Capsules are a solid dosage form in which the drugs and/or excipients are enclosed in a soft or hard soluble shell. Generally, drugs in capsules are powders or granules that are irritating to the esophagus and gastric mucosa that are easily volatile, easily decomposed by saliva in the mouth, easily inhaled into the trachea or have bad taste. These medicines are packed into capsules, which not only protect the medicine from being destroyed, but also protect the digestive organs and respiratory tract. Removing the capsule shell may cause drug loss, drug waste and reduced efficacy. In addition, some drugs need to be dissolved and absorbed in the intestine, and the capsule can protect the drugs from being damaged by gastric acid.

Capsule shell is usually made of gelatin or other suitable polymeric materials. According to the composition of capsule shell, capsule can be divided into hard capsules or soft capsules. In addition, capsules come in standard sizes. These sizes range from 000 to 5, which have volumes from 1.36 to 0.13 mL. The size of the 000 capsule is the highest, and 5 capsule is the smallest.

Capsules Fig.1 Diversity of capsules colors (Hoag S W, 2017)

Capsules Fig.2 Standard capsule sizes. Source: Dennis Murachanian, Capsulgel

The team of CD Formulation is leading experts in all aspects of pharmaceutical formulation development and dosage form optimization, we can accord the characteristics of the API and the development goals of the customers to design the capsules. CD Formulation can provide you with one-stop services to meet your needs of capsules.

Advantage of Capsules

  • Masking unpleasant odour and taste of the drugs
  • Smooth when moist and can be easily swallowed
  • Economical
  • Easy to handle and carry
  • Release the drug when desired in gastro-intestinal tract
  • Attractive in appearance

Capsules Fig.3 Hard capsules

Capsules Fig.4 Soft capsules

Disadvantage of Capsules

  • The hygroscopic drugs cannot be filled in capsules.They absorb water present in the capsule shell and hence make it very brittle, which ultimately breaks into pieces.
  • The concentrated preparations which need previous dilution are unsuitable for capsules because it may lead to irritation in stomach if administered as such.

The Process of Developing Ointments Capsules

For capsules, the formulation requires the formation of a uniform plug of uniform weight. Relative simplicity of capsule preparation that can speed up the development process, especially for drugs with large dose and difficult to compress.


How to Contact Us?

If you have a requirement about capsules services, please contact us by phone or email, our colleagues will reply to you within three working days.


  1. Pharmaceutical Dosage Forms: Capsules[M]. CRC Press, 2017.
  2. Gullapalli R P. Soft Gelatin Capsules (softgels)[J]. Journal of Pharmaceutical Sciences, 2010, 99(10): 4107-4148.
  3. Hoag S W. Capsules Dosage Form: Formulation and Manufacturing Considerations[M]//Developing Solid Oral Dosage Forms. Academic Press, 2017: 723-747.
  4. Fung K Y, Ng K M. Product-Centered Processing: Pharmaceutical Tablets and Capsules[J]. AIChE Journal, 2003, 49(5): 1193-1215.
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