UV Spectrophotometric Determination of Aripiprazole in Bulk and Pharmaceutical Formulation

A simple, sensitive and reproducible spectrophotometric method was developed for the determination of aripiprazole in pure form and in pharmaceutical formulation. It has an absorption maximum at 219 nm and obeys beer’s law in the concentration range 210 μg mL. Results of analysis were validated statistically and by recovery studies. The apparent molar absorptivity and sandell’s sensitivity were 5.2 x 10 L mol cm and 8.4 x 10 μg cm, respectively. The slope and intercept of the equation of the regression line are 0.0035 and 0.1155 respectively. Correlation coefficient was found to be 0.9998. This method is successfully employed for the determination of aripiprazole in pharmaceutical preparation.


Experimental
The spectrophotometric measurements were carried out using An Elico UV/Visible double beam spectrophotometer SL-164 with 1 cm matched quartz cells.

Reagents
Aripiprazole was tested for purity by measuring its melting point and IR spectra and no impurities were found.Analytical grade methanol was used.A pharmaceutical preparation of aripiprazole was obtained from local pharmacy.

Standard solutions
Standard stock solution of aripiprazole (1000 µg mL -1 ) was prepared in methanol.It was further diluted to obtain 2, 4, 6, 8 and 10 µg mL -1 with methanol.The absorbance was measured at 219 nm against methanol as blank.The calibration curve was plotted in the concentration range of 2 to 10 µg mL -1 of aripiprazole in methanol.

Procedure for tablets
Twenty tablets were weighed accurately and triturated to fine powder.The powder equivalent to 100 mg aripiprazole was weighed and transferred to 100 mL volumetric flask.To this 50 mL of methanol was added and sonicated for 15 minutes, then filtered through Whatman No. 42 filter paper.The residues were washed thoroughly with methanol and further diluted with methanol to 6 µg mL -1 concentration and the absorbance measured at 219 nm against methanol as a blank.

Results and Discussion
The UV spectrum of standard solutions of aripiprazole in methanol was illustrated in Figure 2. The optical characteristics such as Beer's Law limit, molar absoptivity, Sandell's sensitivity, slope and intercept are summarized in Table 1.The assay and precision studies results for tablets containing aripiprazole are shown in Table 2.

Validation
The assay of aripiprazole was validated with respect to stability, linearity, precision and accuracy.

Stability
The standard stock solutions of aripiprazole were stored, in two different conditions, at ±4 0 C and at ambient temperature for one month.During this period, the solutions were analyzed with UV spectrophotometric method, the spectrum was compared with the spectrum of daily prepared standard solution, and no difference was obtained between them.It is decided that aripiprazole is highly stable in the mentioned conditions.

Linearity and range
In the developed UV method, calibration curve was linear in the range from 2 to 10 µg mL -1 of aripiprazole.

Precision
Inter-day precision: This was done by analyzing formulation for six days subsequently.The % RSD values are shown in Table 2.

Intra-day precision
This was done by analyzing formulation in same day for six times of individual preparation and observation.The % RSD and datas are shown in Table 2.

Recovery Studies
Recovery studies were carried out by adding a known quantity of pure drug to a preanalysed formulations and the proposed method was followed.The results of analysis and recovery studies are presented in Table 3.The percentage recovery values indicated that there is no interference from the excipient(s) present in the formulation.The developed method found to be sensitive, accurate, precise and most reproducible and can be used for the routine quality control analysis of aripiprazole in bulk drug and its formulation.

Conclusion
The proposed method is found to be rapid, precise, accurate and sensitive.The statistical parameters and recovery study data clearly indicate the reproducibility and accuracy of this method.Analysis of the authentic sample containing aripiprazole showed no interference from the common excipients.Hence, these methods could be considered for the determination of aripiprazole in the quality control laboratories.

Table 2 .
Assay results and precision studies.
*Mean of six determinations.