Fig. 9.

Principal component loading vectors of the three principal components and second derivative spectra of the pure components. The spectrum of PC 1, which accounted for 91 % of the total variance was similar to the spectrum of pure letrozole while PC 2, which accounted for 8 % of the total variance was similar to the spectrum of PLGA. PC 3, which accounted for 1 % of the total variance had a spectrum which was not similar to spectra of both letrozole and PLGA and may be due to variation in other physical properties such as particle size, intensity differences, or differences in packing densities