Moisture_Sorption_Isotherm_Processor

URS & FS — User Requirements and Functional Specification

This document describes the controlled interface, user requirements and functional behaviour of Moisture_Sorption_Isotherm_Processor. The utility is intended for automated verification of laboratory, pharmacopoeial, analytical or manufacturing QC parameters using input.csv and producing a structured output.json result.

Domain limits and critical parameters

• • Equilibrium moisture at 75% RH: ≤5.0% (example)
• • Hysteresis index (adsorption/desorption difference): ≤1.0%
• • Water Activity (Aw): ≤0.60
• • Model fit quality (R²): ≥0.99
• • Allows prediction of product behavior under various storage conditions (ICH Q1A).
• • Hysteresis between adsorption and desorption curves indicates irreversible structural changes (e.g., amorphous-to-crystalline transition or polymer swelling).
• • Water Activity (Aw) is directly related to chemical stability and microbial growth risk (USP <1112>).
• • Data is used for packaging selection (barrier properties) and drying conditions.
• • Equilibrium must be reached at each humidity step (dm/dt < 0.002%/min).
• • Hysteresis should be minimal for stable crystalline substances.
• • Aw < 0.60 is a generally accepted threshold for preventing growth of most bacteria and molds.
• • GAB (Guggenheim–Anderson–de Boer) model is often used for fitting food and pharma product isotherms.
• • Hygroscopicity assessment at key points (75% RH).
• • Structural integrity control via hysteresis.
• • Water activity calculation for microbial risk assessment.
• • Moisture at 75% RH: <= 5.0%

URS — User Requirements Specification

input.csv contract

BatchNumber,Moisture75RH,Moisture90RH,Hysteresis,Aw,ModelR2
ISO-EXC-2026-001,3.5,6.2,0.4,0.45,0.998
ISO-API-2026-002,2.1,3.5,0.2,0.35,0.999
ISO-FAIL-HYST-003,8.5,15.0,3.5,0.75,0.985

FS — Functional Specification

Example output.json

{
  "utilityId": "moisture-sorption-isotherm-processor",
  "utilityName": "Moisture_Sorption_Isotherm_Processor",
  "overallStatus": "PASS|WARNING|FAIL",
  "sourceFile": "input.csv",
  "checks": [
    {
      "parameter": "BatchNumber",
      "value": "ISO-EXC-2026-001",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Moisture75RH",
      "value": "3.5",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Moisture90RH",
      "value": "6.2",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Hysteresis",
      "value": "0.4",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Aw",
      "value": "0.45",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "ModelR2",
      "value": "0.998",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    }
  ],
  "criticalFindings": [],
  "warnings": [],
  "generatedFor": "QA/QC review and LIMS integration"
}

Traceability matrix

OQ/PQ test scenarios

QA/QC and change control

• Do not rename columns without updating the validator, documentation and test set.
• Retain input.csv, output.json, executable version, documentation and checksum.
• Before production use, perform IQ/OQ/PQ or equivalent CSV/CSA verification.
• Critical limits must be verified against the approved specification, local SOPs and registration dossier.