Fatty-lipophilic bases ( Oleaginous ) for rectal suppositories
1) Cocoa butter ( Natural ):
They are triglyceride fatty bases, i.e. a mixture of glycerin with fatty acids. They are used as fatty bases in rectal suppositories. They are naturally extracted from roasted Theobroma cacao seeds. They are characterized by several factors, including: they dissolve at body temperature, which helps in better drug release, non-reactive and bland , These bases can be distinguished by: They are yellowish-white and brittle fat that melts at a temperature between 30-35, and they must be kept in a cool, quilted place and protected from light . Cocoa butter is found in four crystalline forms, including:
- Beta crystal ( stable ): melt at 34-36 Celsius.
- Beta’ crystal ( unstable): melt at 27 Celsius.
- Gama y ( unstable): melt at 18 Celsius.
- Alpha ( unstable): melt at 22 Celsius.
2) Hydrogenated fatty acids ( synthetic): They are hydrogenated fatty acids extracted from vegetable oils such as palm oil and cottonseed oil. These compounds contain higher molecular weight fatty acids such as palmitic and stearic acids with glycerin , Advantages and disadvantages of synthetic lipophilic bases:
- Readily available
- Inert compounds, meaning they do not react.
- Don’t exhibit polymorphism
- Good water absorption
- Fast solidification
- Don’t become rancid
- lubrication can be avoided
- General appearance features: white, smooth and odorless
- It may become brittle and fracture if cooled quickly
- More expensive than cocoa butter ( natural)