Moisture content and LOD, in this article we will discuss the key differences between them as most of us cannot differentiate them when someone asks. Even I didn’t know the difference between them initially until one of my seniors asked me about it.  If you want to know why moisture content is different from LOD, read the article and polish your brain.

Moisture content and Loss on drying are critical parameters in pharmaceutical production as well as quality control as these influence important aspects related to drug products like stability, quality, and shelf life.

Excess moisture may degrade the products early microbial growth occurs and moisture levels are to be optimized as they influence the flow properties of powder during compression, filling of capsules, etc.

The measurement of above parameters are also very important from regualtory point of view as limits are set for each parameter by Pharmacopeias (such as the USP, EP, and JP).

MOISTURE CONTENT – It mainly refers to the total water content in a substance.

• The following methods are used to access the moisture content
• Karl Fischer Titration
• Gravimetric Method
• Near-Infrared Spectroscopy (NIR)

LOSS ON DRYING – Loss on drying measures the amount of weight lost by a substance when it is dried, which includes moisture content as well as other volatile substances.

Loss on drying or LOD refers to measuring the weight lost by substance, when it’s dried at a temperature. Substances which are lost during drying include moisture content (water ) as well as any volatile solvents present in the dried material.

Methods for measuring LOD

• Oven Drying Method
• Vacuum Oven Method
• Infrared Drying

Formula for LOD

% LOD = Initial weight – Final weight ÷ initial weight × 100

Where initial weight refers to the weight of sample before drying and final weight refers to weight of sample after drying.

I hope you all have learnt about the differences between LOD and Moisture content and methods for measuring these critical parameters and also their significance in product quality.