A seminar on

Presented by

Modh Sudipkumar c.

PA /2010 /11

Industrial Aspect

of Rheology

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Rheology is Responsible for any formulation, production, appearance, usage, and finally affect stability

Affects final cost of product

Class I recalls of Fentanyl Reservoir patches from Innovator and generic manufacturers

In short………If a material is pumped, sprayed, extended, extruded, molded, coated, mixed, chewed, swallowed, rubbed, transported, stored, heated, cooled, aged …RHEOLOGY is important ….!!

Introduction

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contents

Viscometer vs. Rheometer

Types of the viscometer used in industry

Characteristics

Application of viscometer in stability and evaluation

Rheology: A Rapid Screening Method for Testing Stability

Latest types of viscometers and Rheometers

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Viscometer vs. Rheometer

• Viscometer: instrument that measures: viscosity over a limited shear rate range

• Rheometer: instrument that measures:

• Viscosity over a wide range of shear rates, and…• Viscoelasticity of fluids, semi-solids and solids

http://pioneer.netserv.chula.ac.th/~sanongn1/course.html

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Types of the viscometer used in industry:

Capillary viscometerFalling sphere viscometerCup and bob viscometercone and plate viscometer

How will you choose appropriate viscometer?

•Newtonian types of fluids shear rate directly proportional to shear stress•Instrument are operated at single shear rate can be used

-Capillary viscometer-Falling sphere viscometer

but these give erroneous result

•Non Newtonian types of fluids shear rate not directly proportional to shear stress•Instrument are operated at variety of shear rate can be used

-Cup and bob viscometer-cone and plate viscometer

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Characteristics:Capillary viscometerExp Ostwald viscometerBased on poiseuille’s equationAccording to US pharmacopeia capillary apparatus used for high viscous methyl cellulose type of solution

Falling sphere viscometerExp hoeppler viscometer

Cup and bob viscometerExp Couette type

McMichael searle typeRoto viscometerBrookfield viscometer(rotational type of viscometer)

cone and plate viscometerExp ferranti-shirley

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Application of viscometer in stability and evaluation:

1) Polaxomer vehiclesUsed in tear solution for treating “dry eye syndrome “For evaluation computer controlled couette viscometer is used

2) SuppositoriesRelease and absorption is depend on rectal temperature, Brookfield viscometer is used study characteristic of triglycerides base at various temperature

3) EmulsionStabilized with triethanolamine stearate at various temperatureBrookfield viscometer is used

4) cosmetic sticksFerranti-shirley cone plate viscometer used

Physical pharmacy by martin page 581-582

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5) Tablet Excipient

Microcrystalline cellulose is used as granulating agentMixture torque rheometer is used to measure torque changes as water is added

6)Lamination *

process of lamination various stagesa) softening point of the resin -resin starts to soften and flow as elastic materialdrops of viscosity (~107 poise down to 100 to 5000 poise)

b) material is most fluid, and reaction rates start to increase as viscosity starts to build as the resin starts to gel. at gel point tan delta is oneparallel plate Rheometer+ is used

*Focus on Rheology By Arlon, Materials for Electronics, Inc.

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+parallel plate Rheometer:

upper plate is attached to transducer to measure torque resulting from strain upon the sample

system computer compares material stress to input strain and determines tan delta

or phase angle along with the storage and loss modulus components

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7)Suspensions

Settling of particles by Brookfield viscometer fitted with helipath attachment Consists of rotating T bar spindleDial reads resistance at various levels of suspension

8)Ointment

Consistency measured by Burrell severs Rheometer with helipath attachmentOintment is loaded into a cylinder and extruded with measured force Amount extruded is measurement of consistency

9)Aerosol

Viscosity is measured by Brookfield viscometer

10)Paste

capillary extrusion viscometer for the viscosity measurement of fish protein paste

Journal compilation © 2008 Wiley Periodicals, Inc.

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capillary extrusion viscometer

Rheology: A Rapid Screening Method for Testing Stability

• To understand rheology of viscoelastic fluids, frequency dependence of their G'and G" material functions to be measured

shear storage modulus G'

shear loss modulus G“

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http://pioneer.netserv.chula.ac.th/~sanongn1/course.html

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An oscillatory (sinusoidal)deformation (stress or strain)is applied to a sample.

the material response(strain or stress) is measured.

The phase angle δ, or phaseshift, between the deformationand response is measured.

G’

G”

shear storage modulus G' shear loss modulus G“

http://pioneer.netserv.chula.ac.th/~sanongn1/course.html

ideal solid, elastic Tan delta= 0º high viscosity

Newtonian fluid Tan delta= 90º low viscosity

• The ratio of G"/G', known as tandelta is predictive parameter for studying the storage stability of suspensions

• single rheological test can rapidly predict the stability of a drug suspension by monitoring the value of a well-defined parameter tan delta#

Tan delta= G"/G'

• *http://www.pharmaceutical-int.com/article/rapid-screening-methods.html

• # http://ciks.cbt.nist.gov/~garbocz/SP946/node11.htm

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Tan delta

16

Latest types of viscometers and Rheometers

1)HAAKE RheoStress 6000 (2007)1

Universal Rheometervariety of temperature control unitstemperatures ranging from -80 up to 500°C

2) Brookfield viscometes2

1© 2007/10 Thermo Fisher Scientific Inc. ·2 Achieving the Basics in Viscosity Measurement to Comply with 21CFR Part 11

By Len Thibodeau Rheometer

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Significance of Helipath Stand

substances with yield values unsuitable for viscosity or consistency measurements with rotational viscometersrotating spindle, be it cylinder, disc, or paddle, will create channel Produce negligible and meaningless torque

The Brookfield Helipath™ Stand is designed to slowly lower or raise rotating T-bar spindle By always cutting into fresh material, the problem of channelling or separating is eliminated

http://www.brookfieldengineering.com/products/accessories/helipath-stand.asp

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3) Interfacial Shear Rheometer

KSV NIMA

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Interfacial Shear Rheometer

Viscoelastic films relationships are nonlinear

intermediate between purely viscous and purely elastic responses in industry and in

biologicals

To define product stability in different industries such as food, petrochemical, cosmetics,

and pharmaceuticals

Application:

Prediction of emulsion, froth and foam stability

Determination of thin film structure

Examination of phase transitions

Real time monitoring of surface reactions

Continuous monitoring of molecule adsorption into interfaces

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4) STRESSTECH

Where flow characteristic of a material determines its processibility, performance,and/or consumer acceptance.

Rheological instrumentation for the characterization of polymers-BY STEVEN M. COLO,

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I never did anything worth doing by accident, nor did any of my inventions come by accident; they came by work

- Thomas Alva Edison

I'm a great believer in luck, and I find, the harder I work, the more I have of it.

-Thomas Jefferson

Thank u………