Chitosan Loaded Mucoadhesive Microspheres of Gliclazide - Journal

Prakash Rao B et al./ Formulation and Evaluation of Mucoadhesive Buccal Drug Delivery System of Metoprolol Tartrate by Using Central Composite Design
Table 3:Result of bioadhesive strength and release parameter obtained for formulations by CCD
RUN CARBOPOL HPC BIOADHESIVE DRUG RELEASE T50%
STRENGTH AFTER 8 HOUR
F-1 65 65.0 36.62 69.41 5.02
F-2 65 65.0 33.45 64.85 4.97
F-3 15.50 65.0 32.95 68.00 4.52
F-4 65 65.00 33.25 64.25 4.95
F-5 30 30.00 32.88 87.90 4.25
F-6 30 100.00 38.02 68.09 5.15
F-7 100 30.00 35.72 67.95 5.11
F-8 100 100.00 43.52 60.45 6.46
F-9 65 65.00 36.23 65.54 5.35
F-10 114.50 65.00 47.14 65.41 5.55
F-11 65 15.50 34.55 85.78 4.17
F-12 65 114.50 45.06 68.66 5.65
F-13 65 65 33.65 65.68 5.25
with water the gel formation of polymers occurs which acts as
rate controlling matrix for the release of drug molecules
(Salamone, 1996). In this case, effect of both polymers can be
explained by mathematical equation in terms of actual
factors:
R 1 = + 115.03476 - 0.29224*A - 0.92256*B + 2.51224E-
2 2
003*A*B + 1.33265E-004*A + 4.42510E-00* B
The quadratic model is selected for this response with Model
F-value 10.79 and p value is 0.0035. Both the factor A,
carbopol and B, HPC decreases drug release from the tablets.
HPC is a semi synthetic polymeric derivative of cellulose, will
swell in an aqueous medium to form a gel like matrix that
controls release by acting as a barrier to drug dissolution and
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diffusion (Park C. R, 2002). HPC shows the higher
controlling effect on the release of drug than the carbopol due
to formation of higher viscous solution. Whereas high
molecular weight carbopol is polymer of acrylic acid
crosslinked with polyalkenyl ethers or divinyl glycol polymer
which is hydrophilic in nature and swells faster and greater
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extent at pH 6-7 due to carboxylate group on the polymer
backbone ionise, resulting in repulsion between negative
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charges (pharmainfo.net). So, the carbopol promotes the
penetration of the dissolution medium into tablet matrix and
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results in greater release of drug as it do not dissolve in water .
(Fig. 5) represents the observed response values compared to
that of predicted values. The effect of A and B can be further
elucidated with the help of response surface plot (Fig 6).
Higher release of metoprolol tartrate was found after 8 hours
in low concentrations of both polymers. At high level of B the
percentage release of MT at 8 hours was low. From the results,
it can be concluded that both the independent variables have
Fig. 5: Correlation between actual and predicted values
for In vitro drug release at 8 hours
Fig. 6: Response surface plot showing the effect of factor
A (Carbopol) and factor B (HPC) on in vitro drug release at 8 hours
150 RJPS, Jul - Sep, 2011/ Vol 1/ Issue 2