Simultaneous Spectrophotometric Determination of Cefixime and Moxifloxacin in Bulk Drug and Drug Formulation by Absorption Ratio Method

About Authors:
Shah Chirag K.*, Umalkar Deepak, Dr. Rajesh KS.
Parul Institute of Pharmacy, Gujarat University,
Waghodia-391760, Dist. Vadodara,
Gujarat, India.

The present manuscript described the simple, rapid, accurate, sensitive, precise and economical Q- absorption ratio method for simultaneous determination of Cefixime and Moxifloxacin in combined tablet dosage form. Absorption ratio method uses the ratio of absorbances at selected wavelengths, one which is isoabsorptive point and other being the λmax of the one of the components. Cefixime and Moxifloxacin shows isoabsorptive point at 275nm in 0.1N HCl. The second wavelength used is 295nm, which is λmax of Moxifloxacin. The concentrations of the drugs were determined by using ratio of absorances at isoabsorptive point and at λmax of Moxifloxacin. The method successfully applied to the Pharmaceutical formulation because no interference from the tablet formulation excipients was found. The results of analysis have been validated statistically and by recovery studies.

Reference Id: PHARMATUTOR-ART-1355

Cefixime Trihydrate (CEF), (6R,7R)-7-{[2-(2-amino-1,3-thiazol-4-yl)-2-(carboxy methoxyimino)acetyl]amino}-3-ethenyl-8-oxo-5-thia 1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic trihydrate (Figure 1), is third generation Cephelosporin antibiotic1. Moxifloxacin (MOX), 1-cyclopropyl-7-[(1S,6S)-2,8-diazabicyclo[4.3.0]non-8-yl]-6-fluoro-8-methoxy-4-oxo-quinoline-3-carboxylic acid(Figure 2), is floroquinolone antibiotic2. This combination is used for treatment of lower Respiration tract infection in adult3. Literature reveals Spectrophotometric4, HPLC8 methods for Cefixime in Pharmaceutical dosage forms and as well as biological fluids. Literature survey also reveals Spectrophotometric14 and HPLC18 methods for Moxifloxacin in Pharmaceutical dosage forms and as well as biological fluids. The combination is not official in any pharmacopeia; hence no official method is available for the estimation of Cefixime and Moxifloxacin in their combined dosage forms. Literature survey does not reveal any simple spectrophotometric or other method for simultaneous estimation of Cefixime and Moxifloxacin in combined dosage forms. The present work describes simple, sensitive, rapid, accurate and economical spectrophotometric method for simultaneous estimation of both the drugs in their combined tablet dosage forms.

Material and Method:
A Shimadzu model 1800 double beam UV/Visible Spectrophotometer with spectral width of 2nm, wavelength accuracy 0.5nm and a pair of 10nm matched quartz cell was used to measure absorbance of all the solutions. Spectra were obtained automatically from UV-Probe ver2.34 software.

Reagents and Materials:
Cefixime powder was gifted by Kaptab Pharmaceuticals, Vadodara, India. Moxifloxacin powder was gifted by BDR Pharmaceutical International Pvt. Ltd., Mumbai, India. HCl AR Grade was procured from SDFCL, Baroda, India.

Preparation of the standard stock solution:
An accurately weighed quantity of CEF (10 mg) and MOX (10 mg) were transferred to a separate 100 ml volumetric flask and dissolve and diluted to the mark with 0.1N HCl. To obtain standard solution having concentration of Cef (100 μg/ml) and Mox (100 μg/ml).

The Absorption Ratio method based on measurements at two wavelengths. Two dissimilar chromophores must necessary have different powers of light absorption at some points or in linear absorption. A set of two simultaneous equations obtained by using mean absorptivity values are given below. Seven working solution having concentration 2, 4, 6, 8, 10, 12 and 14 μg/ml of both the drug Cefixime and Moxifloxacin were prepared respectively in 0.1N HCl and the absorbance at 275nm (Isoabsorptive point) and 295nm(λmax of Moxifloxacin) were measured and absorptivity coefficients were calculated using calibration curve. The absorbance and absorptivity at this wavelength were substituted in following equations to obtain the concentration of both drugs. From overlain spectra Fig3.

Cx = Qm - Qy  X (A1/Ax1) ……………(1)
         Qx - Qy  

Cy = Qm - Qx  X (A1/Ay1) ……………(2)
         Qy - Qx

QM, QX, and QY were obtained as below:
QM = A2/A1, QX = ax2/ax1, QY = ay2/ay1

Where, A1 and A2 were absorbance of sample at 275 nm and 295 nm respectively, ax1 and ax2 are absorptivity of Cefixime at 275 nm and 295 nm, ay1 and ay2 are absorptivity of Moxifloxacin at 275 nm and 295 nm. Validity of above framed equation was checked by using mixed standard of pure drug sample of two drugs, measuring their absorbance at respective wavelength and calculating concentration of two components. Results of which are reported in Table.3



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