Development of First Order Derivative UV –Spectrophotometric Method for the Estimation of Sitagliptin Phosphate

 

Pallaw Ghodeswar*, Avnish Jain and Sanjay Jain

Smriti College of Pharmaceutical Education 4/1 Pipliya Kumar, Mayakhedi Road, Dewas Naka, Nipania, Indore (M.P.) – 452010, India.

*Corresponding Author E-mail: pallav_87@yahoo.co.in

ABSTRACT:

A simple, rapid, sensitive, economic and accurate first order derivative Spectrophotometric method has been developed for the estimation of Sitagliptin Phosphate in bulk and tablets. In distilled water λ_max of Sitagliptin Phosphate was found to be 267.4 nm.  The same spectra was derivatized using derivative mode into first order derivative at ∆N =5, the amplitude of peak was measured at 256.4 nm. In the method linearity was observed in the concentration range of 5-35 μg/ml. the assay results by the proposed method were in good agreement with label claim, the method was validated statistically and recovery studies.

 

 

 

 

INTRODUCTION:

Sitagliptin is an oral diabetes medicine that helps control blood sugar levels¹. Sitagliptin is a DPP-4 inhibitor, which is believed to exert its actions in patients with type 2 diabetes by slowing the inactivation of incretin hormones¹. Concentrations of the active intact hormones are increased by sitagliptin, thereby increasing and prolonging the action of these hormones. Incretin hormones, including glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are released by the intestine throughout the day, and levels are increased in response to a meal². When blood glucose concentrations are normal or elevated, GLP-1 and GIP increase insulin synthesis and release from pancreatic beta cells by intracellular signaling pathways involving cyclic AMP. GLP-1 also lowers glucagon secretion from pancreatic alpha cells, leading to reduced hepatic glucose production. Sitagliptin demonstrates selectivity for DPP-4 and does not inhibit DPP-8 or DPP-9 activity in vitro at concentrations approximating those from therapeutic doses³.

 

Spectroscopy is the study of the interaction between radiation (electromagnetic radiation, or light, as well as particle radiation) and matter⁴. Spectroscopy is often used in physical and analytical chemistry for the identification of substances through the spectrum emitted from or absorbed by them. UV spectroscopy is concern with the study of absorption of UV radiation which ranges from 200–400nm. Compounds which are colored absorb radiation from 400-800nm. But compound which are colorless absorb radiation in the UV radiation in both UV as well as visible spectroscopy only the valency electrons absorb the energy, thereby the molecule undergoes transition from ground state to excited state⁵. This absorption is characteristic and depends on the nature of electron present. The intensity of absorption depends on the concentration and path length as given by Beer- Lambert’s law⁶.

 

 

EXPERIMENTAL:

Chemical and reagents

A solvent or solvent mixture in which all the component of formulation are soluble, and stable is selected, another point that needs consideration in selecting the solvent to show maximum absorbance in the selected solvent. Double distilled water was used throughout the study .Sitagliptin phosphate drug sample was received as gift sample from MSD Pharmaceuticals PVT Limited, Bhiwandi, MH. All other chemicals used were of analytical reagent (AR) grade.

 

Estimation of First Order derivative at absorption maxima (λ_max )

Derivative spectroscopy uses first or higher derivatives of absorbance with respect to wavelength for qualitative analysis and for quantification. The concept of derivatizing spectral data has many advantages. The first-order derivative is the rate of change absorbance with respect to wavelength. A first-order derivative starts and finishes at zero. It also passes through zero at same wavelength as λ_max of the absorbance band⁶.

 

Figure no.1. Overlay of sitagliptinat267.2nm

 

Figure  no.2:- Calibration curve for Sitagliptin

 

Regression equation :- Y= 0.004x +0.016

 

Figure no.3.  UV Spectra of Sitagliptin at 100 µg/ml concentration

Twenty tablets were weighed and powdered. Powder equivalent to 128.5 mg Sitagliptin phosphate was transferred to a 100 ml volumetric flask and 25 ml distilled water was added and shaken for about 5 minutes to extract the drug. Then volume was made up to the mark with distilled water. It was filtered through Whatman filter paper # 41. Filtered extract was appropriately diluted with distilled water and absorbance and amplitude was noted at 267.2-nm against reagent blank and drug content was determined.

 

Fig. no. 4 Derivative spectra of Sitagliptin drugs at 100 µg/ml Conc.

