Validated Spectroscopic Method for Estimation of Tramadol Hydrochloride from Tablet Formulation

 

Deepali Gharge*, Kundan Pawar, Pallavi Salve and Pandurang Dhabale

Government College of Pharmacy, Karad, Dist –Satara-415124, M.S., India.

*Corresponding Author E-mail: deepali_gharge@rediffmail.com

 

ABSTRACT:

Tramadol hydrochloride is a centrally acting analgesic, used for treating moderate to severe pain. Various methods for analysis of the same are available but are time consuming and expensive. Here we have developed a new, precise and simple UV spectrophotometric method for estimation of tramadol hydrochloride from tablet formulation. The drug obeyed the Beer’s law and showed good correlation. Absorption maxima of tramadol hydrochloride in methanol diluted with distilled water was found to be at 270.5nm. Beer’s law was obeyed in concentration range 0 – 20 mcg/ml. The results of analysis were validated by recovery studies. The recovery was more than 99%. The method was found to be simple, accurate, precise, economical and robust.

 

KEYWORDS: Tramadol hydrochloride, UV spectrophotometry, Recovery study.

 

 


 

INTRODUCTION:

Tramadol hydrochloride is a centrally acting analgesic, used for treating moderate to severe pain. Tramadol hydrochloride possesses agonist actions at the μ-opioid receptor and effects reuptake at the noradrenergic and serotonergic systems. Tramadol is a compound with μ-agonist activity. Chemically it is [2-(dimethylaminomethyl)-1-(3-methoxyphenyl) cyclohexanol]. It is used to treat moderate to moderately severe pain and most types of neuralgia, including trigeminal neuralgia. Tramadol is available in the form of oral drops, tablets, capsules and injections1.  There are various methods available for estimation of tramadol hydrochloride like UV spectrophotometric2,3, spectrofluorometry4, HPLC5 , gas chromatography6, GC-MS and LC-MS7, capillary electrophoresis8, HPTLC9, HPTLC-densitometry10,11, etc. However some of these methods are costlier and time consuming. To overcome these difficulties spectrophotometric analysis serves to be the quickest, promising and reliable method for routine analytical needs. The aim of the present study is to develop a new simple, rapid, reliable and precise UV spectrophotometric method for analysis of tramadol from tablet formulation; method is based on measurement of UV absorbance of tramadol hydrochloride in methanol diluted with distilled water.

 

MATERIALS AND METHODS:

Apparatus:

Spectral runs were made on a Shimadzu UV-Visible spectrophotometer, model- 1700 (Japan) was employed with spectral bandwidth of 1 nm and wavelength accuracy of ± 0.3 nm with automatic wavelength corrections with a pair of 10 mm quartz cells. Glasswares used in each procedure were soaked overnight in a mixture of chromic acid and sulphuric acid rinsed thoroughly with double distilled water and dried in hot air oven.

 

Reagents and Solution:

All the reagents used in this assay were of analytical grade and the reagent solutions were prepared using preanalysed distilled water. Tramadol pure drug was obtained as a gift sample from Aristo Pharmaceuticals Limited, Mumbai. Tablets of tramadol hydrochloride were purchased from local market for analysis. Methanol diluted with distilled water was used as a solvent for the spectrophotometric estimation.

 

EXPERIMENTAL:

Determination of λmax:

Weighed an accurate amount 100mg of tramadol hydrochloride was dissolved in 20ml methanol and diluted upto 100ml by double distilled water to obtain a 1000mcg/ml concentration of tramadol hydrochloride in solution. This solution was subjected to scanning between 200 – 400 nm and absorption maxima at 270.5 nm was determined.

 

Standard Stock Solution:

A stock solution containing 1000mcg/ml of pure drug was prepared by dissolving accurately weighed 100mg of tramadol in 20ml methanol volume made upto 100ml mark by distilled water to produce 100ml solution in a volumetric flask.

Fig. 1: UV Scan of Tramadol in methanol diluted with distilled water

 

Table No. I: Optical characteristics and precision

Absorption maxima

270.5 nm

Beer's law limit

0 – 20 mcg/ml

Coefficient of Correlation

0.999879

Regression equation

Y = 0.00599 X + 0.005

Slope

0.00599

y intercept

0.005

Molar absorptivity (lit/mole/cm)

1796.041431

Sandell's sensitivity (mcg/Sq.cm/0.001)

0.166945

% COV

1.098899

Confidence limit with 0.05 level

0.009937

 

Working standard solution:

10 ml of the stock solution was further diluted to 100ml with methanol diluted with distilled water to obtain a working standard solution containing 100mcg/mL.

