Croscarmellose Sodium and Biodegradability: OECD 301D Results Explained

Summary

• Our Croscarmellose Sodium (batch CCS250707) was evaluated using the OECD 301D Closed Bottle test at 20 °C over 28 days. 

• Degradation profile: Day 7 = 36.33%, Day 14 = 64.75%, Day 21 = 92.07%, Day 28 = 95.08%. 

• These results indicate low persistence in typical aerobic wastewater conditions and support environmental stewardship goals.

• This is an environmental fate study, not a human safety or quality study. Patient safety is addressed by our routine QC and regulatory compliance.

What is OECD 301D and why it matters in Croscarmellose Sodium

OECD 301D is a respirometric test for biodegradability. The test places a small amount of the substance in mineral medium with a mixed microbial population in completely full, closed bottles, kept in the dark at constant temperature. Degradation is followed by dissolved oxygen analysis over 28 days. Oxygen uptake by microbes, corrected for a blank, is expressed as a percentage of the theoretical oxygen demand. 

In plain terms: the test measures how much oxygen microbes consume while breaking down the material. More oxygen consumption, corrected for the blank, means more biodegradation.

How our test was set up

• Inoculum: Activated sludge microbial seed

• Medium: Mineral medium with KH₂PO₄, CaCl₂, MgSO₄, FeCl₃

• Test concentration: Freshly prepared, 1 g/L

• Blank: Inoculated sample without test substance

• Reference substance: Sodium acetate, 10 mg/L

• Temperature: 20 °C

• Duration: 28 days

• Instrument: Oxygen electrode for dissolved oxygen measurements

  
  

These conditions follow the Closed Bottle procedure. Measurements are taken at day 0, 7, 14, 21, and 28. Biodegradation (%) is calculated from BOD versus theoretical COD.

Results for CCS250707

Time Point	Percent Biodegradation
Day 7	36.3
Day 14	64.75
Day 21	92.07
Day 28	95.08

What “95% at Day 28” means

Under standardized, aerobic conditions, most of the material is broken down by microorganisms within 28 days. This suggests low environmental persistence after use and disposal in typical wastewater treatment contexts. It supports EHS and sustainability objectives that many pharmaceutical companies track.

Human use vs environmental fate

OECD 301D is an environmental test. It does not evaluate toxicology or patient safety. It also does not alter excipient performance in your formulation. Quality and patient safety are handled through our routine QC, CoA, and regulatory compliance package. The biodegradability result simply describes what happens to the material in an aerobic aquatic environment after it leaves the product lifecycle.

A note on controls in the study

The test includes blank and reference series, and the procedure describes measurement of dissolved oxygen across all series to calculate percentage degradation. This setup confirms that microbial activity and the calculation method function as intended.

Limitations and next steps

The lab report includes usage restrictions. It states the report is provided for reference, is not approved by government authorities, and is not to be used for litigation, publicity, or as evidence. For public environmental claims beyond a summarized description, we plan to re-run OECD 301D at an accredited laboratory that permits public citation. 

What this means for formulators

• You can continue to evaluate CCS based on your standard performance criteria for disintegration and overall tablet quality.

• The biodegradation profile strengthens your downstream environmental stewardship narrative in sustainability reports.

• If you need a technical summary, batch CoA, or samples, contact our team. We will share the full test data on request along with any additional documentation you need for supplier qualification.

Environmental implications

• Low persistence in aerobic systems: A 95.08% result in OECD 301D at 28 days indicates rapid microbial breakdown in typical aerobic wastewater conditions. This lowers the chance of accumulation or long-range transport after use.

• Likely breakdown products: The respirometric method tracks oxygen uptake as microbes degrade the substance, which corresponds to conversion to carbon dioxide, water, and biomass under the test conditions.

• Not a bioaccumulation profile: Fast aerobic biodegradation suggests low potential to bioaccumulate in conventional wastewater pathways.

• Scope limits: OECD 301D represents freshwater, aerobic, dark, constant-temperature conditions. Results do not automatically extend to marine, sediment, or anaerobic environments.