When it comes to pharmaceuticals, impurity standards are essential in ensuring both the safety and efficacy of these products. Impurities can come from a variety of sources, including the manufacturing process, ingredients, and storage conditions. As such, it is important for pharmaceutical companies to put in place stringent standards to ensure that these impurities are kept to a minimum.
There are a number of international pharmacopoeias that provide guidance on acceptable levels of impurities in pharmaceuticals. In the United States, the USP sets the standards that all pharmaceutical companies must adhere to. The USP defines an impurity as “any substance not intended to be an active ingredient of the drug product, including those that may arise during the course of manufacture or storage.”
There are a number of different types of impurities that can be present in pharmaceuticals, including residual solvents, degradation products, and process-related impurities.
Residual solvents are solvents that may be left over from the manufacturing process and can pose a safety risk if not properly removed.
Degradation products are formed during the storage of pharmaceuticals and can impact the efficacy of the product.
Process-related impurities are generated during the manufacturing process and can also impact the safety and efficacy of the product.
It is important for pharmaceutical companies to establish robust impurity testing and control procedures to ensure that products meet the relevant standards. There are a number of analytical techniques that can be used for impurity testing, including chromatography, spectroscopy, and mass spectrometry. These techniques can be used to identify, quantify, and characterize impurities.
Chromatography
- Chromatography is a powerful analytical tool that can be used for the detection and quantification of impurities in a variety of sample types. In general, chromatography works by separating the components of a sample by their interaction with a stationary phase and a mobile phase.
- One of the main advantages of chromatography is its high sensitivity. This means that it can be used to detect even very low levels of impurities in a sample.
- In addition, chromatography can be used to quantitate impurities, which is important for quality control purposes.
Spectroscopy
- Infrared spectroscopy can be used to identify and quantify the presence of various impurities in a sample.
- Mid-infrared spectroscopy is the most commonly used type of spectroscopy for impurity testing. This method uses a mid-infrared laser to irradiate the sample, and the absorbance of the light by the sample is measured.
- One advantage of using spectroscopy for impurity testing is that it is a non-destructive technique. This means that the sample can be analysed multiple times, which is important for quality control purposes.
Mass spectrometry
- This technique can be used to analyse both organic and inorganic compounds.
- This technique is highly sensitive and can be used to detect impurities at levels below the detection limit of other methods.
- There are a variety of mass spectrometry techniques that can be used for impurity testing. These techniques include inductively coupled plasma mass spectrometry (ICP-MS), electrospray ionization mass spectrometry (ESI-MS), and gas chromatography mass spectrometry (GC-MS).
Pharmaceutical companies should also put in place procedures to prevent and mitigate the impact of impurities on product quality. This can include steps such as source control, process optimization, and product testing. By putting place these procedures, pharmaceutical companies can help ensure that their products meet the highest quality standards.
