HPLC METHOD FOR DETERMINATION OF …

1 , (2011), 744-752 ISSN: 0974-1496 CODEN: RJCABP lacosamide S(-)ENANTIOMER V. K. Chakravarthy and D. G. Shankar HPLC METHOD FOR DETERMINATION OF lacosamide S(-)ENANTIOMER IN BULK AND PHARMACEUTICAL FORMULATION V. Kalyan Chakravarthy* and D. Gowri Shankar College of Pharmaceutical Sciences, Andhra University, Visakhapatnam-530 003, India. *E-mail: Kalyan224@rediffmail ABSTRACT A High performance liquid chromatography (HPLC) METHOD has been developed and subsequently validated for the DETERMINATION of lacosamide S (-) Enantiomer in bulk and pharmaceutical formulation.

2 Seperation was achieved in Isocratic mode with a Regis Pack ((Make: Regis Technologies (USA) ; 250 mm x mm ; particle size 5 m)) column with mobile phase containing 100% Ethanol as eluent at flow rate and the column temperature was 25 C. UV detection was performed at 210nm. The injection volume is 10 L. The METHOD is simple, rapid, and selective. The described METHOD of lacosamide S (-) Enantiomer is linear over a range of mcg/mL to mcg/mL. The METHOD precision for the DETERMINATION of lacosamide S (-) Enantiomer was below Limit of Detection (LOD) and Limit of Quantification (LOQ) of lacosamide S (-) Enantiomer was established and ranged from for LOD and for LOQ.

3 The METHOD is useful in the quality control of Bulk manufacturing and also in pharmaceutical formulations. Key Words: LC DETERMINATION , lacosamide , lacosamide S (-) Enantiomer. 2011 RAS YAN. All rights reserved. INTRODUCTION lacosamide tablets are indicated as adjunctive therapy in the treatment of partial-onset seizures in patients with epilepsy aged 17 years and older1-2. The chemical name of lacosamide (the single (R)-enantiomer), is (R)-2-acetamido-N-benzyl-3methoxypropion amide (Fig-1). lacosamide is a functionalized amino acid.

4 Its molecular formula is C13H18N2O3 and its molecular weight is lacosamide is a white to light yellow powder. It is sparingly soluble in water and slightly soluble in Acetonitrile and Ethanol. It is not official in any pharmacopoeia, few liquid chromatography procedures have been reported for the DETERMINATION of lacosamide in Bulk and Pharmaceutical dosage forms3-4. However there are no publications concerning the analysis of lacosamide S (-) Enantiomer (Fig-2) in bulk and Pharmaceutical dosage forms. The chemical name of lacosamide S (-) Enantiomer, is ( (2S)-2-acetamido-N-benzyl-3-methoxypropa namide).

5 The author has developed a liquid chromatographic METHOD which would serve as a rapid and reliable METHOD for the DETERMINATION of lacosamide S (-) Enantiomer [Fig 2] in Bulk and pharmaceutical dosage forms. In the proposed METHOD lacosamide and lacosamide S (-) Enantiomer were well separated and eluted before 30minutes. Finally the METHOD was thoroughly validated for lacosamide S (-) Enantiomer. EXPERIMENTAL Instrumentation5-7 The analysis of the drug was carried out on a waters LC system equipped with 2695pump, 2996 photodiode array detector was used and a Chiral stationary phase Regis Pack ((Make: Regis Technologies (USA) ; 250 mm x mm ; particle size 5 m)) was used.

6 The output of signal was monitored and integrated using waters Empower 2 software. Chemicals and solvents HPLC Grade water (Millipore), 100% Ethanol (HPLC Grade). , (2011), 744-752 lacosamide S(-)Enantiomer V. K. Chakravarthy and D. G. Shankar 745 Solutions: Mobile phase preparation:Use 100% Ethanol. Filter through m membrane filter and degas. Diluent preparation: Use Ethanol as diluent. Preparation of lacosamide S (-) Enantiomer stock solution preparation Accurately weigh and transfer about of lacosamide S (-) Enantiomer working standard into a 50 mL volumetric flask, add 30 mL of diluent and sonicate to dissolve.

7 Cool the solution to room temperature and dilute to volume with diluent. Resolution Solution preparation Accurately weigh and transfer about of lacosamide working standard into a 100 mL volumetric flask, add about 60 mL of diluent and sonicate to dissolve. Add mL of lacosamide S (-) Enantiomer stock solution and Mix. Dilute to volume with diluent. Placebo preparation Accurately weigh and transfer about placebo powder equivalent to 100 mg of lacosamide into a 200 mL volumetric flask add about 160 mL of diluent, sonicate for 15minutes with occasional shaking. Cool the solution to room temperature and dilute to volume with diluent and mix.

8 Centrifuge the solution at 3000 RPM for 5 minutes. Standard preparation Accurately weigh and transfer about of lacosamide working standard into a 200 mL volumetric flask, add 100 mL of diluent and sonicate to dissolve and dilute to volume with diluent. Transfer mL of above solution into a 250 mL volumetric flask and dilute to volume with diluent. Sample preparation Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to 100 mg of lacosamide into a 200 mL volumetric flask add about 120 mL of diluent, sonicate for 15minutes with occasional shaking.

9 Cool the solution to room temperature and dilute to volume with diluent and mix. Centrifuge the solution at 3000 RPM for 5 minutes. Note: Spike the S (-) Enantiomer stock solution at respective specification levels. Chromatographic conditions A Regis Pack ((Make: Regis Technologies (USA); 250 mm x mm ; particle size 5 m)) column was used for analysis at column temperature 25 C. The mobile phase was pumped through the column at a flow rate of The sample injection volume was 10 L. The photodiode array detector was set to a wavelength of UV-210nm for lacosamide and its S (-) Enantiomer and Chromatographic runtime was 30minutes.

10 Note: For Needle wash use filtered and degassed Ethanol. RESULTS AND DISCUSSION METHOD development To develop a suitable and robust LC method5-6 for the DETERMINATION of lacosamide S (-) Enantiomer, different mobile phases and columns were employed to achieve the best separation and resolution. The METHOD development was started with Chiralpak-IA ((Make: Diacel Columns (Japan); 250 mm ; particle size 5 m)) which gives best resolution between lacosamide and its S (-) Enantiomer. Separation was achieved with mobile phase cointaining Ethanol as eluent with flow rate of mL /min.