UV Spectrophotometric Method for Determination of Cinitapride in Pure and its Solid Dosage Form

A new, rapid, precise, accurate and sensitive analytical method was developed for the UV spectrophotometric assay of cinitapride (CTP). The drug obeyed the Beer’s law and showed good correlation. It showed absorption maxima at 260 nm in methanol. The linearity was observed between 5-40 μg mL. The results of analysis were validated by recovery studies. The recovery was more than 99%. The proposed method is the only method available for spectrophotometric determination of the drug. It is simple, precise, sensitive and reproducible and can be used for the routine quality control testing of the marketed formulations.


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

Reagents
CTP was tested for purity by measuring its melting point and IR spectra and no impurities were found.Methanol used were of analytical grade.

Standard solutions
Standard stock solution of CTP (1000 µg mL -1 ) was prepared in methanol.It was further diluted to obtain 5, 10, 20, 30 and 40 µg mL -1 with methanol.The absorbance was measured at 260 nm against methanol as blank.The calibration curve was plotted in the concentration range of 5 to 40 µg mL -1 of CTP in methanol.

Procedure for tablets
Twenty tablets were weighed accurately and triturated to fine powder.The powder equivalent to 10 mg CTP was weighed and transferred to 25 mL volumetric flask.To this 15 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 20 µg mL -1 concentration and the absorbance measured at 260 nm against methanol as a blank.

Results and Discussion
The UV spectrum of standard solutions of CPT 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 CPT are shown in Table 2.

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

Stability
The standard stock solutions of CPT 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 CPT is highly stable in the mentioned conditions.

Linearity and range
In developed UV method, calibration curve was linear in the range from 5 to 40 µg mL -1 of CPT.

Inter-day precision
This was done by analyzing formulation by same analyst 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.

Accuracy
To ensure the accuracy and reproducibility of the results obtained, known amounts of pure drug was added to the previously analysed formulated samples and these samples were reanalyzed by the proposed method and also performed recovery experiments.The percentage recoveries thus obtained were given in Table 3.

Conclusions
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 CPT showed no interference from the common excipients.Hence, these methods could be considered for the determination of CPT in the quality control laboratories.

Table 1 .
Optical characteristics of proposed method.

Table 2 .
Assay results and precision studies.