GPAT 360

Identification of Emulsion type. Basically, emulsions are of two types : o/w and w/o . Click here to view the article on What is an Emulsion? Following tests are conducted in order to identify the type of emulsion. 1. Cobalt chloride test: Filter paper soaked in cobalt chloride solution and dried , changes colour from blue to pink when exposed to the o/w (oil in water) emulsion. 2. Dilution test: This test is based on the miscibility of continuous phase in the oil or water. For example, if water is added with stirring in o/w emulsion , it will easily disperse in added phase (water) but w/o emulsion will not get dispersed. This method causes phase inversion of emulsions upon dilution. 3. Conductivity test: An emulsion with water as a continuous phase (o/w emulsion) passes the electric current , whereas the w/o emulsion is not able to do so. 4. Direction of creaming: When densities of the water and oil phases are known, direction of creaming test identifies emulsion type.  Cre...

  LINCTUSES What is a Linctus? Linctuses are sweet, viscous liquid oral preparations containing medicinal substances which have demulscent, expectorant or sedative properties. These contain high proportions of syrup and glycerin which exert demulscent effect on the mucous membrane of throat. In order to obtain prolonged local action, linctuses should be administered slowly in undiluted form. Formulation of Linctus  1. Vehicle : Syrups are mostly used as vehicles in the linctuses. Tolu syrup is preferred in cough preparations due to its aromatic odor and flavour. Glycerol syrup and invert syrup are also used as vehicles. Linctus preparation for diabetic patients contain sorbitol syrup (vehicle). Medicament is first dissolved in little amount of water and then added into vehicle. Syrups are viscous and contain less amount of water, this limits (affects) the dissolution of medicament in syrup. 2. Additives: Colouring agents : Amaranth, Erythrosin, Tartrazine. Flavouring agents : ...