilution 8.00 9.00 1: MRM of 4 Channels ES+ TIC 4.46 2.88 3.92 8.00 4.56 8.51 0 1.00 2.00 3.00 4.00 5.00 6.00 7.00 % 100 145.0 118689384 146.9 70124136 259.1 43548620 8.00 9.00 2: MS2 ES+ 334.8 134193152 357.1 115938712 371.1 55654400 443.0 681.2 35474636 24706662 570.2;13623731 911.2 981.4 31676710 32655092 1063.1 21816462 % 0 m/z 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 2: MS2 ES+ 100 Human Serum Albumin 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 ©2012 Waters Corporation m/z 29 LOD and LLOQ for Insulin Glargine in Human Plasma 1: MRM of 3 Channels ES+ 867 > 984 (Lantus) 1.87e5 1.02 100 % 0.5 ng/mL Lantus 0 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 1: MRM of 3 Channels ES+ 867 > 984 (Lantus) 1.87e5 2.40 2.60 2.80 3.00 3.20 3.40 1: MRM of 3 Channels ES+ 867 > 984 (Lantus) 1.87e5 2.40 2.60 2.80 3.00 100 1.02 % 0.2 ng/mL Lantus 0 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 100 % Blank human plasma 0 0.20 ©2012 Waters Corporation 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 3.20 3.40 Time 30 LOD and LLOQ for Insulin Detemir in Human Plasma 100 0.5 ng/mL Levemir % 1.56 1196 MRM of 3 Channels ES+ 1183.96 > 454.404 (Levemir) 6.16e4 Area 0 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 100 0.2 ng/mL Levemir % 1.56 760 3.20 3.40 MRM of 3 Channels ES+ 1183.96 > 454.404 (Levemir) 5.34e4 Area 0 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 100 Blank human plasma 1.57 261 % 0 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 3.20 3.40 MRM of 3 Channels ES+ 1183.96 > 454.404 (Levemir) 5.47e4 Area 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 Time 20 µL injected ©2012 Waters Corporation 31 LOD and LLOQ for Insulin Glulisine in Human Plasma MRM of 3 Channels ES+ 1165.032 > 1369.904 (Apidra) 2.58e5 Area 1.08 8650 100 % 0.5 ng/mL Apidra 0 0.20 0.40 0.60 0.80 100 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.60 2.80 1.08 2786 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 100 3.20 3.40 MRM of 3 Channels ES+ 1165.032 > 1369.904 (Apidra) 9.83e4 Area 3.00 3.20 3.40 MRM of 3 Channels ES+ 1165.032 > 1369.904 (Apidra) 9.66e4 Area Blank human plasma % 0 3.00 0.2 ng/mL Apidra % 0 2.40 0.20 ©2012 Waters Corporation 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 Time 32 LOD and LLOQ for Insulin Aspart in Human Plasma 1ngmL_110111_001 Sm (SG, 1x3) 100 1.08 439 % 1 ng/mL Novolog MRM of 4 Channels ES+ 971.8 > 660.8 (Novolog) 1.44e4 Area 0 0.20 0.40 0.60 0.80 500pgmL_110111_001 Sm (SG, 1x3) 100 1.00 1.20 1.40 1.60 1.80 2.00 1.08 263 0.20 0.40 0.60 0.80 blank_plasma_110111_001 Sm (SG, 1x3) 100 1.00 1.20 1.40 1.60 1.80 2.00 2.60 2.80 3.00 3.20 3.40 MRM of 4 Channels ES+ 971.8 > 660.8 (Novolog) 1.44e4 Area 2.20 2.40 2.60 2.80 3.00 3.20 3.40 MRM of 4 Channels ES+ 971.8 > 660.8 (Novolog) 1.44e4 Area Blank human plasma % 0 2.40 0.5 ng/mL Novolog % 0 2.20 0.20 ©2012 Waters Corporation 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 Time 33 Linearity for Insulin Detemir and Glulisine in Human Plasma Insulin Detemir R2= 0.997 Linear fit, 1/x weighting Compound name: Levemir Correlation coefficient: r = 0.998386, r^2 = 