 

Figure no.5.  first order Derivative curve of sitagliptin

Regression equation: - y = 0.0002x + 0.0004s

R²= 0.997

 

 

Table :1 Total Data of Analysis of Tablet Formulation, Statistical Validation and Recovery  studies

Formulations	λ(nm)	Label claim mg/tab	Amount found* mg/tab	Label claim (%)	S.D.*	% COV	S.E*.	Amount Added (%)	%  Recovery #
JANUVIA	at 267.2nm	100	103	103	1.015	0.98	0.5858	40	97.83
	At  256nm	100	96.16	96.15	0.7638	0.45	0.441	40	97.91

 

 

Preparation of standard calibration curve and method validation

This stock solution (1000 µg/ml) was further diluted with distilled water to obtain various dilutions containing 20, 40, 60, 80, 100, 120 and 140 µg/ml of drug. All dilutions were derivatized into the first order derivative (n=5), the amplitudes of corresponding troughs were measured at 267.2-nm against reagent blanks to get calibration curve (Overlay) (Fig 1) and Drug follows linearity in the concentration range of 20-140µg/ml. as shown in the Calibration curve of Sitagliptin phosphate (Fig. 2). Further, the graph at 100nm shown the uv-spectra at 267.2nm and derivative spectra at 256.0 nm (Fig. 3 and 4) respectively and followed with first order derivative of sitagliptin phosphate⁸ (Fig. 5).

 

RECOVERY STUDIES

To study the accuracy, reproducibility and the precision of the proposed method, recovery experiments were carried out. For recovery study, 100 mg of Sitagliptin phosphate (pure drug) was added to preanalyzed tablet powder equivalent to 100 mg of Sitagliptin phosphate. Procedure of analysis was same. The percent recoveries were calculated and reported in Table 1.

 

RESULTS AND DISCUSSION:

Table 1 showed the mean percent label claim was 102.06% and Table 2 provides the optical characteristics data of Sitagliptin phosphates. Since percent label claims are very close to 100% and values of standard deviation and percent coefficient of variation are significantly low, therefore these indicate the accuracy of the proposed method.

 

 

Table 2:  Optical Characteristics data of Sitagliptin phosphate

Parameters	Values
Working λ (nm)	267.2-nm	256nm
Beer’s law limit (µg/ml)	20-140	20-140
Correlation coefficient*	0.996	0.997
Intercept*	0.016	0.0004
Slope*	0.004	0.0002

*Mean of 6 values (n=6)

 

Percent recoveries estimated in recovery studies were also very close to 100 indicating the accuracy of the proposed method. Values of standard deviation and percent coefficient of variation in case of recovery studies (Table 1) are satisfactorily low and confirmed the accuracy of the proposed method. 

 

REFERENCES:

1.    U.S. Food and Drug Administration (October 17, 2006). "FDA Approves New Treatment for Diabetes.

2.    Gorvel JP, Ferrero A, Chambraud L, Rigal A, Bonicel J, Maroux S: Expression of sucrase-isomaltase and dipeptidylpeptidase IV in human small intestine and colon. Gastroenterology. 101:618-625 (1991).

3.    Herman G, Stevens C, Van Dyck K, Bergman A, Yi B, De Smet M, Snyder K, Hilliard D, Tanen M, Tanaka W, Wang A, Zeng W, Musson D, Winchell G, Davies M, Ramael S, Gottesdiener K, Wagner J. "Pharmacokinetics and pharmacodynamics of sitagliptin, an inhibitor of dipeptidyl peptidase IV, in healthy subjects: results from two randomized, double-blind, placebo-controlled studies with single oral doses.” Clin Pharmacol Ther 78, 675–88 (2005).

4.    Rendina, George. Experimental Methods in Modern Biochemistry W. B. Saunders      Company: Philadelphia, PA. 1976. pp. 46-55 73.

5.    Dyer, J. R. Applications of Absorption Spectroscopy of Organic Compounds. Prentice-  Hall, Inc. 1965

6.    Skoog, Principles of Instrumental Analysis. 6th ed. Thomson Brooks/Cole. 2007, 169-173.

7.    Januvia Side Effects and Drug Interactions". RxList.com. 2007. Retrieved 2007, 11-28.

8.    Beckette, A.H. Stenlake, J.B., practical pharmaceutical chemistry, CBC publication 4th edition, 1988, Vol ΙΙ, pg no 284-296.

 

 

Received on 22.11.2010        Modified on 09.12.2010

Accepted on 20.12.2010      © RJPT All right reserved