UV Spectrophotometric Method Validation of Rosuvastatin Calcium in API and Pharmaceutical Dosage Form

Rosuvastatin calcium (ROS) is a statin class of drug that is widely prescribed as anti-hyperlipidemic drug.¹ It belongs from BCS class II which exhibits poor aqueous solubility and has molecular formula of C₄₄H₅₄CaF₂N₆O₁₂S₂. Rosuvastatin calcium decrease cholesterol levels in blood and advised to treat dyslipidaemia. Calcium bis[(3R,5S,6E)-7-{4-(4-fluorophenyl)-6-isopropyl-2-[methyl(methylsulfonyl)amino]-5-pyrimidinyl}-3,5-dihydroxyhept-6-enoate] is the IUPAC nomenclature for rosuvastatin calcium. It reduces LDL (low-density lipoprotein) cholesterol, triglycerides, overall cholesterol, and protein B in blood. Additionally, ROS slightly raises levels of HDL (high-density lipoprotein) in blood. These steps are crucial for lowering the possibility of atherosclerosis, that can result in a number of cardiovascular disorders including peripheral vascular disease, heart attacks, and strokes.^2,3

Fig 1: Structure of Rosuvastatin Calcium

Rosuvastatin calcium has, as far as we know, been measured using spectrophotometric techniques. The current study outlines a quick, precise, perceptive, and consistent UV-spectroscopic approach for estimating amount of rosuvastatin calcium in bulk and marketed tablet.

MATERIALS AND METHODS

Instrumentation

UV- visible Spectrophotometer (Shimadzu 1900i) which have two identical quartz cells of path length 1 cm and equipped with UV probe software were utilized to record spectra and determine the absorbance for this research work.

Materials Required

Rosuvastatin Calcium (pure drug) was purchased. Rosuvastatin Calcium commercial tablets (Rozavel 10) were acquired from the local store. From Loba Chemie Pvt. Ltd., sodium chloride, sodium phosphate dibasic, monobasic potassium phosphate (MKP) was obtained. The remaining chemicals employed in investigation were of analytical quality. Analytical-grade methanol was utilized as the solvent.

Phosphate buffer Preparation at different pH

28.80 grams of sodium phosphate dibasic and 11.5 grams of monobasic potassium phosphate were dissolved in an adequate amount of distilled water. Then volume make up was done up to 1000 ml to obtain pH 6.8.^4,5

2.38 grams of sodium phosphate dibasic, 0.19 grams of monobasic potassium phosphate, and 8 grams of sodium chloride were dissolved in appropriate amount of purified water. Subsequently, final volume had been acclimatized to 1000 ml in order to achieve pH 7.4.⁶

Calibration Curve for Rosuvastatin Calcium Pure Drug

To make the primary stock solution, 10 mg drug was dissolved in different buffer solutions. 10 mg pure drug had been dissolved in 100 ml Methanol: Phosphate buffer (pH 6.8) (10:90 v/v) and 10 mg pure drug was dissolved in 100 ml Methanol: Phosphate buffer (pH 7.4) (10:90 v/v) to get concentration 100 µg/ml (Stock 1). Then from stock solution small amount of samples had been collected in different volumetric flasks, adulterated to 10 ml, for acquiring a range of 2–20 µg/ml and then analysed to obtain their corresponding wavelength. The UV-visible spectrophotometer (Shimadzu 1900i, Japan) was used to scan the solutions for the detected wavelengths in the 200-400 nm range for analysis. It was determined that the wavelength in both pH 6.8 and 7.4 phosphate buffer was 240 nm.⁷

Preparation of Sample

10 commercial tablets of Rosuvastatin calcium (Rozavel 10) had been precisely weighed and grinded as fine powder. The powder that is equal to 10 mg of rosuvastatin calcium had been precisely weighed. The sample's stock solution was made by dissolving it in Methanol: Phosphate buffer solution (10:90 v/v) at pH 6.8 and 7.4. To get concentration range of 2–20 µg/ml, an aliquot was collected from each buffer solution and diluted up to 10 ml in a volumetric flask. At the appropriate wavelength, the prepared solution's absorbance was measured.

Method Validation

According to the standards set out by the International Council for Harmonization (ICH), process developed was validated for linearity, precision, limit of detection (LOD), and limit of quantification (LOQ).

Linearity

From the primary stock solution, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, and 2.0 ml had been transferred to various volumetric flasks and volume make up was done using a buffer solution at pH values of 6.8 and 7.4, respectively. A concentration of 2–20 µg/ml of Rosuvastatin Calcium was observed.

Precision

Intraday precision and interday precision evaluations were used to assess accuracy of the provided method. Analysis of three distinct solutions with three varied concentration range (8, 12, and 16 μg/ml) was done, and the results of the analysis were reported as a percentage of the relative standard deviation (% RSD).

Limit of Detection and Limit of Quantification

LOD refers to smallest concentration which is identifiable with statistical significance by means of a given analytical procedure. LOQ stands for the lowest analyte concentration which can be accurately and precisely standardized with reliability. LOD and LOQ are crucial for method validation and determining the sensitivity of an analytical method. They have been determined with the help of a calibration curve, by calculating standard deviation of response and slope of curve of standard and test sample, and then employing the formulas shown below:

LOD = 3.3 × (σ/s)

LOQ = 10 × (σ/s)

Where ‘σ’ indicates standard deviation of intercept and ‘s’ indicates slope of calibration curve.⁸

RESULT AND DISCUSSION

Absorption Maxima Method

A 10 μg/ml solution of rosuvastatin calcium had been made through appropriately diluting a conventional stock solution. It was checked in spectrum mode between 400 to 200 nm to determine analytical wavelength.  λ_max of 240 nm (Fig 2) was chosen for analysis from the spectrum of rosuvastatin calcium. The calibration curve was generated at 240 nm with concentrations ranging in 2-20 μg/ml. Concentration for sample solution had been ascertained using calibration curve.

Fig 2: Absorption maxima of Rosuvastatin Calcium

Method Validation

The goal of this work was to develop a novel spectrometric technique for rosuvastatin calcium analysis in API and marketed tablet.

Table 1. Linearity Data of Rosuvastatin Calcium in Pure Drug and Marketed Sample

Fig 3. Calibration curve of pure Rosuvastatin Calcium and marketed tablet (Rozavel 10) in different buffer solution respectively

Table 2. Intraday Precision of Rosuvastatin Calcium (Pure Drug) at pH 6.8

Table 3. Intraday Precision of Rosuvastatin Calcium (Pure Drug) at pH 7.4

Table 4. Interday Precision of Rosuvastatin Calcium (Marketed Sample) at pH 6.8

Table 5. Interday Precision of Rosuvastatin Calcium (Marketed Sample) at pH 7.4

Table 6. Assay for Rosuvastatin Calcium Average (n=6)

Table 7: Detection and quantification data of Rosuvastatin Calcium (API) and marketed sample (Rozavel 10)