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Novel spectrophotometric method for determination of cinacalcet hydrochloride in its tablets via derivatization with 1,2-naphthoquinone-4-sulphonate.

Darwish IA, Al-Shehri MM, El-Gendy MA - Chem Cent J (2012)

Bottom Line: The precision of the method was satisfactory; the values of relative standard deviations (RSD) did not exceed 2%.The results were compared favorably with those of a reference pre-validated method.The method is practical and valuable in terms of its routine application in quality control laboratories.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P,O, Box 2457, Riyadh 11451, Saudi Arabia. idarwish@ksu.edu.sa.

ABSTRACT
This study represents the first report on the development of a novel spectrophotometric method for determination of cinacalcet hydrochloride (CIN) in its tablet dosage forms. Studies were carried out to investigate the reaction between CIN and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. In alkaline medium (pH 8.5), an orange red-colored product exhibiting maximum absorption peak (λmax) at 490 nm was produced. The stoichiometry and kinetic of the reaction were investigated and the reaction mechanism was postulated. This color-developing reaction was employed in the development of a simple and rapid visible-spectrophotometric method for determination of CIN in its tablets. Under the optimized reaction conditions, Beer's law correlating the absorbance with CIN concentration was obeyed in the range of 3 - 100 μg/ml with good correlation coefficient (0.9993). The molar absorptivity (ε) was 4.2 × 105 l/mol/cm. The limits of detection and quantification were 1.9 and 5.7 μg/ml, respectively. The precision of the method was satisfactory; the values of relative standard deviations (RSD) did not exceed 2%. No interference was observed from the excipients that are present in the tablets. The proposed method was applied successfully for the determination of CIN in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 100.80 - 102.23 ± 1.27 - 1.62%. The results were compared favorably with those of a reference pre-validated method. The method is practical and valuable in terms of its routine application in quality control laboratories.

No MeSH data available.


Absorption spectra of CIN against water (1), NQS against water (2), and their reaction product against reagent blank (3).
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Figure 1: Absorption spectra of CIN against water (1), NQS against water (2), and their reaction product against reagent blank (3).

Mentions: The absorption spectrum of CIN was recorded against water (Figure 1). It was found that CIN exhibits two maximum absorption peaks (λmax) at 235 and 320 nm, and the molar absorptivities (ε) at these wavelengths were 5.1 × 104 and 1.7 × 104 l/ml/cm, respectively. Because of the blue shifted λmax of CIN, its determination in the pharmaceutical formulations based on the direct measurement of its absorption for ultraviolet light is susceptible to potential interferences from the co-extracted excipients. Therefore, derivatization of CIN to a more red-shifted derivative was necessary. CIN contains secondary amino group for which many chromogenic reagents are available for color-producing reactions. These reactions include formation of colored charge-transfer complex with electron acceptor [16], formation of ion-pair associates with pairing reagents [17-19], and formation of condensation product with a chromogenic reagent [20]. These methods are usually associated with some major drawbacks such as laborious multiple extraction steps in the analysis by ion-pair based methods [17-19], or in preparation of the free base of the drug prior to the analysis by charge-transfer-based methods [16], and long reaction time, thus the procedure is time-consuming [20]. Darwish et al. [21-24] has demonstrated that NQS is a valuable color-developing reagent in the development of simple spectrophotometric methods for the determination of many pharmaceutical amines in the form of their acid salts. For these reasons, the present study was devoted to investigate the reaction between NQS and CIN, and employed this color reaction in the development of a new simple and rapid spectrophotometric method for determination of CIN in its tablets. The reaction between CIN and NQS was performed, and the absorption spectrum of the reaction product was recorded against reagent blank. The product was orange red-colored exhibiting λmax at 490 nm (Figure 1). Obviously, the λmax of CIN-NQS derivative was red-shifted from the underivatized CIN by 171 nm. As well, the value of ε (sensitivity) was greatly enhanced to be 4.2 × 105 l/mol/cm. The following paragraphs describe the optimization of the reaction conditions.


