Chitosan Loaded Mucoadhesive Microspheres of Gliclazide - Journal

again weighed and recorded. Followed by 2 trials were done.
Then the average of initial weights and final weights were
recorded.
initial weight - Final weight
% Friability = ---------------------------------------- * 100
Initial weight
In-vitro Mucoadhesive Strength Measurement
Porcine buccal mucosa was obtained from local slaughter
house and stored in Kreb's buffer solution. The experiment
was performed within the 3 hours of procurement of mucosa.
The porcine mucosa was washed with the distilled water and
carefully tied to the glass slide with the help of cyanoacrylate
adhesive and placed in petridish. Kreb's solution was added
into the petridish up to the upper surface of the buccal mucosa
to maintain buccal mucosal viability during the experiment.
During the experiment the solution was maintained at 37°C.
The tablet was stuck on to the glass stopper by using
cyanoacrylate adhesive. The preload of 20 gm was placed on
the glass stopper for 7 minutes to establish the adhesion
bonding between tablet and porcine buccal mucosa. The
preload and preload time were kept constant for all
formulations. The preload was removed from stopper and
water was added in to beaker from separating funnel at a
constant rate of 100 drops per minute (Fig 1). The addition of
the water was stopped when the tablet was removed from
porcine buccal mucosa. The weight of water collected in
5
beaker was weighed which is taken as mucoadhesive strength .
In-vitro Dissolution Studies
The dissolution studies of the buccoadhesive tablet was
performed in 900 ml of phosphate buffer (pH=6.8) using the
USP type II dissolution apparatus under sink condition at 37
0
± 0.2 C and 50 rpm. At the appropriate time interval, the
sample was withdrawn and volume made up with distilled
water. The samples were filtered through a 0.45 µm Millipore
filter and amount of MT which was released determined
spectrophotometrically at 274 nm and the release data were
17
evaluated kinetically .
Glass Stopper
Buccal Tablet
Buccal mucosa
Prakash Rao B et al./ Formulation and Evaluation of Mucoadhesive Buccal Drug Delivery System of Metoprolol Tartrate by Using Central Composite Design
Fig. 1: Schematic diagram of in-vitro bioadhesive
strength measurement device
Separating Funnel
148
Analytical Method
Accurate weight of powder equivalent to 50 mg metoprolol
tartrate was taken and transferred in to 100 ml volumetric
flask and volume was made up with distilled water. The
powder solution was transferred in 250 ml of beaker and
heated for 30 minutes for the extraction of the drug. Then, the
solution was cooled and filtered. The samples were diluted
appropriately and the absorbance was measured at 274 nm
using the Shimadzu (model 1601) UV- visible
16
spectrophotometer.
Regression Analysis
The response parameters were statistically analyzed by
applying one way ANOVA at 0.05 levels using commercially
available software Design-Expert software (Stat-Ease Inc,
Minneapolis, USA). The individual parameters were
evaluated using the F test and Linear, 2FI, Quadratic models
were generated for each response parameter using the
multiple linear regression analysis (MLRA) equation:
2 2 2 2
R = b 0 + b 1 A+ b2B + b3AB + b4A + b5B + b6AB + b7A B (1)
Where, R is the level of measured response, b 0 is the intercept
of the arithmetic mean response of the 13 runs, A and B are
the coded level of the independent variables. The AB is the
interaction term, show how response changes when two
2 2
factors are simultaneously used. A , B are quadratic terms of
the independent variables to evaluate the nonlinearity.
Kinetic release Studies
For the determination of the drug release kinetics from the
buccal tablet, the in vitro release data were analyzed by zero
order, first order, Higuchi and Korsmeyer and Peppas
17
equations .
Zero order release Kinetic
To study the zero order release kinetics the release data was
fitted into the Following equation:
dQ/dt = K (2)
0
Where, 'Q' is the amount of drug release, 'K ' is the zero order
0
release rate constant and 't' is the release time. The graph is
plotted percentage cumulative drug release (%CDR) verses
time.
First Order Release Kinetic
To study the first order release kinetics the release rate data are
fitted into the following equation:
dQ/dt = K Q (3)
1
Where, 'Q' is the fraction of drug release, 'K ' is the first order
1
release rate constant and't' is the release time. The graph is
plotted log %CDR remaining verse time.
RJPS, Jul - Sep, 2011/ Vol 1/ Issue 2