Purpose

Define user requirements for a standalone FUZKK utility that accepts laboratory CSV data, evaluates the records using limits embedded in code, and produces LabWare-compatible JSON.

Scope

The utility is intended for preliminary QC/QA review, integration testing, LIMS/LabWare flow and evidence-trail preparation. Final release decisions remain under the laboratory's validated procedure and responsible personnel.

Users

QC analyst, QA reviewer, CSV/validation engineer, LIMS/LabWare integration engineer, responsible laboratory specialist.

User requirements

1. The utility shall run without arguments and print its self-description, a built-in input.csv example from GetDemoData(), and demo evaluation for the embedded records.
2. The utility shall run with two arguments: input.csv output.json.
3. The utility shall not read input.csv and shall not write output.json when started without arguments.
4. CSV numeric values shall be parsed using CultureInfo.InvariantCulture.
5. Output shall be generated as LabWare-compatible JSON with Header, Samples, Results, Status, StatusCode, ErrorMessage, Description and DescriptionEN.
6. For PASS records, ErrorMessage shall be an empty string.
7. Embedded limits shall follow this priority: Ph. Eur. → British Pharmacopoeia / UK implementation → EAEU / regional requirements → EMA/ICH/EU guidance → USP fallback.
8. If an exact monograph is not known, strict standard API limits are used where applicable: assay 98–102%, total impurities ≤1.0%, individual impurity ≤0.5%.
9. For biologics and mAb-like products, aggregation, sterility and endotoxin checks shall be included where relevant to the utility purpose.
10. If a parameter may arrive in different units, the unit shall be represented as a separate input field or explicitly reflected in the input.csv field name.

Input CSV

BatchNumber,ProductName,TotalImpurities_Percent,SingleLargestImpurity_Percent,DeletionSequences_Percent,InsertionSequences_Percent,OxidationForms_Percent,DeamidationForms_Percent,ResidualSolvents_PPM,Reagents_PPM,Purity_MainPeak_Percent
PEP-IMP-2026-001,Semaglutide API,1.2,0.3,0.2,0.05,0.15,0.1,120.0,50.0,98.8
PEP-IMP-2026-002,Liraglutide Bulk,1.5,0.4,0.3,0.1,0.2,0.15,150.0,60.0,98.5
PEP-IMP-2026-003,Tirzepatide API,0.8,0.2,0.1,0.02,0.1,0.05,80.0,30.0,99.2

input.csv fields

Utility description

Peptide Impurity Profile Analyzer — Peptide Impurity Profile Analyzer

Peptide Impurity Profile Analyzer — Peptide Impurity Profile Analyzer

ℹ️ Utility analyzes complex peptide impurity profile:
• Main peak purity (≥98.0%)
• Total impurities (≤2.0%)
• Deletion/insertion sequences
• Oxidized and deamidated forms
• Residual solvents and reagents

⚠️ CRITICAL: Deletion sequences may have different biological activity!
Deamidation changes charge and pharmacokinetics.

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

Input format:
BatchNumber,ProductName,TotalImpurities_Percent,SingleLargestImpurity_Percent,DeletionSequences_Percent,InsertionSequences_Percent,OxidationForms_Percent,DeamidationForms_Percent,ResidualSolvents_PPM,Reagents_PPM,Purity_MainPeak_Percent

Example:
PEP-IMP-2026-001,Semaglutide API,1.2,0.3,0.2,0.05,0.15,0.1,120.0,50.0,98.8

— WHY IS THIS NEEDED?
Impurity control is critical for peptide drugs (Novo Nordisk, Eli Lilly, Gan & Lee):
• Peptide synthesis (SPPS) generates specific impurities: truncated chains, insertions, racemates
• Post-translational modifications (oxidation, deamidation) occur during storage
• Impurities may have immunogenic potential or alter pharmacokinetics
• Regulators require identification and control of all impurities >0.1%

⚠️ CRITICAL:
• Main peak purity ≥98.0% — standard for highly purified peptides
• Total impurities ≤2.0% — strict safety limit
• Deletion sequences ≤0.5% — synthesis efficiency control
• Oxidized forms ≤0.5% — stability control (Met, Trp)
• Deamidated forms ≤0.5% — stability control (Asn, Gln)
• Residual solvents ≤500 ppm — ICH Q3C compliance