Novel spectrophotometric method for determination of cinacalcet hydrochloride in its tablets via derivatization with 1,2-naphthoquinone-4-sulphonate.

Darwish IA, Al-Shehri MM, El-Gendy MA - Chem Cent J (2012)

Absorption spectra of CIN against water (1), NQS against water (2), and their reaction product against reagent blank (3).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3295732&req=5

Figure 1: Absorption spectra of CIN against water (1), NQS against water (2), and their reaction product against reagent blank (3).
Mentions: The absorption spectrum of CIN was recorded against water (Figure 1). It was found that CIN exhibits two maximum absorption peaks (λmax) at 235 and 320 nm, and the molar absorptivities (ε) at these wavelengths were 5.1 × 104 and 1.7 × 104 l/ml/cm, respectively. Because of the blue shifted λmax of CIN, its determination in the pharmaceutical formulations based on the direct measurement of its absorption for ultraviolet light is susceptible to potential interferences from the co-extracted excipients. Therefore, derivatization of CIN to a more red-shifted derivative was necessary. CIN contains secondary amino group for which many chromogenic reagents are available for color-producing reactions. These reactions include formation of colored charge-transfer complex with electron acceptor [16], formation of ion-pair associates with pairing reagents [17-19], and formation of condensation product with a chromogenic reagent [20]. These methods are usually associated with some major drawbacks such as laborious multiple extraction steps in the analysis by ion-pair based methods [17-19], or in preparation of the free base of the drug prior to the analysis by charge-transfer-based methods [16], and long reaction time, thus the procedure is time-consuming [20]. Darwish et al. [21-24] has demonstrated that NQS is a valuable color-developing reagent in the development of simple spectrophotometric methods for the determination of many pharmaceutical amines in the form of their acid salts. For these reasons, the present study was devoted to investigate the reaction between NQS and CIN, and employed this color reaction in the development of a new simple and rapid spectrophotometric method for determination of CIN in its tablets. The reaction between CIN and NQS was performed, and the absorption spectrum of the reaction product was recorded against reagent blank. The product was orange red-colored exhibiting λmax at 490 nm (Figure 1). Obviously, the λmax of CIN-NQS derivative was red-shifted from the underivatized CIN by 171 nm. As well, the value of ε (sensitivity) was greatly enhanced to be 4.2 × 105 l/mol/cm. The following paragraphs describe the optimization of the reaction conditions.

Bottom Line: The precision of the method was satisfactory; the values of relative standard deviations (RSD) did not exceed 2%.The results were compared favorably with those of a reference pre-validated method.The method is practical and valuable in terms of its routine application in quality control laboratories.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P,O, Box 2457, Riyadh 11451, Saudi Arabia. idarwish@ksu.edu.sa.

ABSTRACT
This study represents the first report on the development of a novel spectrophotometric method for determination of cinacalcet hydrochloride (CIN) in its tablet dosage forms. Studies were carried out to investigate the reaction between CIN and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. In alkaline medium (pH 8.5), an orange red-colored product exhibiting maximum absorption peak (λmax) at 490 nm was produced. The stoichiometry and kinetic of the reaction were investigated and the reaction mechanism was postulated. This color-developing reaction was employed in the development of a simple and rapid visible-spectrophotometric method for determination of CIN in its tablets. Under the optimized reaction conditions, Beer's law correlating the absorbance with CIN concentration was obeyed in the range of 3 - 100 μg/ml with good correlation coefficient (0.9993). The molar absorptivity (ε) was 4.2 × 105 l/mol/cm. The limits of detection and quantification were 1.9 and 5.7 μg/ml, respectively. The precision of the method was satisfactory; the values of relative standard deviations (RSD) did not exceed 2%. No interference was observed from the excipients that are present in the tablets. The proposed method was applied successfully for the determination of CIN in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 100.80 - 102.23 ± 1.27 - 1.62%. The results were compared favorably with those of a reference pre-validated method. The method is practical and valuable in terms of its routine application in quality control laboratories.

No MeSH data available.