0.996775 Calibration curve: 0.0763365 * x + -0.00621954 Response type: Internal Std ( Ref 2 ), Area * ( IS Conc. / IS Area ) Curve type: Linear, Origin: Exclude, Weighting: 1/x, Axis trans: None Residual 10.0 0.0 -10.0 Response ng/mL 1.50 1.00 0.50 0.00 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 Insulin Glulisine R2= 0.998 Linear fit, 1/x weighting ng/mL 18.0 name:20.0 22.0 24.0 Compound Apidra Correlation coefficient: r = 0.998910, r^2 = 0.997822 Calibration curve: 0.141619 * x + -0.0172456 Response type: Internal Std ( Ref 2 ), Area * ( IS Conc. / IS Area ) Curve type: Linear, Origin: Exclude, Weighting: 1/x, Axis trans: None Residual 5.0 0.0 -5.0 -10.0 ng/mL Response 3.00 2.00 1.00 0.00 0.0 ©2012 Waters Corporation ng/mL 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 34 Standard Curve and QC Samples: Insulin Detemir in Human Plasma Name Blank plasma 200 pg/mL plasma 500 pg/mL plasma 1 ng/mL plasma 5 ng/mL plasma 10 ng/mL plasma 25 ng/mL plasma QC 350 pg/mL plasma QC 750 pg/mL plasma QC 2 ng/mL plasma QC 8 ng/mL plasma QC 20 ng/mL plasma ©2012 Waters Corporation Conc ng/mL Area Response IS Area %Dev 31.523 0.2 153.33 0.012 13239.484 16.6 0.5 375.641 0.03 12437.347 ‐4.6 1 750.185 0.06 12419.075 ‐12.7 5 4714.479 0.399 11801.818 6.3 10 8984.796 0.696 12907.325 ‐8 25 25007.11 1.948 12836.323 2.4 0.35 241.626 0.75 733.632 2 1969.438 8 7486.715 20 20549.63 0.02 12200.732 0.058 12560.556 0.141 13954.36 0.615 12168.7 1.616 12712.905 ‐2.6 12.9 ‐3.5 1.8 6.3 Calc Conc ng/mL 0.233 0.477 0.873 5.314 9.2 25.602 0.341 0.847 1.93 8.141 21.257 35 Standard Curve and QC Samples: Insulin Glulisine in Human Plasma Name Blank plasma 200 pg/mL plasma 500 pg/mL plasma 1 ng/mL plasma 5 ng/mL plasma 10 ng/mL plasma 25 ng/mL plasma QC 350 pg/mL plasma QC 750 pg/mL plasma QC 2 ng/mL plasma QC 8 ng/mL plasma QC 20 ng/mL plasma ©2012 Waters Corporation Conc ng/mL Area Response IS Area %Dev Calc Conc ng/mL 0.2 0.5 1 5 10 25 36.883 230.286 1017.418 2067.989 11329.985 23803.182 57342.039 0.013 0.057 0.12 0.61 1.396 3.606 17486.813 17807.012 17249.779 18563.846 17051.553 15903.752 7.4 5 ‐3.2 ‐11.4 ‐0.2 2.3 0.215 0.525 0.968 4.431 9.979 25.581 0.35 0.75 2 8 20 626.093 1700.371 4744.934 18609.773 47779.25 0.035 0.101 0.31 1.013 2.828 17654.807 16856.465 15316.951 18366.383 16894.605 6.3 11.2 15.5 ‐9 0.5 0.372 0.834 2.309 7.277 20.091 36 Conclusions Importance of: column chemistry, sample pretreatment, addressing NSB, concentration without evaporation, proper fragment choice One extraction method was developed for 4 insulin analogs from human plasma A single simple, analytical scale LC method was developed for separation of 4 synthetic insulin analogs Limit of detection for all 4 insulins was 50 pg/mL in solvent standards Detection or quantitation limits of 0.2 to 0.5 ng/mL were achieved for all 4 insulin analogs extracted from 250-300 µL human plasma Shows promise for direct quantification of intact insulins in plasma ©2012 Waters Corporation 37 Acknowledgements Waters Corporation Erin Chambers Martha Stapels Joanne Mather Damian Morrison Stephan Koza StJohn Skilton Scott Berger ©2012 Waters Corporation 38