The ability of the HPLC method to separate all closelyeluted compounds and excipients from HMPHA bandwas calculated by assessing resolution (Rs) and separationfactor (α). The tailing factor and column efficiency forHMPHA was also assessed. Column resolution (Rs) andseparation factor (α) were calculated by using equation,Rs=2(Rta-Rtb)/(WA+Wb), and (α)=(Rtb–tm)/(Rta–tm), where Rta, Rtb are retention times and Wa, Wb areband width of peak A and B in chromatogram. For aprecise and rugged HPLC analysis resolution of 1.5 andsymmetry factor less than 1.5 are required (11,14)