Why Are There Medication Capsules?

Capsules are just a coat or vest of medicine, and their purpose is not just to make the medicine look good, but mainly to make it easy to take and achieve the best therapeutic effect.

The drugs taken by people when they are sick need to be digested and absorbed into the bloodstream through the gastrointestinal tract, and also broken down by the liver.

But a considerable number of powders, granules, liquids, and tablets of drugs either have a bitter and irritating taste, are easily volatile, or are easily broken down by saliva in the mouth. Some drugs may also be inhaled into the trachea, causing side effects.
Therefore, encapsulating drugs can not only protect the oral and digestive tract, but also make them easy to swallow and maximize their therapeutic effects.

To achieve the best effect of drugs, it is also necessary to avoid them being destroyed by human stomach acid, because some drugs need to be dissolved and absorbed in the intestine. Therefore, capsules made of special membrane materials (such as gelatin, cellulose, polysaccharides, etc.) are needed to fill various types of drugs such as powder and liquid into the capsules according to dosage.

In addition, drugs have a half-life, which refers to the time it takes for the drug's highest concentration in the blood to decrease by half.

The half-life of a drug reflects the rate of elimination (excretion, biotransformation, storage, etc.) of the drug in the body, indicating the relationship between the time the drug is in the body and the blood drug concentration. Therefore, it is the main basis for determining the dosage and frequency of medication administration.

Drugs with a long half-life are eliminated slowly in the body, resulting in longer intervals between administration; And drugs with short half lives are eliminated quickly in the body, resulting in shorter administration times.

For drugs with short half lives, frequent medication is required to maintain the drug concentration in the blood. To avoid the trouble of frequent medication, special capsules are needed to wrap the drug, which are called sustained-release capsules.

Extended release capsule drugs can also avoid the disadvantage of excessive fluctuations in drug concentration in the blood after frequent administration of general preparations, resulting in fluctuating effective blood drug concentrations. At the same time, the toxic side effects of sustained-release capsules are also smaller than those of general preparations.

So, many drugs, such as ibuprofen, aspirin, Tylenol, etc., have sustained-release capsule formulations.