CrosslinkingDegreeCalculator

Crosslinking Degree Calculator

dermal fillers endotoxins hyaluronic acid particles rheology sterility

Crosslinking Degree Calculator — Hyaluronic Acid Crosslinking Degree (ISO 13485, Ph. Eur.)

ℹ️ The utility calculates crosslinking degree via NMR/chemistry data, checks residual BDDE, correlation with rheology (G') and degradation resistance.
ℹ️ Does not use machine learning — rule-based logic and calculation formulas only.
⚠️ CRITICAL! Free BDDE is toxic (≤2 ppm). Crosslinking degree determines filler longevity and granuloma risk!

Usage:
CrosslinkingDegreeCalculator.exe → demo mode
CrosslinkingDegreeCalculator.exe input.csv output.json → evaluate data

Input format:
BatchNumber,NMR_Peak_Ratio,Free_BDDE_ppm,Total_BDDE_Added_mg,Bound_BDDE_Calculated_mg,HA_Weight_mg,Moisture_Percent,Gel_Modulus_G_prime_Pa,Viscosity_Pa_s,Swelling_Ratio,Degradation_Time_Hours,pH_Value,SterilityTest,Endotoxin_EU_ml

Example:
HA-XL-2026-001,0.12,1.2,25.0,23.8,1000.0,0.5,450.0,25.0,12.0,180.0,7.1,0,0.1

— WHY IS THIS NEEDED?
Hyaluronic Acid (HA) crosslinking degree — key quality parameter for dermal fillers:
• Determines gel resistance to biodegradation (duration of effect)
• Affects viscosity, elasticity (G') and lifting capacity
• Controls amount of free crosslinking agent (BDDE), which is toxic
• Low crosslinking → fast degradation, short effect. High crosslinking → granuloma risk, hardness
⚠️ CRITICAL:
• Crosslinking Degree 0.5–4.0% — optimal range for most fillers
• Free BDDE ≤ 2 ppm — strict toxicological limit (residual crosslinker)
• NMR Peak Ratio 0.05–0.25 — confirms correct crosslinking structure
• Elastic Modulus (G') must correlate with crosslinking degree (higher crosslinking → higher G')
• Swelling Ratio inversely proportional to crosslinking (higher crosslinking → lower swelling)
• Degradation Time ≥ 100 hours (in vitro) — minimum resistance to hyaluronidase
• Sterility and endotoxins — mandatory for injectable forms
⚠️ Note: Crosslinking degree calculated indirectly via ratio of bound BDDE to HA weight or directly via NMR peak integrals. Important to check correlation: if calculated crosslinking is high but G' is low — possible synthesis process violation. Free BDDE removed by dialysis or washing, its control critical for patient safety.

input.csv

BatchNumber,NMR_Peak_Ratio,Free_BDDE_ppm,Total_BDDE_Added_mg,Bound_BDDE_Calculated_mg,HA_Weight_mg,Moisture_Percent,Gel_Modulus_G_prime_Pa,Viscosity_Pa_s,Swelling_Ratio,Degradation_Time_Hours,pH_Value,SterilityTest,Endotoxin_EU_ml
HA-XL-2026-001,0.12,1.2,25.0,23.8,1000.0,0.5,450.0,25.0,12.0,180.0,7.1,0,0.1

URS & FS — user requirements and functional specification

This document defines user requirements and functional specification for the quality-control utility. It supports deployment discussion, IQ/OQ preparation and QC workflow integration.

Utility: CrosslinkingDegreeCalculatorAPI / object: Crosslinking Degree CalculatorCategory: Dermal fillers

1. Scope

The Crosslinking Degree Calculator utility is used for Crosslinking Degree Calculator. The actual input.csv is the source of truth for the input structure; control criteria are defined by the executable and the domain description.

The utility does not use machine learning; decisions are produced by deterministic rules.

