1. INTRODUCTION:

Rosuvastatin calcium is chemically N3O6S)2Ca, a member of the class of statins, is the calcium salt of (E)-7-[4- (4-fluorophenyl) -6-isopropyl-2- [methyl (methyl sulfonyl) amino] pyrimidin-5-yl] (3R,5S)-3,5-di hydroxyhept-6-enoic acid. is HMG Co-A reductase inhibitor which is useful in management of increased lipid level. It increases the number of
hepatic Low Density Lipoprotein (LDL) receptors on the cell surface to enhance uptake and catabolism of LDL. Rosuvastatin calcium also inhibits hepatic synthesis of Very Low Density Lipoprotein (VLDL) which reduces the total number of VLDL and LDL. Rosuvastatin calcium acts by inhibiting the activity of 3hydroxy3 methylglutarylcoenzyme A (HMGCoA) reductase, the ratelimiting enzyme that converts 3-hydroxy-3- methylglutaryl coenzyme A to Mevalonate, a precursor of cholesterol.^1-4

2. MATERIALS:

2.1 Instrument: Absorbance was measured, and the Spectra was recorded over the wavelength of 200-400 nm using a double beam UV- Spectrophotometer Jasco V-630.

2.2 Materials: Rosuvastatin Calcium was obtained as a gift sample from Enaltec Labs, Methanol, Distilled water and other reagents were of analytical grade.

3. METHOD:

3.1 Preparation of Stock solutions

Standard Rosuvastatin Calcium 10 mg was weighed and dissolved in 5 mL of methanol in a 100 ml volumetric flask. The flask was shaken and volume was made up to the mark with distilled water to prepare a solution containing 100 µg / ml (stock solution A).^6,7

3.2 Selection of analytical concentration ranges

From the standard stock solution A of Rosuvastatin Calcium, appropriate aliquots were pipetted out into 10 ml volumetric flasks and dilutions were made with distilled water to obtain working standard solutions of concentrations from 2 to 100 μg / ml. Absorbance for these solutions were measured at absorption maxima at 242.8 nm. For the standard solution analytical concentration range were found to be 8 -32 µg / ml and those values were reported in Table no. 2.^6,7

3.3 Calibration curve for the Rosuvastatin Calcium (8 – 30 µg / ml)

Appropriate volume of aliquots from standard Rosuvastatin Calcium stock solution A were transferred to different volumetric flasks of 10 ml capacity. The volume was adjusted to the mark with distilled water to obtain concentrations of 8, 12, 16, 20, 24, 28 and 32 µg / ml. Absorbance spectra of each solution against distilled water as blank were measured at 242.8 nm and the graphs of absorbance against concentration were plotted and shown in Figure 1. The regression equation and coefficient of determination was determined.^6,7

3.4 Sample preparation for determination of Rosuvastatin Calcium from dosage form

Ten tablets of a brand were weighed and finely powdered. The powder equivalent to 10 mg of Rosuvastatin Calcium was accurately weighed and transferred to volumetric flask of 100 ml capacity containing 5 ml of the methanol and sonicated for 5 min. The flask was shaken and volume was made up to the mark with distilled water to give a solution of 100 µg / ml (stock solution B ). The above solution carefully filtered through Whatmann filter paper (No. 41) and used for the estimation of Rosuvastatin Calcium. To examine the absence of either positive or negative interference of excipients used in formulation, recovery studies were carried out.^6,7

4. VALIDATION METHOD:

4.1 Accuracy

Accurately weighed formulation sample equivalent to 10 mg of sample were mixed with 10 mg of Rosuvastatin Calcium pure drug. From above equivalent 20 mg mixture 10mg equivalent weight of sample were dissolved in 5 ml of methanol and further volume make up with distilled water. Solutions were analyzed.⁵

4.2 Precision

The parameter was validated by assaying number of aliquots samples of Rosuvastatin Calcium and its validity was estimated using parameters such as Standard deviation and Relative Standard deviation.⁵

4.3 Recovery Studies

5. RESULT AND DISCUSSION:

5.1 Determination of wavelength and calibration graph

The λmax of Rosuvastatin Calcium was found to be 242.8 nm in methanol and distilled water. The absorbance was measured at 242.8 nm against methanol and distilled water. The calibration curve was prepared by plotting absorbance versus concentration of drug.

