Dissolution and disintegration are both commonly used for checking the quality of solid oral dosage forms. While these two techniques are closely related, they give us different information about our products. Disintegration determines if our product breaks down into smaller fragments. Dissolution determines the rate that our drug dissolves in our media. While these are related to one another, they don’t always correlate to one another. Just because a product is quickly disintegrating doesn’t mean it also dissolves quickly!
Since disintegration only determines if a product breaks down into smaller fragments, we can’t use this as the only quality control check for most pharmaceuticals. Disintegration only may be an option when you have a product which is well-established and has a wide therapeutic index. Nutritional supplements such as vitamins and minerals generally fall into this category of disintegration only. If someone was taking vitamin C for example, this is something which would have a therapeutic effect and not lead to an overdose (wide therapeutic index) if the release was varied in a wide range. Some nutritional supplements though may require dissolution when the right dose is critical to health – such as folic acid for pregnant women.
Usually, we require dissolution to demonstrate proper release of a drug over time. These dissolution rates are correlated to in vivo data, and allows us to show that we have an adequate dose to deliver a therapeutic effect with minimal side effects. In modified release products, dissolution can determine if we can achieve a steady concentration of that drug as well in our bodies. Level concentrations of drug are essential in managing many conditions such as diabetes, high blood pressure, etc. where variability could lead to health complications.
Sometimes, we see dissolution apparatuses used for disintegration too. Oil-filled capsules may have disintegration testing done in dissolution units, called a rupture test. This is done using either a standard Apparatus 2 or 4 depending on the product’s requirements.
We also have many drugs which have dissolution requirements where disintegration isn’t needed. Suspensions and semisolids both wouldn’t be practical for disintegration, for example.
It’s important when starting work on a new product to determine whether disintegration, dissolution, or both are needed to ensure the safety and efficacy of your product. Whichever you need, Agilent is there to support your efforts.
Read also: Pharmaceutical Disintegrants and It’s Mechanism of Action
Resource Person: Ken Boda