Table 6 The advantages and disadvantages of each proposed spectrophotometric method.

I. Third derivative spectrophotometry^40,41,42

- Time saving, cheap, simple, more environmentally friendly, shows reliability, precision, accuracy and could be used for routine analysis of the cited drugs.

- Strong dependence on instrumental parameters and its tendency to amplify noise, leading to distorted spectra.

II. Ratio difference method^43,44

- Simplicity, accuracy and reproducibility

- The ability to solve severely overlapped spectra without prior separation, meanwhile, it doesn’t require any sophisticated apparatus or computer programs.

- Requires appropriate divisor spectrum that should compromise between minimal noise and maximum sensitivity

III. First derivative of ratio spectrophotometric method⁴³

- Good selectivity for components with overlapping spectra

- Useful in multicomponent analysis

- The multiple manipulating steps: division, then calculating the derivative.

IV. Induced dual wavelength method^25,45

- It is good for application to a binary mixture having completely overlapped zero-order absorption spectra

-Need no divisor.

- Requires precise two wavelength selection

- Need calculation of the equality factor (F).

V. Dual wavelength resolution technique⁴⁵

- Recovering the original spectra of the cited drugs which act as the spectral profile of them.

-Enhances the sensitivity of the results using measurements at peak maxima.

-Must be used complementary to another spectrophotometric method such as Induced Dual Wavelength Method.