Experimental design application and interpretation in pharmaceutical technology - Computer-Aided Applications in Pharmaceutical Technology - page 50

stabilization, followed by the complexation with the γ -cyclodextrin
form of the vitamin, the preparation method (dried reconstituted
vesicles - DRV or multilamellar vesicle - MLV), sonication type,
and molar ratio of cholesterol as signifi cant factors.

Example 4

The Plackett-Burman design was used to model the effect of
Polyox-Carbopol blends on drug release (El-Malah and Nazzal,
2006). The aim of the study was to screen the effect of 7
factors - Polyox molecular weight and amount, Carbopol, lactose,
sodium chloride, citric acid, and compression force on
theophylline release from hydrophilic matrices. A Plackett-Burman
experimental design of 12 experiments was performed to
investigate the effects of 7 factors. A polynomial model was
generated for the response, cumulative amount of theophylline
released after 12 h, and validates using ANOVA and residual
analysis. Results showed that only the amounts of Polyox and
Carbopol polymers have signifi cant effects on theophylline release.
Regular Plackett-Burman design for 7 factors requires 8
experiments. In the presented study, 12 experimental runs were
performed, where additional runs allow derivation of regression
equations, since some of information from experiments can be
used for error estimation. Note that if there are 8 experiments,
there are 8 degrees of freedom - one for each of the factors and
one for the intercept of the equation.

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Example 5

Experimental design was used to optimize drug release from a
silicone elastomer matrix and to investigate transdermal drug
delivery (Snorradóttir et al., 2011). Diclofenac was the model drug