SIMULTANEOUS ESTIMATION OF MOXIFLOXACIN HCl AND BROMFENAC SODIUM IN EYE DROPS BY SPECTROPHOTOMETRIC METHODS

SIMULTANEOUS ESTIMATION OF MOXIFLOXACIN HCl AND BROMFENAC SODIUM IN EYE DROPS BY SPECTROPHOTOMETRIC METHODS

P. J. Vyas*, J. B. Dave and C. N. Patel

Department of Quality Assurance, Shri Sarvajanik Pharmacy College, Mehsana-384001, Gujarat, India

ABSTRACT

Moxifloxacin Hydrochloride is a fluorinated quinolone antibacterial and Bromfenac Sodium is a non-steroidal anti-inflammatory. The combination formulation is used for the treatment of the reduction of post operative inflammatory conditions of the eye. Three new, simple, accurate and precise UV spectrophotometric methods have been developed and validated for the simultaneous determination of Moxifloxacin Hydrochloride (MOX) and Bromfenac Sodium (BROM) in their combined dosage forms. Method - I is based on simultaneous equation method using two wavelengths, 294 nm (λmax of MOX) and 265 nm (λmax of BROM). Method - II Q‐absorption Ratio method using two wavelengths, 294 nm (λmax of MOX) and 276.66 nm (Isoabsorptive point). Method - III involves the use of First order derivative technique. Here 301.71 nm, the zero crossing point of Bromfenac Sodium, was selected for the determination of Moxifloxacin Hydrochloride and 293.22 nm, the zero crossing point of Moxifloxacin Hydrochloride, was selected for the determination of Bromfenac Sodium. Methanolic HCL (0.1 M) was the solvent used in all three methods. Moxifloxacin showed linearity in the range of 1-14 μg/ml and Bromfenac showed linearity in the range of 1-14 μg/ml in all the methods. All methods were validated statistically and recovery studies were carried out. All methods were found to be accurate, precise and reproducible. These methods were applied to the assay of the drugs in marketed formulation, which were found in the range of 98.0% to 102.0% of the labelled value for both Moxifloxacin and Bromfenac. Hence, the methods herein described can be successfully applied in quality control of combined pharmaceutical dosage forms.

First order derivative method

INTRODUCTION:Moxifloxacin Hydrochloride is 1-Cyclopropyl- 6- fluoro- 8- methoxy- 7- [(4aS, 7aS)-octa hydro- 6H- pyrrolo[3, 4b] pyridin- 6- yl]- 4- oxo-1, 4-dihydroquinoline-3-carboxylic acid hydrochloride ¹. It is a prescription drug indicated for the treatment of bacterial infections. Moxifloxacin is a broad-spectrum antibiotic that is active against both Gram-positive and Gram-negative bacteria. It functions by inhibiting DNA gyrase, a type II topoisomerase, and topoisomerase IV, enzymes necessary to separate bacterial DNA, thereby inhibiting cell replication ^{2, 3, 4}. Bromfenac Sodium is Sodium [2-amino-3-(4-bromobenzoyl) phenyl] ⁵. It acts thought to block prostaglandin synthesis by inhibiting cyclooxygenase 1 and 2. Prostaglandins have been shown mediators of certain kinds of intraocular inflammation.

Prostaglandins have been shown to produce disruption of the blood-aqueous humor barrier, vasodilation, increased vascular permeability, leukocytosis, and increased intraocular pressure ^{5, 6}. The chemical structures of MOX and BROM are shown in Fig. 1(A) (B).

FIG. 1: CHEMICAL STRUCTURE OF (A) MOXIFLOXACIN HYDROCHLORIDE; (B) BROMFENAC SODIUM ^{1, 5}

A detailed survey of analytical literature for MOX revealed several methods based on varied techniques, viz, HPLC ^{7, 8, 9, 10}, Spectrophotometry ^{11, 12}, High‐ Performance Thin‐ Layer Chromatography (HPTLC) ^{13, 14}. Similarly, a survey of the analytical literature for BROM revealed methods based on HPLC for determination in pharmaceuticals ^{15, 16}.

According to detailed survey of analytical literature none of the reported analytical procedures describes a simple and satisfactory UV spectrophotometric method for simultaneous determination of MOX and BROM in their combined dosage forms. So the objective of this work was to develop simple, precise and rapid spectrophotometric methods for combination drug products containing MOX and BROM.

MATERIALS AND METHODS:

Instrumentation: A Shimadzu model 1700 (Japan) double beam UV-Visible spectrophotometer with spectral width of 2 nm, wavelength accuracy of 0.5 nm and a pair of 10 mm matched quartz cell was used to measure absorbance of all the solutions. Spectra were automatically obtained by UV-Probe system software (UV Probe version 2.31).

An Electronic analytical balance (Acculab) and an ultrasonic bath were used in the study.

Materials and reagents: MOX and BROM bulk powder was gifted by Zydus Cadila Health Care Pvt. Ltd., Ahmadabad, india and Enaltec lab Pvt. Ltd., Mumbai, india respectively. The commercial fixed dose combination product was procured from the local market. Methanol AR Grade and Hydrochloric acid AR Grade were procured from S.D.Fine Chemicals Ltd., Mumbai, India.

Standard and Test Solutions:

Preparation of standard solution: An accurately weighed quantity of MOX (10 mg) and BROM (10 mg) were transferred to a separate 100 ml volumetric flask and dissolved and diluted to the mark with Methanolic HCL to obtain standard solution having concentration of MOX (100 μg/ml) and BROM (100 μg/ml).

Preparation of test solution: From the Opthalmic formulation ,4- Quin brom (0.5 % w/v MOX & 0.09 % w/v BROM), 1.1 ml taken in  100 ml volumetric flask and the volume was adjusted to mark with methanolic HCl. This was working sample solution having strength 55 μg/ml of MOX & 10 μg/ml of BROM.

Methods:

Simultaneous Equation Method: In this method, seven working standard solutions having concentration 2-14 μg/ml for MOX and 1-13 μg/ml for BROM were prepared in Methanolic HCL and the absorbance at 294 nm (λ-max of MOX) and 265 nm (λ-max of BROM) were measured and absorptivity coefficients were calculated using calibration curve.

The concentration of two drugs in the mixture can be calculated using following equations