5.2 Determination of Molar Absorptivity

Absorptivity constant is the ratio of the absorbance of the sample of the product of the thickness of the medium and concentration of the sample. Increase or decrease in absorbance depends upon Increase or decrease in concentration which always remain constant. The absorbance of different concentrations was determined at 242.8 nm and molar absorptivity calculated using following formula,

a= A/ bc

Where,

a= Absorptivity

A= Absorbance

b= Path length

c= Concentration

5.3 Effect on Absorbance with Time (Stability)

The stability of sample was checked by taking absorbance at regular interval of time. Absorbance remains stable for 320 min. than the absorbance decreased with time.

6. CONCLUSION:

The validation study shows that the developed UV method is accurate, rapid, precise, reproducible and inexpensive with acceptable correlation co-efficient, RSD (%) and standard deviations which make it versatile and valuable for determination of Rosuvastatin calcium in bulk or pharmaceutical dosage form. The advantages lie in the simplicity of sample preparation and the low costs of reagents used. From the results, it can be concluded that the proposed method for the estimation of Rosuvastatin Calcium is simple, convenient, accurate, sensitive and reproducible. It can be successfully used for routine analysis of the Rosuvastatin Calcium in bulk and pharmaceutical dosage forms.

Table no. 1: Optical Characteristics of Rosuvastatin Calcium

Parameters	Results
Absorption maximum	242.8 nm
Beer’s law limit (μg / ml)	8-32 (μg / ml)
Correlation coefficient (r²)	0.9830
Regression equation (y = mx + c) Slope (m) Intercept (c)	y =0.0258x + 0.0434 0.0258x 0.0434

Table no. 2: Results of calibration curve at 242.8 nm for Rosuvastatin Calcium by UV spectroscopy

Sr. no Concentration Absorbance

(µg / ml) (nm)

1 08 0.2745

2 12 0.3276

3 16 0.4537

4 20 0.5567

5 24 0.6784

6 28 0.7236

7 32 0.8543

Table no. 3: Accuracy results of Rosuvastatin Calcium at 242.8 nm

Amount of Sample (µg / ml)	Amount of Drug Added (µg / ml)	Amount recovered (µg / ml)	% Recovery ± SD
10	8	17.88	99.33
20	10	29.86	99.53
30	12	41.69	99.26

Table no. 4: Precision results of Rosuvastatin Calcium at 242.8 nm

Conc. Inter-day % RSD Intra-day %RSD

μg / ml Absorbance** Absorbance**

8 0.2745 ± 0.2176 0.0072 0.2739 ± 0.2324 0.0132

12 0.3276 ± 0.1254 0.0167 0.3277 ± 0.3246 0.0142

16 0.4537 ± 0.2785 0.0134 0.4522 ± 0.3316 0.0138

20 0.5567 ± 0.2545 0.0143 0.5576 ± 0.3468 0.0161

24 0.6784 ± 0.2172 0.0169 0.6781 ± 0.2122 0.0166

28 0.7236 ± 0.3241 0.0176 0.7233 ± 0.3165 0.0143

32 0.8543 ± 0.2768 0.0165 0.8538 ± 0.2467 0.0157

Table no. 5: Ruggedness results of Rosuvastatin Calcium at 242.8 nm

Analyst

Label Claim

Amount found

% Recovery ± SD

Analyst I

19.80

99.00 ± 0.66

Analyst II

19.91

99.95 ± 0.72

7. REFERENCES:

1. Nissen S, Nicholls S, Sipahi I, Libby P, Raichlen JS, Ballantyne CM. Effect of very high intensity statin therapy on regression of coronary atherosclerosis: The Asteroid Trial. JAMA. 295(13); 2006; 1556 1565.

2. Lennernas H, Fager G. Pharmacodynamics and pharmacokinetics of the HMGCoA reductase inhibitors. Clinical Pharmacokinetics. 32; 1997; 403425.

3. Indian Pharmacopeia, The Indian Pharmacopeia commission, 2007, volume 3, 1676-1678.

4. Remington, The Science and Practice of Pharmacy, Wolters Kluwer Health Pvt Ltd., 21^st Edition, 2005, v0l 2, 1369.

5. International Conference on Harmonization of Technical Requirements for the Registration of Pharmaceuticals for Human use. 1996. Validation of Analytical procedures: Methodology. ICHQ2B, Geneva, (CPMP/ICH/281/95).

6. Vogel’s Textbook of Quantitative Chemical Analysis, 5^th edition, ELBS Longman, London, 1997, 661-672.

7. Miller JC, Miller JN. In: Statistics for Analytical Chemistry, 2nd ed, Wiley, New York, 1984: 83–117.

Received on 10.04.2016 Modified on 21.05.2016

Research J. Pharm. and Tech. 2016; 9(7): 761-763.

DOI: 10.5958/0974-360X.2016.00144.X