Estimation of Levocetirizine in Bulk and Formulation by First Order Derivative Area under Curve UV-Spectrophotometric Methods

Simple, fast and reliable spectrophotometric methods were developed for determination of Levocetirizine in bulk and pharmaceutical dosage forms. The solutions of standard and the sample were prepared in Methanol. The quantitative determination of the drug was carried out using the second order Derivative Area under Curve method values measured at 235-243 nm. Calibration graphs constructed at their wavelengths of determination were linear in the concentration range of Levocetirizine using 5-25μg/ml (r2=0.9994) for first order Derivative Area under Curve spectrophotometric method. The proposed methods have been extensively validated as per ICH guidelines. There was no significant difference between the performance of the proposed methods regarding the mean values and standard deviations. The developed methods were successfully applied to estimate the amount of Levocetirizine in pharmaceutical formulations.


Introduction
Chemically Levocetirizine is [2-[4-[(r)-(4chlorophenyl) phenylmethyl]-1-piperazinyl] ethoxy] acetic acid is a third generation non-sedative antihistamine, developed from the second generation antihistamine cetirizine. [1,2] It is the L enantiomer of the cetirizine racemate. Levocetirizine works by blocking histamine receptors. It does not prevent the actual release of histamine from mast cells, but prevents it binding to its receptors. [3,4] This in turn prevents the release of other allergy chemicals and increased blood supply to the area, and provides relief from the typical symptoms of hay fever. In our Literature survey reveals that for Levocetirizine Spectrophotometric [5,6] methods and HPLC [7-9] methods have been reported for its determination in commercial formulation.
To our notice, no UV-spectrophotometric method using First Order Derivative Area under Curve has been reported for the determination of Levocetirizine in bulk and tablets.Hence an attempt has been made to develop new First Order Derivative Area under Curve spectrophotometric method for estimation of Levocetirizine in bulk and pharmaceutical formulations with good accuracy simplicity, precision and economy.

Derivative Spectrophotometric Methods:-
The First derivative spectrophotometry was used in the wavelength ranges from 235 and 243 nm.
[dA/dλ= f(λ ): first order The First derivative spectrum of an absorption band is characterized by a maximum, a minimum, and a cross-over point at the λ max of the absorption band. [ Where, α is area of portion bounded by curve data and a straight line connecting the start and end point, β is the area of portion bounded by a straight line connecting the start and end point on curve data and horizontal axis, λ1 and λ2 are wavelength range start and end point of curve region. [14][15][16]

Apparatus and instrumentation:-
A shimadzu 1800 UV/VIS double beam spectrophotometer with 1cm matched quartz cells was used for all spectral measurements. Single Pan Electronic balance (CONTECH, CA 223, India) was used for weighing purpose. Sonication of the solutions was carried out using an Ultrasonic Cleaning Bath (Spectra lab UCB 40, India). Calibrated volumetric glassware (Borosil®) was used for the validation study.

Assay of tablet formulation:-
Twenty tablets each containing 5 mg of Levocetirizine were weighed crushed to powder and average weight was calculated. Powder equivalent to 10 mg of Levocetirizine was transferred in 100 ml of volumetric flask. A 50 ml of Methanol was added and sonicated for 15 minutes. Then solution was further diluted up to the mark with Methanol. The solution was filtered using Whatmann filter paper no. 41, first 5 ml of filtrate was discarded. This solution was further diluted to obtain 10µg/mL solution with water, subjected for UV analysis using Methanol as blank. This procedure was repeated three times.

Method Validation
The above method was validated for various parameters such as Accuracy, Linearity, Precision, Limit of detection (LOD) and Limit of Quantitation (LOQ) according to ICH guideline.

Accuracy
The accuracy for the analytical method was evaluated at 80%, 100% and 120% levels of 25µg/ml Sample solution. First Order Derivative Area under curve (AUC) was measured in wavelength range 235-243 nm and results were obtained in terms of percent recovery. Three determinations at each level were performed and % RSD was calculated for each level. www.ssjournals.com

Precision:-
The precision of an analytical procedure expresses the closeness of an agreement (degree of scatter) between a series of measurements obtained from multiple sampling of the same homogeneous sample under the prescribed conditions intraday precision was studied by integrating area of standard solution of 25µg/ml concentration at six independent series in the same day. Interday precision studies were performed by integrating area of standard solution of 25µg/mlconcentration on three consequent days. The % RSD Was calculated.

Limit of Detection and Limit of Quantification:-
The Limit of Detection (LOD) is the smallest concentration of the analyte that gives the measurable response. LOD was calculated using the following formula LOD = 3.3 σ /S The Limit of Quantification (LOQ) is the smallest concentration of the analyte, which gives response that can be accurately quantified. LOQ was calculated using the following formula LOQ = 10 σ/S Where, σ is standard deviation of the response and S is the slope of the calibration curve. LOD & LOQ of Levocetirizine was found to be 0.64µg/ml &1.93 µg/ml respectively.

Results and Discussion
The UV visible spectroscopic method for the Levocetirizine by First order derivative Area under Curve was found to be simple, accurate, economical and reproducible. The drug concentrations were found to be linear in the range of 05-25 µg/ml and the correlation coefficient value of 0.9994 indicates that developed method was linear. For Precision the percent relative standard deviation (% RSD) was found to be 0.3698 while, intra-day and inter-day precision results in terms of percent relative standard deviation values were found to be 0.9351 and 0.9257 respectively thus the method is observed as precise. The accuracy of the method was assessed by recovery studies at three different levels i.e. 80%, 100%, 120%. The values of standard deviation were satisfactory and the recovery studies were close to 100%. The % RSD value is ≤ 2 indicates the accuracy of the method. The Limit of Detection and Limit of Quantitation values were found to be 0.64 µg/ml & 1.93µg/ml respectively. The result of the analysis for pharmaceutical formulation by the developed method was consistent with the label claim, highly reproducible and reliable. The method can be used for routine quality control analysis of Levocetirizine in bulk and pharmaceutical formulations.

Conclusion
The UV spectroscopic AUC method for the analysis of Levocetirizine by First order derivative Area under Curve was found to be simple, precise, and www.ssjournals.com accurate; can be used for assay of bulk drug and pharmaceutical dosage formulations.