Viscosity &vVscometer

Viscosity Viscosity can be described as “ It is the internal resistance of the molecules of any liquid to flow called viscosity”. Viscosity is the fundamental tool to check the internal friction of any liquid, like water is thin so it has lower viscosity and on the other hand honey is thick so it has higher viscosity. Viscometers These are the specialized equipment and apparatus used for the determination of viscosity of different liquids. There are various types of viscometers the most famous are: 1) Ostwald viscometer or U-Tube viscometer 2) Rotational viscometer 3) Falling ball viscometer Factors affecting the viscosity Temperature Viscosity decreases with the increases in temperature Size of the molecule Viscosity increases with the increases in size of the molecule Molecular shape More irregular the liquid’s molecular shape greater would be the viscosity of the liquid. More regular shape of liquid’s molecule lesser would be the viscosity. Adhesive forces Stronger the adhesive forces greater would be the viscosity of the liquid. Cohesive forces Stronger the cohesive forces lesser would be the viscosity of the liquid. Application of Viscosity measurement 1) Viscosity determination is the fundamental quality control test for syrups, suspension thickness and consistency. 2) Viscosity is also given us the indication regarding quality and purity of liquid raw material 3) Viscosity tell us about the thickness of liquid substances 4) Viscosity determination is also a key quality control test for oil base injections and suspension. 5) Viscosity enhancers (e.g. Methylcellulose, Hydroxyethylcellulose) are used in ophthalmic solutions to increase their viscosity. This enables the formulation to remain in the eye longer and gives more time for the drug to exert its therapeutic activity or undergo absorption. viscosity, viscometers, types of viscometers/viscosimeter #ostwald viscometers(capillary viscometers), rotational viscometers, falling ball viscometers