Key features:
• Detailed impurity profile breakdown by type (synthetic vs degradation)
• Control of specific peptide impurities (deletion/insertion)
• Purification quality assessment (HPLC prep)
• Support for various peptides (Semaglutide, Liraglutide, Tirzepatide)

Critical parameters:
• Main peak purity: ≥98.0%
• Total impurities: ≤2.0%
• Largest impurity: ≤0.5%
• Deletion sequences: ≤0.5%
• Oxidized forms: ≤0.5%
• Deamidated forms: ≤0.5%

💡 Usage tips:
1. Use MS detector for accurate mass identification of impurities
2. Separate synthetic impurities (process) from degradation (storage)
3. For deamidation, use peptide mapping
4. Control TFA (trifluoroacetic acid) level as key reagent
5. Compare profiles of different batches to monitor synthesis process stability

⚠️ Note: Unlike small molecules, peptides have many structurally similar impurities (e.g., differing by one amino acid). Their separation requires high-performance chromatography (UPLC) and sensitive detection.

Traceability and limitations

• The URS is used as the source document for functional specification, CSV review and later validation work.
• This document does not replace an approved pharmacopoeial monograph, validated analytical method or internal product specification.
• For product-specific limits, the approved customer specification takes priority.

The functional specification describes the behaviour of the standalone FUZKK console utility, input-data format, evaluation algorithm and output JSON structure.

Functional flow

1. Main() checks the number of arguments.
2. If no arguments are provided: PrintHello() prints the description and built-in input.csv example, then RunDemoEvaluation() executes Evaluate() over GetDemoData() and prints demo JSON.
3. If two arguments are provided: RunWithFiles(input.csv, output.json) reads CSV, evaluates each record and writes LabWare-compatible JSON.
4. LoadData() uses CultureInfo.InvariantCulture and shall not be called in no-arguments mode.
5. Evaluate() returns a named tuple with BatchNumber, ProductName, Parameters, CriticalFailCount, WarningCount, Recommendation and RecommendationEN.
6. GetIssues() builds messages for ErrorMessage in WARNING/FAIL cases.

Evaluation rules

• PASS: CriticalFailCount = 0 and WarningCount = 0.
• WARNING: CriticalFailCount = 0 and WarningCount > 0.
• FAIL: CriticalFailCount > 0.
• ERROR: exception during reading or processing.
• ErrorMessage remains empty for PASS.
• Limits are embedded in Program.cs; no external limit configuration is required.

Input and fields

BatchNumber,ProductName,TotalImpurities_Percent,SingleLargestImpurity_Percent,DeletionSequences_Percent,InsertionSequences_Percent,OxidationForms_Percent,DeamidationForms_Percent,ResidualSolvents_PPM,Reagents_PPM,Purity_MainPeak_Percent
PEP-IMP-2026-001,Semaglutide API,1.2,0.3,0.2,0.05,0.15,0.1,120.0,50.0,98.8
PEP-IMP-2026-002,Liraglutide Bulk,1.5,0.4,0.3,0.1,0.2,0.15,150.0,60.0,98.5
PEP-IMP-2026-003,Tirzepatide API,0.8,0.2,0.1,0.02,0.1,0.05,80.0,30.0,99.2

Output JSON

{
  "Header": {
    "UtilityName": "Peptide_ImpurityProfile_Analyzer",
    "Version": "1.0.0",
    "Timestamp": "UTC",
    "InstrumentID": "FUZKK-QC-WORKSTATION",
    "OperatorID": "Admin"
  },
  "Samples": [
    {
      "SampleID": "from BatchNumber",
      "BatchNumber": "from CSV",
      "ProductName": "from CSV",
      "TestName": "utility-specific test",
      "AnalysisCode": "utility-specific code",
      "Status": "PASS | WARNING | FAIL | ERROR",
      "StatusCode": "1 | 2 | 0 | -1",
      "ErrorMessage": "",
      "Description": "Russian recommendation",
      "DescriptionEN": "English recommendation",
      "Results": [
        {
          "ParameterName": "parameter",
          "ResultValue": 0.0,
          "UnitOfMeasure": "unit",
          "SpecificationLimit": "limit",
          "IsWithinSpec": true
        }
      ]
    }
  ]
}