What is rheology in pharmacy?

Rheology is the science of flow and deformation of matter. Particularly gels and non-Newtonian fluids, which exhibit complex flow behavior, are frequently encountered in pharmaceutical engineering and manufacturing, or when dealing with various in vivo fluids.

What is the importance of rheology in pharmacy?

Rheological characterization tools, such as viscometers, allow drug producers to directly affect how a drug is formulated and developed, cutting across parameters and conditions to arrive at product characteristics that can be quantified.

What is meant by rheology in physical pharmaceutics?

Pharmaceutics, Pharmacy Notes. Rheology is the science which deals with flow of the liquid and deformation of the solid. The term 'rheology' was derived from the Greek words rheo (flow) and logos (science).

How do you explain rheology?

Rheology is a branch of physics that deals with the study of the flow of liquid matter and the deformation of solid materials. Rheology considers the non-Newtonian fluids that remains viscous or in a semi-solid state and the deformation of solids during the application of a certain amount of force.

What is rheology and its types?

In rheological measurements, three types of flow are often applied: the steady-state shear, dynamic shear, and external flow. The steady-state shearing is important for predicting processability and performance of polymer nanocomposites.

RHEOLOGY | PHYSICAL PHARMACY | PART-1 | VISCOSITY | FLUIDITY |

What is the importance of rheology?

Researchers believe that rheological characterization is essential for the development, optimization, and processing of foods. Food rheology also determines the food texture. Rheological flow properties deal with the perception of food when we touch or put it into our mouth.

What are the examples of rheology?

Many physiological materials and fluids exhibit complicated rheology. Within the eye, examples include the vitreous humour, the liquid in the tear film, and the blood in capillaries.

What is rheology and its application?

Rheology is science which treats the deformation and flow of materials. The science of rheology is applied to the physics, chemistry, engineering, medicine, dentistry, pharmacy, biology and so on. Classical theory of elasticity treats the elastic solid which is accordant to Hooke's law [ 1].

What is rheology measurement?

Measurement. Rheometers are instruments used to characterize the rheological properties of materials, typically fluids that are melts or solution. These instruments impose a specific stress field or deformation to the fluid, and monitor the resultant deformation or stress.

What is rheological fluid?

Fluid rheology is used to describe the consistency of different products, normally by the two components viscosity and elasticity. By viscosity is usually meant resistance to flow or thickness and by elasticity usually stickiness or structure.

What is rheology PDF?

Rheology is the study of the flow of matter, primarily in the liquid state, but also as 'soft solids' or solids under flow conditions in which they respond with plastic flow rather than deforming elastically in response to the applied force.

What is viscosity in physical pharmacy?

Viscosity is a measure of a fluid's resistance to flow i.e. the measure of a substance's resistance to motion under an applied force. A fluid with large viscosity resists motion because its molecular makeup gives it a lot of internal friction.

What is Rheopectic fluid?

Rheopectic fluids, such as some lubricants, thicken or solidify when shaken. The opposite and much more common type of behaviour, in which fluids become less viscous the longer they undergo shear, is called thixotropy. Examples of rheopectic fluids include gypsum pastes and printer inks.

What is fluid viscosity?

Viscosity is a measure of a fluid's resistance to flow.

A fluid with low viscosity flows easily because its molecular makeup results in very little friction when it is in motion. Gases also have viscosity, although it is a little harder to notice it in ordinary circumstances.

What is pharmacy thixotropy?

Thixotropy is the property exhibited by the pseudo plastic systems which exhibit the time-dependent change in the viscosity. Thixotropic systems demonstrate a decrease in viscosity with time under the constant shear.

What is rheology modifiers in cosmetics?

Rheology modifiers are often referred to as thickeners, and whilst increasing the apparent viscosity will confer a feeling of “quality” to the formulation, this is only one aspect of rheological control. The product itself can be Newtonian or pseudoplastic, thixotropic, be a ringing gel or a stringy flowable liquid.

What are the rheological properties?

The most common rheological properties are yield stress, relaxation times, viscosity and compliance. Rheological properties study the behavior of fluids under mechanical loading. The solid structure, having a defined shape, deforms and stresses when subjected to a load.

What is the difference between viscosity and rheology?

The key difference between rheology and viscosity is that rheology is the study of the flow of matter, whereas viscosity is a measure of its resistance to deformation. Rheology is a branch of physics or physical chemistry, while viscosity is a quantitative measurement that is useful in chemistry.

What is rheometer used for?

A rheometer is an instrument which characterizes the flow of a substance in response to forces, its rheology. A viscometer measures a fluid's resistance to deformation at a given rate. This gives a single parameter, viscosity, for the fluid.

Why is rheology important in cosmetics?

Rheological measurements provide information about storage stability, processability or flow properties of liquid and semi-solid formulations, which are essential for quality control and further product development.

Is rheology a physical property?

Rheology is the branch of physics in which we study the way in which materials deform or flowin response to applied forces or stresses. The material properties that govern the specific way in which these deformation or flow behaviors occur are called rheological properties.

What are rheological parameters?

The rheological parameters were viscosity (cp), torque%, shear stress (dyne/cm²) and shear rate (s^-1).

Which type of fluid is lipstick?

Thixotropic: Apparent viscosity for thixotropic fluids decreases with time under constant applied shear stress. Example: Crude oil, lipstick, certain paints, and Printing Ink.

What is an example of rheopectic fluid?

Examples include printer inks, gypsum pastes and the body's synovial fluids. A frequently quoted example of a rheopectic fluid is a mixture of corn starch (cornflower powder) and water. When at rest, the mixture can be stirred gently (so is relatively fluid) but will solidify instantly when hit with a fist or a hammer.

What is the difference between thixotropic and rheopectic fluids?

Some liquids behave differently with stress (application of force) over time. Rheopectic liquids increase in viscosity as stress over time increases. Thixotropic liquids decrease in viscosity as stress over time increases.