Introduction to Study of Consolidation studies, Effect of Diffusion Parameters Presented by G. Sai Navitha Department of Pharmaceutics

1. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 1
A Seminar as a part of curricular requirement for
I year M. Pharm I semester
Presented by
G.Sai Navitha
(Reg. No.20L01S0303)
Dept. Of Pharmaceutics
Under the guidance of
Dr. Pavan Kumar Chintamaneni M.Pharm, Ph.D.
Associate Professor & Head
Department of Pharmaceutics
Study of Consolidation studies
Effect of Diffusion Parameters

2. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 2
• Introduction
• Higuchi model
• Applications
• Reference
Contents

3. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 3
What is meant by consolidation?
Consolidation is an increase in mechanical strength of material
resulting from particle-particle interactions.
What is meant by diffusion?
It is the movement of drug molecules in to & within the biological
environment. It involves several process of drug transport across
the cell membranes.
Introduction

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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 4
Higuchi proposed this model in 1961 .
This model is based on the hypotheses that
i. Initial drug concentration in the matrix is much higher than drug
solubility;
ii. Drug diffusion takes place only in one dimension
iii. Drug particles are much smaller than system thickness
iv. Matrix swelling and dissolution are negligible
v. Drug diffusivity is constant and
vi. Perfect sink conditions are always attained in the release
environment.
Higuchi model

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K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 5
Accordingly , model expression is given by this equation:
Q=A
Where
Q is the amount of drug released in time t per unit area A,
C is the drug initial concentration,
Cs is the drug solubility in the matrix media and
D is the diffusivity of the drug molecules
A is the concentration of drug present in matrix per unit volume.
Higuchi model

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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 6
This is valid during all the time, except when the total depletion of
the drug in the therapeutic system is achieved.
To study the dissolution from planer heterogenous matrix system,
where the drug concentration in the matrix is lower than solubility
and the release occurs through pores in the matrix, in the expression
is given by the below equation.
ft=Q= [D / (2C - CS)CSt]1/2
Where
D is the diffusion coefficient of the drug molecule in the solvent,
is the porosity of the matrix
Higuchi model

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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 7
is the tortuisity of the matrix
Q,A, CS and t have meaning assigned above.
• In general way it is possible to simplify the Higuchi model as
Q=KHt1/2
Where
Q is cumulative amount of drug release at time
KH is Higuchi constant,
t is time in hours
The Higuchi equation suggests that the drug release by diffusion.
Higuchi model

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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 8
The data obtained were plotted as cumulative percentage drug release
versus square root of time
Higuchi model

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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 9
 By using this model dissolution of drug from several modified release
dosage forms like some transdermal system and matrix tablet with
water soluble drugs are studied
Applications

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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 10
• C.V.S.Subramanyam , “Text book of Physical Pharmaceutics”, 2nd
edition , Vallabh Prakashan.
• Bruschi , M.L. (2015) “ Mathematical models of drug release” in
strategies to modify the drug release from pharmaceutical
systems.Elsevier BV.
• Shaikh H.K., Kshirsagar R.V and Patil S.G., 2015.Mathematical
models for drug release characterization: a review world j pharm
pharmacent sci, 4
References

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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 11