Categories: Dermal fillers

Tags: dermal fillers, endotoxins, hyaluronic acid, particles, rheology, sterility

2. Execution modes

CrosslinkingDegreeCalculator.exe                            → demo mode
CrosslinkingDegreeCalculator.exe input.csv output.json      → evaluate data

3. Key controlled areas

purity and impurities
microbiology and pathogens
pH and physicochemical parameters

4. Domain limits and critical parameters

⚠️ CRITICAL! Free BDDE is toxic (≤2 ppm). Crosslinking degree determines filler longevity and granuloma risk!
⚠️ CRITICAL:
Crosslinking Degree 0.5–4.0% — optimal range for most fillers
Free BDDE ≤ 2 ppm — strict toxicological limit (residual crosslinker)
NMR Peak Ratio 0.05–0.25 — confirms correct crosslinking structure
Elastic Modulus (G') must correlate with crosslinking degree (higher crosslinking → higher G')
Swelling Ratio inversely proportional to crosslinking (higher crosslinking → lower swelling)
Degradation Time ≥ 100 hours (in vitro) — minimum resistance to hyaluronidase
Sterility and endotoxins — mandatory for injectable forms
⚠️ Note: Crosslinking degree calculated indirectly via ratio of bound BDDE to HA weight or directly via NMR peak integrals. Important to check correlation: if calculated crosslinking is high but G' is low — possible synthesis process violation. Free BDDE removed by dialysis or washing, its control critical for patient safety.

Limits stated in the description must be verified against the current approved specification, pharmacopoeial monograph and registration dossier before production use.

5. URS — user requirements

ID	Requirement	Criticality	Acceptance criterion
URS-001	The system shall accept an `input.csv` file for Crosslinking Degree Calculator with the exact columns listed in the “Input data contract” section.	High	A file with the correct header is processed without manual editing; missing mandatory columns produce FAIL/import error.
URS-002	The system shall support execution without arguments in demo mode and execution with `input.csv output.json` for user data.	Medium	Both execution scenarios produce a predictable result or clear diagnostic error.
URS-003	The system shall perform rule-based controls for: purity and impurities, microbiology and pathogens, pH and physicochemical parameters.	High	Each controlled parameter receives a status and message; the result does not depend on hidden Excel formulas or ML.
URS-004	The system shall preserve traceability between batch/lot, source values, applied rules and final verdict.	High	Output includes batch identifier, source values, parameter statuses and critical findings.
URS-005	The system shall generate machine-readable `output.json` for LIMS/ELN/MES, batch record and QA/QC review.	High	JSON contains overall status, check array, warnings, failures and source-file reference.
URS-006	The system shall support use in the client validation package: URS/FS, IQ/OQ preparation, installation and operational scenario checks.	High	The document, test scenarios and reproducible CSV/JSON flow are suitable for audit and internal approval.
URS-007	The system shall clearly separate technical data errors from specification nonconformities.	Medium	Schema/type errors are not mixed with pharmacopoeial deviations and are reported separately.

6. input.csv data contract

The source of truth for the input schema is the actual input.csv header. Column names are technical identifiers and are not translated.

#	Column	Type	Unit	Description	Sample	Control rule
1	`BatchNumber`	identifier	as specified	Batch Number	`HA-XL-2026-001`	mandatory field; used for batch/lot traceability
2	`NMR_Peak_Ratio`	decimal	as specified	NMR Peak Ratio	`0.12`	mandatory numeric value; rule comparison is performed by the utility
3	`Free_BDDE_ppm`	decimal	ppm	Free BDDE ppm	`1.2`	mandatory numeric value; rule comparison is performed by the utility
4	`Total_BDDE_Added_mg`	decimal	as specified	Total BDDE Added mg	`25.0`	mandatory numeric value; rule comparison is performed by the utility
5	`Bound_BDDE_Calculated_mg`	decimal	as specified	Bound BDDE Calculated mg	`23.8`	mandatory numeric value; rule comparison is performed by the utility
6	`HA_Weight_mg`	decimal	as specified	HA Weight mg	`1000.0`	mandatory numeric value; rule comparison is performed by the utility
7	`Moisture_Percent`	decimal	%	Moisture %	`0.5`	mandatory numeric value; rule comparison is performed by the utility
8	`Gel_Modulus_G_prime_Pa`	decimal	as specified	Gel Modulus G prime Pa	`450.0`	mandatory numeric value; rule comparison is performed by the utility
9	`Viscosity_Pa_s`	decimal	as specified	Viscosity Pa s	`25.0`	mandatory numeric value; rule comparison is performed by the utility
10	`Swelling_Ratio`	decimal	as specified	Swelling Ratio	`12.0`	mandatory numeric value; rule comparison is performed by the utility
11	`Degradation_Time_Hours`	decimal	h	Degradation Time Hours	`180.0`	numeric value; compared with individual or total impurity limit
12	`pH_Value`	decimal	pH	p H Value	`7.1`	mandatory numeric value; rule comparison is performed by the utility
13	`SterilityTest`	boolean / flag	0/1	Sterility Test	`0`	valid flag required; prohibited organisms and growth are normally expected as 0 / absent
14	`Endotoxin_EU_ml`	decimal	as specified	Endotoxin EU ml	`0.1`	numeric value; critical safety attribute compared with endotoxin limit

