It is important for pharmaceutical and supplement manufacturers to understand cap. sizes. It influences the formulation design, the regulatory compliance, and the patient’s safety. This guide goes through capsule dimensions, capacity, and materials and helps you pick the right measurements for capsules for your manufacturing needs.
Understanding Capsule Sizes
Standard Capsule Sizes
Capsules are standardized globally and size 000 (the largest) to size 5 (the smallest, memory of a body to be penetrated). This universal sizing system is compatible regardless of whether you are using gelatin, HPMC, or pullulan and can be used with all capsule filling machines. If you do not know where you want to start, size 0 and 00 are often used in supplements as well as pharmaceuticals.
Size vs. Capacity
Size of capsule does not necessarily mean fill capacity. That instead of what fits depends on the density of your formulation. For instance, if powder has a lower bulk density, the same dosage you could fit in a smaller capsule with a denser powder, the capsule you need is bigger.
Capsule Size Specifications
Dimensions and Capacities
Volumes and physical dimensions of each capsule are different. Size 000 capsules are 26 mm long and can hold up to 1.37 mL while size 5 capsules are only 11 mm and only can contain 0.13 mL. This information also aids in selecting a capsule that fulfills your dosage and usability requirements.
Fill Weight Variations
Fill weight depends on the formulation’s bulk density. For example, a size 0 capsule could contain 408 mg (or less, up to 816 mg) of a substance having a density of 0.6 g/mL, depending on how dense the material is. During the formulation, be sure to adjust accordingly to ensure accuracy of dosage.
Empty Capsules Sizes Chart
| Size | Weight Capacity (mg, at 0.8 g/mL) | Volume Capacity (mL) | Empty Capsule Weight (mg) | Overall Closed Length (mm/in) | Individual Length (Cap+Body, mm) | External Diameter (mm) |
| 000 | 1100 | 1.37 | 158 | 26.14 / 1.03 in | Cap: 10.85 / Body: 18.00 | 9.91 |
| 00 | 720 | 0.90 | 123 | 23.3 / 0.92 in | Cap: 9.55 / Body: 17.6 | 8.53 |
| 0 | 540 | 0.68 | 99 | 21.7 / 0.85 in | Cap: 8.80 / Body: 16.6 | 7.65 |
| 1 | 400 | 0.48 | 78 | 19.4 / 0.76 in | Cap: 7.60 / Body: 14.9 | 6.91 |
| 2 | 300 | 0.36 | 61 | 18.0 / 0.71 in | Cap: 6.60 / Body: 13.2 | 6.35 |
| 3 | 240 | 0.27 | 48 | 15.9 / 0.63 in | Cap: 6.10 / Body: 11.6 | 5.82 |
| 4 | 180 | 0.20 | 38 | 14.3 / 0.56 in | Cap: 5.40 / Body: 10.2 | 5.31 |
| 5 | 120 | 0.13 | 28 | 11.1 / 0.44 in | Cap: 4.90 / Body: 8.5 | 4.91 |
Conclusion
Global standards on capsule size not only improve understanding of patient needs but also help to facilitate meeting regulatory expectations and attainment of formulation goals. When going through scaling up production or even creating a new formula, choosing the right sized capsule is critical towards safety and accuracy. Let size work for you, not against you.
FAQ’s
Which is the minimum size of capsules?
Size 5 is the smallest capsule if you are trying to keep fill weight down or improve the expected swallow comfort.
How do you calculate the size of capsules?
You figure it out from your fill materials’ density and dosage volume, and then find a size with enough capacity to match it.
