karthik rheology
-
Upload
karthik-ramineni -
Category
Documents
-
view
235 -
download
0
Transcript of karthik rheology
-
8/6/2019 karthik rheology
1/19
RESEARCH ON RHEOLOGY
R.Karthik
PA/2010/09 1
-
8/6/2019 karthik rheology
2/19
Topics covered
SelectionofPectin as pharmaceuticalexcipient on the basis of
Rheological behavior
Determinationofoptimal combinationofsurfactants in
creams using rheology measurements
Rheological investigationofSelfEmulsificationprocess
Rheological analysis ofstabilityofpharmaceutical suspensions
2
-
8/6/2019 karthik rheology
3/19
The aim ofthis study was to evaluate rheological properties of pectin solutions
to determine the influence of polymer concentration, pH, preservatives and
heating duration on viscosity, using Brookfield R/S Plus Rheometer. The
results shows that dilute pectin solutions are showing Newtonian, but at a
moderate concentration they exhibit the non-Newtonian behavior, and the
psudoplastic nature was found to increase with concentration. As the pH of
the polymer solution lowered there was increase in viscosity of the system
observed, this may be due do the carboxyl acid groups on the pectin chains
are neutralize i.e. reduction in ionization, and leads to reduction in hydration
of the carboxylic acid groups. As a result of reduced ionisation, thepolysaccharide molecules do not repel each other over their entire length. The
result shows that pectin solutions are stable at broad range of pH. It was
observed that as the temperature or pH of the system increases there was
decrease in viscosity.
SelectionofPectinaspharmaceuticalexcipient on
the basisofRheological behavior
3
-
8/6/2019 karthik rheology
4/19
4
-
8/6/2019 karthik rheology
5/19
5
-
8/6/2019 karthik rheology
6/19
6
-
8/6/2019 karthik rheology
7/19
7
-
8/6/2019 karthik rheology
8/19
8
-
8/6/2019 karthik rheology
9/19
9
-
8/6/2019 karthik rheology
10/19
10
-
8/6/2019 karthik rheology
11/19
11
-
8/6/2019 karthik rheology
12/19
Purpose. Aimofthestudyistoexploretheviscoelastic propertiesofintermediate
liquidcrystalline (LC) phaseformedduring self-emulsification and toevaluate its
influenceon self-emulsification
performance.
Methods. Binarysystemoftween 80 (T80)andimwitor 742 (I742)was used and
different SES werepreparedwith I742 at 10, 30,50,70 and 90% w/w concentration
levels. Self-emulsificationwas monitored byvisualobservations anddroplet size
measurement. Mesophases obtained by50% v/v aqueous hydrationofSESwere
utilizedfor polarizing microscopy,differential scanning calorimetry and rheologicalstudies.
RheologicalinvestigationofSelfEmulsificationprocess
12
-
8/6/2019 karthik rheology
13/19
Results
SES 30% presented good emulsifying properties and nano-size dropletswere observed after its emulsification as compared to micron sized droplets for
other SES. In polarizing microscopy, formation of intermediate LC phase was
observed in all SES. Lamellar phase was evident in 30% SES while other SES
exhibited micellar cubic phase. Presence ofhigh level ofstructurally bound water
in thermal analysis confirmed mesophase formation in all SES. Thus, rheological
studies concluded presence of weak and fragile mesophase structure in 30% SES
while LC phase structure with little structural build up was observed in other SES.
This weak mesophase structure in SES 30% presented no or very little resistance
against strain induced deformation. Therefore, during emulsification, weak
mesophase in SES 30% ruptured with ease and released jet of nano-size droplets
compared to coarse droplets for other SES.
13
-
8/6/2019 karthik rheology
14/19
compliance= strain/stress
14
-
8/6/2019 karthik rheology
15/19
Rheologicalanalysisofstabilityofpharmaceutical
suspensions
Viscometry: The samples were exposed to increasing stress (0.1-100 Pa) and relation
between shear stress and shear rate was studied.
Oscillation stress sweep: Linearviscoelastic region (LVR) was determined
in the stress range of0.1-100 Pa at aconstant frequency (1 Hz). The ability of
hydrated SES to resist the deformation with applied stress was recorded in terms of
trends of elastic modulus (G) and loss modulus (G).
Oscillation frequency sweep: The samples were exposed to increasing frequency (0.1-
10 Hz) at a constant stress in LVR. Effect of frequency on G, G, phase degree () and
loss tangent (tan ) were recorded.
Creep-recovery: SES samples were exposed to a constant stress in LVR for
100s. It was then instantly removed and the recovery was followed for 200s. The creep
compliance, J (defined as ratio between measured strain and applied stress) was
recorded against time.
15
-
8/6/2019 karthik rheology
16/19
Shear stress
16
-
8/6/2019 karthik rheology
17/19
References
Rheological EvaluationofSilicon/Carbopol Hydrophilic GelSystems as a Vehicle
for DeliveryofWater Insoluble Drugs Giulia Bonacucina,1 Marco Cespi,1 Monica Misici-Falzi,
and Giovanni F. Palmieri1,2
Rheological InvestigationofSelf-emulsification Process
Shailesh V. Biradar, Ravindra S. Dhumal, Anant Paradkar
Department ofPharmaceutics,Bharati Vidyapeeth University, Poona CollegeofPharmacy,
Erandwane, Pune 411 038, Maharashtra State, India
SELECTION OF PECTIN AS PHARMACEUTICAL EXCEPIENT ONTHE BASIS OF RHEOLOGICAL
BEHAVIOR RAJENDRA AWASTHI Laureate InstituteofPharmacy, Kathog 177101, (Teh. Dehra, Dist. Kangra,
HP), India
Rheological Analysis oftheStabilityofPharmaceuticalSuspensions
Eva-Maria Kutschmann, Gebrder Haake, Dieselstrasse4, D - 76227 Karlsruhe
17
-
8/6/2019 karthik rheology
18/19
18
-
8/6/2019 karthik rheology
19/19
19