Which material is good for edible capsule shells?

The material of the capsule shell directly affects the drug absorption effect and the applicable population. Currently, there are four types of mainstream materials on the market:

1, Analysis of Capsule Material Types

(1) Gelatin capsules

Made from animal skin and bone extracted collagen, with a neutral pH value and mainly composed of protein. The production process adopts low-temperature drying technology, resulting in high transparency and moderate elasticity of the finished product. The market share is about 65%, and most common drugs use this type of capsule. The advantage lies in low cost and mature technology, but the disadvantage is sensitivity to high temperature and humidity, and it is prone to softening and deformation when stored at temperatures exceeding 40 ℃, with low acceptance among Muslim and vegetarian communities.

(2) Hydroxypropyl methylcellulose (HPMC) capsules

It is processed by extracting cellulose from pine wood pulp and has obvious botanical characteristics. The production process adopts injection molding technology, and the capsule wall thickness is 0.02mm thinner than that of gelatin capsules. It is suitable for water containing materials such as traditional Chinese medicine powder and probiotics, and the dissolution time is 3-5 minutes slower than gelatin capsules. At present, it accounts for 40% of the health food market share, with the advantages of no animal ingredients and low allergenicity, but the disadvantage is that the raw material cost is 35% higher than gelatin.

(3) Pullulan polysaccharide capsules

The new material made from algae extract has amphiphilic structural characteristics. The moisture content of the finished product is only 5% -8%, and it remains stable in an environment with a relative humidity of 75%, making it particularly suitable for storing hygroscopic drugs. The dissolution rate varies with the pH value of the medium, and the gastric juice environment completely disintegrates in about 15 minutes. The raw material price is four times that of gelatin, and it is mostly used for high-end health products.

(4) Starch capsules

Made from modified corn or cassava starch, it has a short shelf life of only 18 months and should be stored away from light and moisture. The dissolution rate is the fastest, and it begins to disintegrate within 5 minutes after oral administration, making it suitable for rapid release formulations. The market share is less than 5%, the advantage is that it is completely biodegradable, the disadvantage is that it has low strength and is prone to breakage, and the filling efficiency is 20% lower than gelatin.

2, Material comparison dimension

(1) Dimension of raw material source: Gelatin has religious taboos and allergy risks, and vegetarians should choose HPMC or pullulan polysaccharide materials.

(2) Storage stability: Polysaccharides from pullulan have the best moisture resistance, starch capsules are most sensitive to humidity, and HPMC remains stable at 40% -60% humidity.

(3) Drug compatibility: It is recommended to use gelatin capsules for fat soluble ingredients, HPMC for water-soluble active ingredients, and preferred for probiotics and other live bacterial preparations is pullulan polysaccharides.

(4)Dissolution characteristics: Gelatin capsules are suitable for gastric soluble drugs, HPMC material is recommended for enteric coated preparations, and pullulan polysaccharide is recommended for sustained-release drugs.

3, Purchasing Practice Guide

(1) Check the implementation standards for product packaging labeling. Medical grade should comply with the hollow capsule standard of the Chinese Pharmacopoeia, and food grade should comply with the GB 678-201 standard.

(2) Observe the sealing degree of the capsule joint. The gap of high-quality products should not exceed 0.1mm, while inferior products often have obvious cracking.

(3) Conduct dissolution test: In 37 ℃ warm water, qualified products should completely disintegrate within 15 minutes. Failure to dissolve after 30 minutes may indicate quality issues.

(4) To detect heavy metal residues, the lead content in capsule shells from reputable manufacturers should be less than 0.5mg/kg, and the arsenic content should not exceed 1.0mg/kg.

4, Precautions

Patients with diabetes should be cautious in using capsule excipients containing maltodextrin, and patients with thyroid disease should check the iodine content of the capsule. Special drugs such as ibuprofen sustained-release capsules cannot be taken in a detachable shell, and enteric coated preparations may irritate the gastric mucosa after damage. When children choose capsules, it is recommended to choose capsule 0 (volume 0.13ml) for those under 3 years old, and capsule 2 (volume 0.37ml) for school-age children.

5, Frequently Asked Questions

The difference in capsule color is due to the addition of food coloring and is not related to quality. Surface fogging of some HPMC capsules is a normal phenomenon and does not affect their use. Imported capsules require verification of customs inspection and quarantine certificates to prevent illegal channel products. The capsule is slightly deformed but not broken and can still be used. If adhesion and clumping occur, it needs to be scrapped. Capsules with special storage requirements are recommended to be equipped with a drying tank, and the built-in silicone desiccant needs to be replaced monthly.