Three Different Approaches Based on Derivative Ratio Spectra for Spectrophotometric Resolution of a Quaternary Mixture in Semisolid Dosage Form

Abstract

Background Recent incorporated spectrophotometer software supporting mathematical methods was considered as an optimum key for the resolution of multicomponent mixtures. Objective Several spectrophotometric techniques are introduced for the determination of mixtures of Tretinoin (TN), Hydroquinone (HQ), and Fluocinolone acetonide (FA), in presence of the preservative; Methyl Paraben (MP), without any separation procedure, taking into consideration the presence of two minor components and the severe overlap of their spectra. Methods Constant multiplication coupled spectrum subtraction resolved the quaternary mixture into the zero-order absorption spectrum of TN alone and a severely overlapped ternary mixture of HQ, FA, and MP. Three approaches based on the derivative ratio spectra were applied to resolve this ternary severely overlapped mixture which are: derivative ration zero-crossing point method, factorized derivative ratio method, and double divisor derivative ratio method. Results The work is conducted over a concentration range of 1–10, 4–38, and 4–35 µg/mL, for TN, HQ, and FA, respectively. The results obtained are compared statistically to each other and to the official methods showing no significant difference. Conclusions The proposed methods are successfully applied for the simultaneous determination of the three drugs in presence of MP in synthetic mixtures and in their combined dosage form Trimelasma® cream with very good accuracy and precision. Highlights Comparative study between conventional and new methods for resolving ternary severely overlapped mixtures. Mathematical manipulation steps and enrichment techniques aided accurate quantification of the minor components in mixture.

Utilizing two different sustainable and green spectrophotometric approaches using derivative ratio spectra for the determination of a ternary severely overlapped mixture: application to veterinary formulation

“…In this method [ 26 ], a combination containing X, Y and Z that show a severely overlapped spectra, is divided by one of the drugs’ standard solutions, and the DD1 of the resulted spectrum is found (the divisor component is removed by derivatization). To find the concentration of one component at the other component's zero-crossing point, modification is done in the matching regression equation by changing the peak amplitude.…”

“…The three-component mixture (X + Y + Z) is divided by (X + Y); an equimolar mixture, then followed by derivatization [ 26 ]. In this case, Cz concentration is directly proportional to the derivative at the coincidence points, which represent the minimum and maximum wavelength for pure Z, and Z in the ternary mixture (X + Y + Z).…”

“…Unfortunately, multicomponent mixtures, including this studied mixture, typically have highly overlapping spectra, which urged the buildup of various methods for determining each studied drug's concentration [ 25 ]. Recent incorporated spectrophotometer software that supports mathematical techniques is believed to be an optimal key to resolve complicated spectra, and to get as much analytical data as possible from the unresolved bands [ 26 ].…”