CSV example

BatchNumber,NMR_Peak_Ratio,Free_BDDE_ppm,Total_BDDE_Added_mg,Bound_BDDE_Calculated_mg,HA_Weight_mg,Moisture_Percent,Gel_Modulus_G_prime_Pa,Viscosity_Pa_s,Swelling_Ratio,Degradation_Time_Hours,pH_Value,SterilityTest,Endotoxin_EU_ml
HA-XL-2026-001,0.12,1.2,25.0,23.8,1000.0,0.5,450.0,25.0,12.0,180.0,7.1,0,0.1

7. FS — functional specification

ID	Function	Implementation description
FS-001	CLI entry point	The executable `CrosslinkingDegreeCalculator.exe` supports demo mode and `input.csv output.json` processing mode.
FS-002	CSV parser	The import module reads CSV, validates header, column presence/order, value count and encoding. Decimal values are expected with a dot separator.
FS-003	Field conversion	Each column is converted to the expected type: identifier, text, decimal number, date/time or boolean flag.
FS-004	Domain rule engine	For Crosslinking Degree Calculator, explicit rules are applied: range, minimum, maximum, absence of prohibited flag, data completeness or calculation-based check.
FS-005	Criticality handling	Critical violations produce FAIL; non-critical deviations and incomplete data produce WARNING; full conformance produces PASS.
FS-006	JSON writer	`output.json` stores overall status, per-parameter results, source values, warnings, failures and diagnostic messages.
FS-007	Integration contract	The CSV → JSON format is stable for invocation from LIMS/ELN/MES, scheduled task or wrapper service.
FS-008	Error handling	Schema error, missing file, non-numeric value or JSON write failure returns diagnosable error without silent PASS.

8. output.json contract

The output file must be suitable for automated processing, audit review and correlation with the source input.csv row.

{
  "utility": "CrosslinkingDegreeCalculator",
  "api": "Crosslinking Degree Calculator",
  "batchNumber": "HA-XL-2026-001",
  "overallStatus": "PASS|WARNING|FAIL",
  "checkedAtUtc": "2026-05-18T00:00:00Z",
  "checks": [
    {
      "parameter": "BatchNumber",
      "value": "HA-XL-2026-001",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "NMR_Peak_Ratio",
      "value": "0.12",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Free_BDDE_ppm",
      "value": "1.2",
      "unit": "ppm",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Total_BDDE_Added_mg",
      "value": "25.0",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Bound_BDDE_Calculated_mg",
      "value": "23.8",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "HA_Weight_mg",
      "value": "1000.0",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Moisture_Percent",
      "value": "0.5",
      "unit": "%",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Gel_Modulus_G_prime_Pa",
      "value": "450.0",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    }
  ],
  "criticalFindings": [],
  "sourceFile": "input.csv"
}

9. OQ/PQ test scenarios

ID	Scenario	Expected result
TC-001	Valid CSV with expected header and sample row	All rows are processed; output contains PASS/WARNING/FAIL and parameter-level detail.
TC-002	A mandatory input.csv column is missing	Import is rejected or the row receives FAIL with schema reference.
TC-003	A numeric field contains text or a blank value	Type conversion error is recorded; the result is not hidden as PASS.
TC-004	A parameter is outside specification or critical limit	Critical parameters produce FAIL; non-critical deviations produce WARNING according to the rule.
TC-005	Positive pathogen/microbiological flag or microbiological limit excursion	Critical FAIL is produced with the offending parameter.

10. QA/QC, CSV and change control

Before production use, the client records executable version, checksum, specification/monograph version, test CSV, expected JSON and IQ/OQ results.
Column names must not be changed without updating the validator and test scenarios.
The source CSV, output.json and utility version should be stored together as an evidence package.
Any change in control rules must go through change control and repeated OQ scenario verification.

Included in packages

Dermal Fillers QC Suite

Package for injectable implants and dermal fillers: hyaluronic acid, CaHA, PLLA, PMMA, collagen and related tests.

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