Dissolution testing is a process that helps determine a drug’s effectiveness as well as how much of the drug can enter systemic circulation before reaching its destination. This kind of testing, also known as drug release testing, is critical for ensuring quality control and the drug’s proper development, particularly with solid oral dosage forms. However, this procedure isn’t without its challenges, especially when the data from these tests is used in order to receive approval for commercialization.
Although dissolution testing is typically done via standardized processes, there are several obstacles that can arise along the way, potentially delaying those processes. Keep reading to find out more about dissolution testing, the challenges that can come up, and how to overcome them.
Dissolution Testing’s Role in Pharmaceutical Quality Assurance, Explained
As mentioned above, dissolution testing is a process meant to ensure quality control and assurance during the drug product’s development lifecycle. The bioavailability of the drug is determined in large part by how easily the drug’s API (active pharmaceutical ingredient) dissolves prior to absorption into systemic circulation. The dissolution testing process is meant to:
- quantify how quickly the drug dissolves from a physical dosage form (e.g. a tablet or capsule)
- recognize any sign of physical changes within the drug
- see how easily the drug dissolves in a person’s gastrointestinal tract prior to circulation
- assure performance consistency between different formulations and batches
- achieve excellent solubility so that the API can be released as intended
The dissolution rate of the drug’s active ingredient largely determines its bioavailability
This procedure plays a big part in assuring pharmaceutical quality control standards are being met. In fact, an in-vitro dissolution test takes place earlier on in the development cycle before conducting the in-vivo test. While many dissolution testing processes use either the basket or paddle USP apparatus, various other testing models are available to use depending on which type of drug is the subject of these tests.
A paddle and basket USP apparatus are commonly used for dissolution testing
The post-approval phase is another area where dissolution testing data plays a big role as far as maintaining performance standards after hitting the market. A major reason for this is because any changes to the drug will need to use this data to ensure the product will continue to work as intended, despite any changes made to its formulation after being approved for sale. This data will also be necessary in order to easily distinguish which batches are correct, and which ones are not.
Challenges in Dissolution Testing, and How They Can Be Addressed
Considering its importance in a drug’s developmental process, dissolution testing also has its fair share of hurdles to overcome. Pharmaceutical quality assurance students learning about good manufacturing practices in their program should particularly be aware of the drug’s variability. More specifically, variability in dissolution testing can be affected by the behaviour of the analyst doing the test, including their approach to filtering, sampling, and timing.
Differences with the equipment used—such as how different types of equipment are maintained, or if there are vibrations within the systems—can also play a role. Furthermore, people tend to have differing reactions to drugs, which can lead to inconsistencies in factors such as:
- Timing of the drug’s release
- How long the drug stays in the individual’s gastrointestinal tract
- The drug’s acidity level
There are also possible issues in using the same facility to perform both dissolution tests and method validation as it’s being approved to go to market. This can become even more apparent when the drug needs further analytical method transfers (e.g. performing tests in a different laboratory, or introducing a new facility for manufacturing) after receiving approval.
More Tips On Proper Dissolution Testing, and How to Avoid Mistakes
Testing the drug product for reproducibility between different facilities may not paint a full picture of the behaviour or variability of the dissolution method by the time the drug is approved. With this in mind, anyone involved in the testing should resist the temptation to evaluate the drug and finish the tests as quickly as possible. Rushing this process can result in developmental errors that necessitate extra testing.
With all of this in mind, it is important for those involved in dissolution testing to fully understand which factors can impact variability during the earlier stages of the tests, and address these factors with vigilance. If achieving optimal solubility is an issue, further dissolution testing may be needed in order to get the correct amount, as well as increasing the amount of amorphous solids and/or salt.
Introducing automation to dissolution tests can also reduce the risk of variability between different analysts. Additionally, proper maintenance of equipment used for testing must be a top priority, as well as ensuring that it will provide the best possible performance and operate normally and reliably.
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