Impurities in pharmaceutical products do not offer any therapeutic benefit for the patient and sometimes they are potentially toxic. The impurity level is a critical quality attribute for a drug substance or a drug product. Impurity control is one of the most important tasks in a process scale-up.
Pharmaceutical impurities can be controlled by understanding the formation, fate, and purge of the impurities during the manufacturing process. They can be controlled by setting up appropriate controls at places where they either enter or form during the manufacturing process of drug products.
Impurities can have many unwanted effects, such as:
1. Decreasing the therapeutic effect:
Minimizing side effects requires recognition and quantification of the treatment in multiple dimensions. In the specific case of targeted pharmaceutical interventions, a combination of therapies is often needed to achieve the desired results.
2. Lowering product shelf-life:
Pharmaceutical products are assigned a shelf-life which determines the time when a product is considered to be safe and effective under a relevant storage condition. A number of factors are used to assign that shelf-life. Among these factors is Lowering product shelf-life and the chemical stability of the active pharmaceutical ingredient (API) in its dosage form.
3. Inducing toxicity:
Drug toxicity refers to the level of damage that a compound can cause to an organism. Drug toxicity usually occurs at doses that exceed the therapeutic efficacy of a drug; however, toxic and therapeutic effects can occur simultaneously. It can be assessed at the behavioral or physiological level.
Some basic strategies for controlling pharmaceutical impurities are:
- Control of input material attributes (e.g., starting materials, API, reagents, intermediates, excipients, primary packaging materials) based on an understanding of their impact on processability or product quality.
- Control of in-process materials.
- Product specifications.
- Controls for unit operations that have an impact on downstream processing or product quality (e.g., the impact of drying on degradation).
- In-process or real-time release testing in lieu of end-product testing (e.g. measurement and control of CQAs during processing).
- A monitoring program (e.g., full product testing at regular intervals) for verifying multivariate prediction models.
Various advanced approaches for controlling Pharmaceutical impurities are mentioned below:
1. Material controls:
Based on the knowledge gained from a synthetic route, impurities can be controlled by testing them according to to set specifications. This enables us to eliminate the impurities before beginning the process.
2. Process controls:
These are the controls that are put into place in order to monitor and adjust the process by ensuring that an API or its intermediates conform to its specifications.
3. End product testing:
Impurities that are formed during the late stages of product development can be controlled by end-product testing with appropriate specifications.