What are the characteristics and applications of HPMC hollow capsules?

In the 100-year history of capsules, gelatin has maintained its status as the mainstream capsule material due to its wide source, stable physical and chemical properties and excellent processing performance. As people's preference for capsules increases, hollow capsules are more widely used in the fields of food, medicine and health products. However, the occurrence and spread of mad cow disease and foot-and-mouth disease have caused people to worry about products of animal origin. The most commonly used raw materials for gelatin are the bones and skins of cattle and pigs, and their risks are gradually becoming a concern. In order to reduce the safety risk of hollow capsule raw materials, industry experts continue to research and develop suitable plant-derived capsule materials. In addition, with the increase in the variety of capsules, the diversity of its contents has gradually made people realize that there is a compatibility problem between gelatin hollow capsules and some contents with special properties. For example, content containing aldehyde groups or reacting to form aldehyde groups under certain conditions may lead to cross-linking of gelatin; strong reducing content may undergo Mailard reaction with gelatin (mailard reaction) ); The highly hygroscopic content will make the shell of the capsule lose water and lose its original toughness. Among them, hollow capsules made of hydroxypropyl methyl cellulose (hpmc) have formed large-scale production. Due to the difference in properties between gelatin and gelatin, the formulation of hpmc hollow capsules is more complicated, and some gelling agents need to be added, such as gum arabic, carrageenan (algae gum), starch, etc. The hpmc hollow capsule is a product with a natural concept. Its material and production process are approved by the Judaism, Islam and Vegetarian Association. It can meet the needs of people of various religions and dietary habits.

It has a higher acceptance and has a gelatin film. If the moisture content is below this limit, the gelatin film will be obviously brittle. Ordinary gelatin hollow capsules without any additives have a risk of more than 10% friability when the moisture content is 10%; when the moisture continues to decrease to 5%, 100% friability will occur. In comparison, the toughness of hpmc hollow capsules is much better, even if the ambient humidity is low, it still maintains good performance. Of course, the prevalence of brittleness of hpmc hollow capsules with different prescriptions under low humidity will be quite different. On the contrary, when the gelatin hollow capsule is placed in a high humidity environment, the capsule shell will become soft, deformed, or even collapse after absorbing water. hpmc hollow capsules can maintain good morphology and performance even under high humidity conditions. Therefore, hpmc hollow capsules are highly adaptable to the environment. This advantage is especially significant when the product sales area covers multiple climate zones or the storage conditions are relatively poor. Strong chemical stability The cross-linking reaction of gelatin capsules is a difficult problem encountered in capsule formulations. Because the aldehyde group of the content reacts with the amino group of the amino acid in gelatin to form a network structure, the capsule shell is difficult to dissolve under the dissolution conditions in vitro, thereby affecting the release of the drug. Hypromellose is a cellulose derivative that is chemically inert and has excellent compatibility with most substances, so hpmc hollow capsules have no risk of cross-linking reactions and have high chemical stability.