 

Linearity and Calibration:

The aliquots working standard solution was diluted serially with sufficient methanol diluted with distilled water to obtain the concentration range of 20 – 100 mcg/ml. A calibration curve for tramadol was obtained by measuring the absorbance at the λmax of 270.5 nm. Statistical parameters like the slope, intercept, coefficient of correlation, standard deviation, relative standard deviation, and standard error were determined.

 

Analysis of Marketed Tablet Formulation:

Accurately weighed the 20 tablets and powdered. The powder equivalent to 50mg of tramadol was transferred to 50ml volumetric flask and 10ml methanol is added to dissolve the tramadol in it and made the volume to mark with distilled water to produce 1000mcg/ml of tramadol hydrochloride solution. This mixture was sonicated for 15 minutes and filtered through Whatman filter paper No. 41. To produce stock solution containing 100mcg/ml of tramadol hydrochloride 10ml of above solution diluted to 100ml with methanol diluted with distilled water. Aliquots (1ml, 2ml, 3ml, 4ml, 5ml and 6ml) of the sample were removed and diluted to 10 ml with methanol diluted with distilled water to obtain strengths as 10mcg/ml, 20mcg/ml, 30mcg/ml, 40mcg/ml, 50mcg/ml and 60mcg/ml. The respective absorbances are determined at 270.5nm against the methanol diluted with distilled water as blank. Two different formulations of different manufacturers were used for study.

 

Fig. 2: Calibration curve of tramadol in methanol diluted with distilled water

 

Recovery studies:

Recovery studies were performed to judge the accuracy of the method. 1ml of standard formulation (100mcg/ml) was taken in three 10ml volumetric flask and to it 80%, 100% and 120% (i.e. 0.8ml, 1.0ml, 1.2ml) of working standard solution (100mcg/ml) added respectively and made the volume upto the mark. The respective absorbance at 270.5nm was recorded against the blank. The amount of added concentration was determined from the obtained absorbance values and percent recovery was determined for each formulation.12

 

Robustness:

The evaluation of robustness was performed for system suitability to ensure the validity of analytical procedure. This was done by varying the instrument, analyst, and time of study. The analysis was performed on Shimadzu UV-Visible spectrophotometer, model- 1700 (Japan) and UV-Visible Spectrophotometer model -1800 (Japan). Interday and intraday analysis was performed by changing the analyst.

 

RESULTS:

The UV scan of standard solution between 200 – 400 nm showed the absorption maxima at 270.5nm, shown in fig. 1. The Beer’s law was verified from the calibration curve by plotting a graph of concentration vs absorbance. The plot is shown in fig. 2. Regression analysis showed very good correlation. The calibration plot revealed zero intercept which is clear by the regression analysis equation Y = mX + C. (Where Y is absorbance, m is the slope and X is the concentration of tramadol hydrochloride in mcg/ml) as obtained by the least square method. The results thus obtained are depicted in Table No.I. The results of analysis for assay and recovery studies for two different formulations were studied and are shown in Table No. II and III. No significant variations were observed on intraday and interday analysis. Also no significant variations were observed on changing the instrument.

 

 


Table No. II

Formulation

Label Claim in mg

% Estimated

Amount found in mg

%  COV

Limit of detection (LOD)

Limit of quantitation (LOQ)

Tablet I

50

99.91%

49.95

0.23612

0.4674

1.4163

Tablet II

50

100.27%

50.13

0.20126

0.3979

1.2060

COV - Coefficient of variation

 

Table No. III – Recovery study data

Tablet

Percentage of working standard added

Concentration

% Estimated ± S.D.

% R.S.D.

Tablet I

80%

18

97.66±0.0021213

0.85536

 

100%

20

99.60±0.0025495

0.90729

 

120%

22

100.27±0.0035355

1.13681

Tablet II

80%

18

100.05±0.0021

0.63091

 

100%

20

100.85±0.0034

0.84507

 

120%

22

99.43±0.0031

0.77922

S.D.- Standard Deviation, R.S.D- Relative Standard Deviation

 

 


DISCUSSION:

The spectrum of tramadol hydrochloride in methanol diluted with distilled water showed the absorption maxima at 270.5 nm. No effect of dilution was observed on the maxima, which confirmed the maxima at 270.5nm. The statistical analysis of data obtained for the calibration curve of tramadol hydrochloride in pure solution indicated a high level of precision for the proposed method, as evidenced by low value of coefficient of variation. The coefficient of correlation was highly significant. The linearity range was observed between 0 – 20 mcg/ml. The plot clearly showed a straight line passing through origin (Y = 0.00599 X + 0.005). The estimated method was validated by low values of % RSD and standard error, indicating accuracy and precision of the methods. Excellent recovery studies further proves the accuracy of the method. Robustness of the method was studied by varying the instrument, time of study and analyst. Reproducibility of the results confirmed the robustness of the method.

