Home > Technical Articles > Moisture Analysis
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Home > Technical Articles > Moisture Analysis
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Moisture analysis
is an important part of many pharmaceutical analytical requirements. Excess
water in a product can adversely impact a product’s stability and efficacy.
This is especially true with lyophilized materials. There are a variety of
ways to measure water.
Loss on DryingThe simplest is Loss on Drying, which involves heating a material at 105°C until a constant weight is achieved. This is a simple, direct, and effective method for many products. However, it cannot be used on thermally unstable products, or products which contain (or potentially contain) other volatile materials.
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Karl Fischer TitrationA more specific method is the Karl Fischer titration. This relies on the reaction of water with sulfur dioxide and iodine in the presence of base. It is a well known, well understood reaction. It is easily automated, with many automatic titrators available. However, it is not without potential problems. Many samples are hygroscopic, absorbing atmospheric moisture during handling. Also, the sample must be dissolved in a suitable solvent prior to titration, but the solvent itself must be as anhydrous as possible. Methanol or pyridine are frequently used. Finally, some compound types, especially aldehydes and ketones, will interfere with the Karl Fischer titration, necessitating the use of different reagents. |
| Since pharmaceutical sample sizes are frequently quite limited, all of these problems must be anticipated and overcome before the project is begun. WCAS has analyzed countless different sample types using these methods. We have experience in performing this analysis to validate lyophilization procedures. Give us a call and we can discuss what type of analysis will suit your particular needs. |
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