Iodine124MABQualityChecker

Utility description: Iodine-124 MAb

Iodine-124 MAb Quality Checker — Iodine-124 Monoclonal Antibodies (ImmunoPET)

ℹ️  Utility checks critical parameters of Iodine-124 labeled monoclonal antibodies:
    • Radiochemical purity (≥90%)
    • Free Iodine-124 impurity (≤5%)
    • Immunoreactive fraction (≥70%) — CRITICAL!
    • Aggregates (≤10%) — SAFETY & BIODISTRIBUTION!
    • I-123 (≤2%) and I-125 (≤1%) impurities
    • Specific activity, pH, endotoxins, sterility

⚠️  CRITICAL: Direct iodination (Chloramine-T, Iodogen) oxidizes tyrosine in the CDR region, potentially COMPLETELY DESTROYING antigen binding ability!
    Immunoreactivity control (Lindmo assay) is MANDATORY for each batch.
    Aggregates (>10%) accumulate in liver/spleen and increase anaphylaxis risk.

Usage:
  Iodine124MABQualityChecker.exe                            → demo mode (console output)
  Iodine124MABQualityChecker.exe input.csv output.json      → evaluate your data

Input format:
BatchNumber,RadiochemicalPurityPercent,FreeIodine124Percent,RadionuclidicPurityI123Percent,RadionuclidicPurityI125Percent,SpecificActivityMBqPerMg,ImmunoreactiveFractionPercent,AggregatePercent,pH,EndotoxinsEU,SterilityTest,ProteinConcentrationMgPerMl

Example (sterility: 0=sterile, 1=contaminated):
  I124-MAB-2026-001,96.0,2.5,0.8,0.3,120.0,85.0,4.0,7.2,90.0,0,2.0

— WHY IS THIS NEEDED?
Iodine-124 MAb (ImmunoPET) — advanced molecular imaging technology:
• I-124 (T½=4.18 days, β+ 23%) is ideal for PET imaging of slow biological processes (antibody tumor accumulation takes 24–72 hours).
• Used for theranostics: same molecule for diagnostics (I-124) and therapy (I-131).
• Allows quantitative assessment of antibody delivery to tumor before therapeutic dose.

⚠️  CRITICAL:
• Immunoreactive fraction ≥70% — proves that iodination DID NOT DAMAGE the binding site. Determined by Lindmo assay with excess antigen.
• Radiochemical purity ≥90% — free I-124 accumulates in thyroid and stomach.
• Aggregates ≤10% — controlled by SEC-HPLC. Aggregates = immunogenicity + false RES uptake.
• I-123 impurity ≤2% — short-lived impurity, affects activity calibration.
• I-125 impurity ≤1% — long-lived impurity (T½=59.4d), waste disposal issue.
• Specific activity ≥50 MBq/mg — ensures sufficient PET signal without antigen saturation.

Key features:
• Unique immunoreactivity control — parameter specific only to labeled proteins.
• Aggregate control as safety and image quality parameter.
• Separate control of I-123 and I-125 radionuclidic impurities.
• Support for biologic product requirements (endotoxins ≤350 EU/vial).

Critical parameters:
• Radiochemical purity: ≥90.0%
• Free Iodine-124: ≤5.0%
• Immunoreactive fraction: ≥70.0% (CRITICAL!)
• Aggregates: ≤10.0%
• I-123 impurity: ≤2.0%
• I-125 impurity: ≤1.0%
• Specific activity: ≥50 MBq/mg
• pH: 6.0–8.0
• Endotoxins: ≤350 EU/vial
• Sterility: no microbial growth

💡 Usage tips:
1. Immunoreactivity determined by Lindmo assay: series of antigen dilutions at fixed labeled antibody concentration, extrapolation to infinite antigen excess.
2. Aggregates controlled by size exclusion chromatography (SEC-HPLC, TSKgel G3000SWxl column or equivalent).
3. To reduce antibody damage, use indirect labeling via Bolton-Hunter reagent or thiol conjugation.
4. I-124 has complex decay scheme (multiple gamma lines) — use calibrated dose calibrator with I-124 correction factor.
5. Thyroid blocking with potassium iodide MANDATORY 24h before administration.

⚠️ Note: I-124 is ONE OF THE MOST COMPLEX isotopes for PET. High positron energy (E_max=2.14 MeV) reduces spatial resolution. Presence of cascade gamma rays (602 keV) requires random coincidence correction. Product quality directly determines feasibility of quantitative SUV analysis.