Loss on Drying (LOD) is a gravimetric analytical method used to determine moisture content and volatile substances in pharmaceutical substances, excipients, finished dosage forms, food materials, and chemical products. The loss on drying method measures the weight reduction of a sample after drying under specified temperature conditions, typically 105°C unless otherwise defined in a monograph. The standard LOD test procedure involves: • Accurately weighing the sample • Drying at a prescribed temperature • Cooling under controlled conditions • Reweighing until constant mass • Calculating percentage weight loss Because water and volatile matter directly affect product stability, potency, and shelf life, the loss on drying test remains a mandatory quality control parameter in regulated industries. The loss on drying test is formally defined in major international pharmacopoeias: • United States Pharmacopeia (USP <731> Loss on Drying) • British Pharmacopoeia (Appendix IX D) • Japanese Pharmacopoeia • Chinese Pharmacopoeia (General Chapter 0831) Although wording varies slightly, pharmacopoeial loss on drying requirements generally include: • Drying to constant mass • Specified temperature (commonly 105°C)

• Use of appropriate weighing precision • Controlled environmental conditions Compliance with pharmacopoeia loss on drying chapters is essential for pharmaceutical manufacturers and contract testing laboratories. Many users searching for “loss on drying” are comparing it with other moisture determination methods such as Karl Fischer titration. • Loss on Drying (LOD) measures total weight loss, including water and volatile substances. • Karl Fischer specifically measures water content only. For materials where volatile solvents or residual organics may be present, the LOD method provides broader...

Labthink Instruments Co., Ltd. [email protected] +86-531-5870 2937 www.labthink.com Challenges of the Traditional Loss on Drying Method In many QC laboratories, the loss on drying test is still performed using a drying oven and an analytical balance. While compliant with pharmacopoeial requirements, this manual LOD workflow may introduce variability: Temperature Impact on Weighing Removing samples from a 105°C oven and placing them on an analytical balance may affect stability due to temperature gradients.

Operator-Dependent Variability Differences in cooling time, handling technique, and environmental exposure can influence repeatability. Increasing Regulatory Expectations Modern pharmaceutical laboratories must comply with: • GMP data integrity requirements Manual recording and decentralized systems may increase compliance risk. As regulatory oversight strengthens, laboratories are reviewing their LOD testing workflows. An automated loss on drying tester integrates drying, cooling, and weighing into a standardized system while maintaining the classical gravimetric principle defined by pharmacopoeias....

When selecting a loss on drying tester for pharmaceutical or chemical laboratories, consider: • 0.01 mg resolution for high-precision applications • Verified repeatability performance • Separation of drying and weighing • Stable temperature control up to 130°C • Automated sample movement • Multi-station capability • Reduced operator intervention • Audit trail • Electronic signature • Role-based user management • Network connectivity Choosing a compliant and automated loss on drying system can improve reproducibility, throughput, and inspection readiness. The loss on drying method is widely applied...

• Moisture analysis of raw materials • Regulatory food testing (e.g., GB 5009.3) Chemical Industry • Organic and inorganic materials • Industrial intermediates • Moisture and volatile content evaluation Because the LOD test is referenced in both pharmacopoeias and industrial standards, it remains a globally accepted method. Search trends show increasing interest in: • Automated loss on drying tester • Pharmacopoeia loss on drying equipment This reflects a shift from purely manual LOD execution toward standardized and automated solutions. While the scientific principle of loss on drying remains...