 

CONCLUSIONS:

From the results and discussion the method described in this paper for the determination of tramadol hydrochloride from tablet formulation is simple, accurate, sensitive reproducible and economical. The proposed method utilizes inexpensive solvents. The proposed method could be applied for routine analysis in quality control laboratories.

 

ACKNOWLEDGEMENTS:

Authors are grateful to Aristo Pharmaceuticals Limited, Mumbai for providing the gift sample of tramadol hydrochloride. We are also thankful to the Principal and Head of Pharmaceutical Chemistry Department of Government College of Pharmacy, Karad for providing the necessary facilities to carry out this work.

 

REFERENCES:

1.        Anonymous. The Martindale Extra Pharmacopoeia. 1985, EP 31: 1742-1744.

2.        Abdellatef HE. Kinetic spectrophotometric determination of tramadol hydrochloride in pharmaceutical formulation. Journal of Pharmaceutical and Biomedical Analysis. 2002; 29: 835-842.

3.        Puranik Manisha, Hirudkar A, Wadher SJ, Yeole PG. Development and validation of spectrophotometric methods for simultaneous estimation of tramadol hydrochloride and chlorzoxazone in tablet dosage form. Indian Journal of Pharmaceutical Sciences. 2006: 737-739.

4.        Abdellatef HE, El-Henawee MM., El- Sayed HM, Ayad, MM. Spectrophotometric and spectrofluorimetric methods for analysis of tramadol, acebutolol and dothiepin in pharmaceutical preparations. Spectrochimica Acta A Molecular and Biomolecular Spectroscopy. 2006; 65(5):1087-1092

5.        Negro S, Salama A, Sánchez Y, Azuara ML, Barcia, E. Compatibility and stability of tramadol and dexamethasone in solution and its use in terminally ill patients. Journal of Clinical Pharmacology and Therapeutics. 2007; 32(5): 441-444.

6.        Tao Q, Stone, DJJr, Borenstein MR, Jean-Bart V, Codd EE, Coogan TP, Desai-Krieger D, Liao S, Raffa RB. Gas chromatographic method using 425 nitrogen-phosphorus detection for the measurement of tramadol and its Odesmethyl metabolite in plasma and brain tissue of mice and rats. Journal of Chromatography B: Biomedical Science Applications. 2001; 763: 165-171.

7.        Moore C, Marinetti L, Coulter C, Crompton, K. Analysis of pain management drugs, specifically fentanyl, in hair: Application to forensic specimens. Forensic Science International. 2008; 176(1): 47-50.

8.        Li J, Ju H. Simultaneous determination of ethamsylate, tramadol and lidocaine in human urine by capillary electrophoresis with electrochemiluminescence detection. Electrophoresis. 2006; 27(17): 3467-3474.

9.        Krzek J, Starek M. Quality assessment for tramadol in pharmaceutical preparations with thin layer chromatography and densitometry. Biomedical Chromatography. 2004; 18(8): 589-599.

10.     Ahrens B, Blankenhorn D, Spangenberg, B. Advanced fibre optical scanning in thin-layer chromatography for drug identification. Journal of Chromatography B Analytical Technology in Biomedical and Life Sciences. 2002; 772: 11-18.

11.     Venkateshwarlu K, Reddy YN, Srisailam K, Rajkumar V, Pai MG. Determination of tramadol in capsules by high performance thin layer chromatography – densitometry. Current Trends in Biotechnology and Pharmacy. 2008; 2 (3): 421 -425.

12.     International Conference on Harmonization, Guidance for Industry In; Q2B Validation of Analytical Procedures: Methodology. 1996: 2.

 

 

 

 

 

Received on 25.09.2009          Modified on 21.11.2009

Accepted on 20.12.2009         © RJPT All right reserved

Research J. Pharm. and Tech. 3(1): Jan.-Mar. 2010; Page 260-262