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Herbs were the main source of medicine during the earlier days. With the advancement of sciences, scientists could identify the components of herbs that are responsible for medicinal actions. The components are separated from the herb and used as such. A lot of them are modern allopathic medicines and they are synthesised commercially. When the active compounds are separated from the crude drugs, the process is called extraction and the products extracted are known as extracts. The statement, Galenicals are the crude extracts that are obtained from vegetable crude drugs or animals, is enough to answer the question, what are Galenicals in pharmaceutics?
What is galenical used for in pharmacy?
Galenicals are used to prepare medicines from crude drugs. Various methods of preparation are used according to the needs. Pharmaceutical preparations are divided into two types of preparations i.e. galenical preparations method and the non-galenical preparations method.
Galenical preparations method
Galenicals were discovered by Galen. Water, alcohol, and ether could be used for extraction. The therapeutically active components in plants are known as active principles. Other components of the plants are considered inert. Alkaloids, sugars, gums, starches, glycosides, mucilages, proteins, cellulose, and oils are some important plant components. The purpose of extraction is to leach out the desired components by using solvents.
Selecting solvents
The ideal solvent that would be used for extraction should contain the property of dissolving only the active components of the plant. Such types of solvents are not available. Therefore, the solvent that will be used is selected on the basis that it can dissolve the active components to the maximum and the unwanted components to the minimum. In some cases, a mixture of solvents is used which is called menstruum. Other than this, the solvents that will be used should be available easily, are safe, retain potency and are easy for subsequent processing. Water and alcohol mixture is one of the most commonly used solvents.
Methods of Extractions
There are many methods of extraction that are used to extract the active components of the plants. Maceration and Percolation are the two methods mainly used. Other methods are infusion, decoction, hot continuous extraction, etc.
- Maceration- The word maceration means ‘soaking’. The process involves soaking the powdered crude drug with the menstruum in a closed container. The container will be closed for a period that is enough for menstruum to enter into the cellular structure of the crude drug and dissolve all the soluble constituents. The powder should be placed with the menstruum in a closed vessel with a wide mouth.
- Percolation- In this process, the extraction of powdered drugs is done by passing the menstruum slowly through a column of drugs. Generally, a percolator is used for the process. This is the most frequently used process in the extraction of active ingredients to prepare tinctures and fluid extracts. Percolators are available in different sizes, shapes, and utilities. Glass percolators are usually cylindrical shaped and are used for small-scale extractions. The percolators used in industries are made of stainless steel or are metal vessels with a glass lining.
- Infusion- This is the simplest method of extraction. A certain weight of the crude drug is prepared and the calculated amount of hot menstruum is added to the drug and it will be soaked for a definite time. The container must be stirred during infusion and heat should be retained. Fresh infusion should be used within 12 hours. A lot of medicines that were prescribed needed infusion of components such as cloves, bitter orange, or senna.
- Decoction- In the process of decoction, a specified volume of water is taken and the crude drug is boiled for a specified time then it is cooled and filtered. This process of decoction is used for the extraction of water-soluble and heat-stable components. Generally, this process is used in the preparation of Ayurvedic extracts known as “kawath”. The beginning ratio of crude drug to water was fixed. Then, the volume is boiled and brought down to 1/4th of its original volume. After this, the concentrated extract may be used as it is or could be processed further.
Conclusion
The active components of plants are extracted to make medicines. A herb contains a lot of components in it but a certain active compound could be extracted for a specific use. Galenicals are the crude extracts that are obtained from vegetables, crude drugs or animals. The Galenical preparations method and non-galenical preparations method are the two methods of pharmaceutical preparations. Galenicals are used to make medicines. A solvent is used to dissolve the active plant components. Many methods are used to extract the active components of a herb. Maceration, percolation, infusion, and decoction are some popular methods used.
