Dissolution is an important part of capsule quality. In this stage, the capsule shell breaks apart after it enters the stomach or intestines. Once the shell dissolves, the medicine can be released into the blood. Therefore, the speed of capsule dissolution needs to be accurately controlled. It affects how quickly the medicine takes effect. If you want to produce capsules, the disintegration time must be considered.
Why is a proper dissolution time important?
This makes the medicine release at the right speed for the body to absorb it. If a pill dissolves too quickly, it might cause side effects. If it dissolves too slowly, the medicine may not work in time or may not provide the full effect. By controlling dissolution time, manufacturers can design capsules that act fast for quick relief or release slowly for long-lasting results.
How long does it take pills to dissolve?
The dissolution time depends mainly on product type and the coating used. Here are the common types and their usual dissolution times for your reference.
Gel capsules
As the most common dosage form, gelatin capsules are usually made in immediate-release types. They are made from animal-based gelatin, which softens quickly in the stomach. In most cases, a gelatin capsule will dissolve within 15 to 30 minutes after swallowing.
HPMC capsules
Vegetarian capsules are made from plant-based materials. Their shells are slightly more resistant compared to gelatin, so they usually take a little longer to break down. Generally, they dissolve within 20 to 40 minutes in the stomach.
Sofegels
Softgel capsules have a thin shell filled with liquid or oil. Because the shell is softer and the ingredients are in liquid form, softgels usually dissolve faster than hard capsules. They often break down within 10 to 20 minutes.
Capsules with enteric coating
These pills protect the medicine from stomach acid. Instead of dissolving in the stomach, they won’t break up until they reach the small intestine. This process takes longer, so they may take one to two hours to fully dissolve.
Controlled-release capsules
This type is designed to release contents slowly and steadily over time. The pills are made with special coatings to meet different dissolution times. This process can last for several hours, and in some cases up to 24 hours. It aims to make the drug level consistent and provide long-lasting effects.
How does the body absorb medicine?
Though there are many types of pills, the disintegration and absorption process is similar. Once the capsule shell breaks down, the active ingredients mix with the stomach acid. Then it enters the blood.
The blood then carries it and sends it to different organs and tissues. This process is called absorption. But absorption does not always mean the medicine kicks in. The drug still needs to reach the right spot in the body and act there.
For example, a painkiller may be absorbed into the blood within 20 to 30 minutes. But the patient usually feels relief closer to an hour later. The speed and amount of absorption depend on many factors, such as the pill type, the person’s metabolism, etc.
Three common factors affecting the dissolution of pills
Pill type
The capsule material plays a big role in how fast it dissolves. As we talked before, gelatin capsules usually dissolve faster than HPMC capsules, while softgels often break down even quickly. Some capsules designed with special coatings, like enteric-coated shells, dissolve more slowly.
Capsule size and thickness
Compared to smaller and thinner ones, larger capsules or those with thicker shells take longer to dissolve. The thickness of the capsule shell controls how quickly stomach acid can break it down. This is why some supplements in big capsules may feel like they take more time to start working.
Stomach acidity
The acid level in the stomach affects how easily a capsule shell breaks apart. A higher acid level usually helps capsules dissolve more quickly, especially gelatin types. If stomach acid is low, the process can be slower. This is one reason why people with digestive problems find out how fast their medicine works.
Why do you need capsule dissolution testing for production
The dissolution testing is a must. It measures how fast the drug is released and dissolved. Moreover, the test checks whether each batch of medicine dissolves consistently. It makes sure that a medicine dissolves in the right way so it can be absorbed and take effect. The dissolution test also ensures that every batch of medicine is consistent in quality. This is important for patient safety. In drug development, dissolution testing gives useful information to improve the formula. It is also a legal requirement in many pharmacopeias, such as the USP. In this way, the product can smoothly reach the market.
To keep results fair and reliable, the test must follow standard methods. In the U.S., the USP (United States Pharmacopeia) sets these rules. They describe four main types of machines for testing: basket, paddle, reciprocating cylinder, and flow-through cell. These machines can simulate how a drug dissolves inside the body. It allows manufacturers to see whether the medicine will release properly under different conditions. If the results do not meet the standard, the batch cannot be sold.
The end
Pill dissolution is key to the safety and effectiveness of medicines. It ensures that every capsule works as expected. Pill makers need to lay emphasis on this aspect for smooth and effective production.