Rheology

Question 1

Rheology

Answer 1

is the science which deals with flow of liquids and deformation of solid
-science concerned with the deformation of matter under the influence of stress.
-The flow of simple liquids can be described by viscosity, an expression of the resistance
to flow; however, other complex dispersions
cannot be simply expressed by viscosity.

Question 2

manufacturing of dosage form

Answer 2

-materials undergo process such as mixing, dlowing through pipes, filling into the containers
-flow related changes influene the slection of mixing equipmenthan

Question 3

handling of drugs for administation

Answer 3

the syringibility of the medicines, the pouring of the liquids from containers, extusion of ointment from tubes, all depend on the changes in flow behaviour of dosage form

Question 4

importance of rheology

Answer 4

-formulation of medicinal and cosmetic creams, pastes and lotions
-formulation of emulsions, suspentions, suppositories, and tablet coating
-fluidity of solutions for injection
-extrusion of paste from tube
-in mixing and flow of materials, their packaging into the containers, their removal prior to use, the pouring from the bottle
-passage of the liquid to a syringe needle
influence the choice of processing equiptments in pharmaceutical system

Question 5

rheolgy can affect

Answer 5

-patients acceptibility of the product
-physical stability
-biological availibility
-absorption of drugs
-in the gastrointestinal tract

Question 6

viscocity

Answer 6

it is defined as resistance to the flow
n=F/G
where F= shearing stress
G=rate of shear
n= coefficiant of viscocity

Question 7

flow

Answer 7

newtonian
non-newtonian: pseudoplastic, plastic, dialatant

Question 8

newtonian system

Answer 8

those materical which follow newton law of flow are called newtonian flow

Question 9

newtonian law of flow

Answer 9

it states that
“the shear stress is directly proportional to the rate of hear strain”

Question 10

shear stress

Answer 10

ratio of shear force to the cross sectional area required for flow

Question 11

rate of shear strain

Answer 11

defined as change in velocity (dv) b/w two planes (layer) of liquid which is separated by distance (dv)

Question 12

example of newtonian fluids

Answer 12

water
benzene
ethyl alcohol
and true solutions and solutoons of simple molecules

Question 13

kinematic viscocity

Answer 13

it is the ratio of viscocity of fluid to its density
v=n/p
where,
n= viscocity of fluid
p= density of fluid
v=kinetic viscocity
it is a measure of the resistive flow of the fluid under influence of gravity

Question 14

effect of temperature

Answer 14

viscocity is highly dependant on temp in case of liquid, viscocity decreases wih increases in temp
temp increases= viscocity decreases

in case of gas- viscotity increasing with increase in temperature