Types of Evaporation & Pharmaceutical Processes PDF

Types of evaporation small scale evaporation Large scale methods ØEvaporating pans ØEvaporating stills üWhat they are? üadvantages and disadvantages of using each method Applications of evaporation 1. One of the most important method in manufacture of pharmaceuticals. 2. Used for preparation...

Types of evaporation small scale evaporation Large scale methods ØEvaporating pans ØEvaporating stills üWhat they are? üadvantages and disadvantages of using each method Applications of evaporation 1. One of the most important method in manufacture of pharmaceuticals. 2. Used for preparation of different type of extracts. 3. In the manufacture of drugs containing antibiotics, hormones, enzymes etc. 7. Dessication Introduction Desiccation is the process of removing adhered moisture from liquid or solid substances Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic substance ,that induces or sustains such a state (Dryness) in its local vicinity ,in a moderately sealed container. A desiccator is a heavy glass or plastic container used for making or keeping small amounts of material very dry. The material is placed on a shelf, and a drying agent or desiccant, such as dry silica gel or anhydrous sodium hydroxide, is placed below the shelf. Application In preservation of vegetable and animal drugs that are destroyed in presence of moisture. Comminution of drugs is difficult when they are wet, but it becomes easy when they are dried. To decrease the bulk and weight of substances containing moisture to facilitate their easy handling. To increase the stability of drugs 8. Levigation  Levigation is commonly used in small scale preparation of ointments to reduce the particle size and grittiness of the added powders. A mortar and pestle or an ointment tile is used for this purpose. A paste is formed by combining the powder and a small amount of liquid (the levigating agent) in which the powder is insoluble The paste is then triturated in the mortar by the pestle or on the ointment tile by a spatula to reduce the particle size.  The levigated paste is then added to the ointment base and the mixture is made uniform and smooth by rubbing it together with a spatula on the ointment tile The most common levigating agents are mineral oil, water, alcohol and glycerin. The process of levigation is also known as wet grinding and is used to reduce the particle size of a substance to finer state of subdivision This process is often used to incorporate solid substances into dermatological and ophthalmic ointments and suspensions. Application 1. Size reduction 2. Preparation of ointment