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Spectrophotometric Method for Determination of
Glucosamine in Tablets
PRIYA GAONKAR, VINEETA KHANVILKAR, RAJANI SHETTIGAR AND CHHAYA GADGOLI* Saraswathi Vidya Bhavan’s College of Pharmacy, Sonarpada, Dombivli (East)-421 201, India.
A rapid and sensitive method has been developed for the determination of glucosamine sulphate from tablets by UV-spectrophotometery. In this method, glucosamine sulphate was reacted with phenylisothiocyanate in presence of a base to yield phenylthiourea derivative. This derivative showed maximum absorbance at 240 nm. Beer’s law is obeyed in the concentration range of 5-25 µg/ml. The method was validated in terms of linearity, precision (relative standard deviation 1.1%), accuracy and specificity. The proposed method is the only method available for spectrophotometric determination of the drug. It is simple, precise, accurate, sensitive and reproducible and can be used for the routine quality control testing of the marketed formulations.
Glucosamine sulphate (GLS) is a water-soluble amine
sugar that is extensively used in the treatment of various
conditions of arthritis and collagen deficiency 1-4.
Literature survey reveals that the drug can be estimated
only by HPLC5 and no spectrophotometric methods have
been reported. The present study describes a simple,
sensitive, accurate and precise spectrophotometric method
for estimation of GLS in tablet formulation.
The reference standard of GLS was procured as a gift
sample from M/s Meyer Organics Ltd., Thane.
Phenylisothiocyanate (PITC) AR grade was purchased
from Fluka, Switzerland. All the other chemicals and
solvents used were of AR grade. UV SL-159 Elico make
spectrophotometer was used for the studies.
A standard solution of GLS (1000 µg/ml) was prepared in
0.1 M aqueous sodium acetate solution. (S1). Ten tablets
(Cartilamine® 500 mg, Troikaa, Ahmedabad; and Cartisafe
Forte® 500 mg Jenburkt, Mumbai) were weighed and
finely powdered. The powder equivalent to GLS (100
mg) was dissolved in 50 ml of 0.1 M aqueous sodium
acetate solution. The solution was then filtered and the
residue was washed thoroughly with 0.1 M aqueous
sodium acetate solution. The filtrate and the washings
were combined in a 100 ml volumetric flask and diluted to
the mark with 0.1 M aqueous sodium acetate solution (T1).
January - February 2006
The solution of GLS should be prepared 24 h before the
For the preparation of phenylthiourea (PTH) derivative,
an aliquot of 4 ml of the standard solution of GLS (S1)
was transferred to a 25 ml volumetric flask and 0.4 ml
PITC along with 15 ml methanol was added. The volume
was made up to the mark with 60% aqueous methanol
(S2). An aliquot of 10 ml of S2 was transferred to a
calibrated test tube and was heated for 20 min. in a boiling water bath. The test tube was cooled and the volume was
made to 10 ml with distilled water. The solution was made
free of unreacted PITC by extraction with diethyl ether
(two portions of 15 ml each) and the aqueous layer
containing PTH derivative of GLS was collected. An
aliquot of 5 ml of this aqueous layer was transferred to a
50 ml volumetric flask and the volume was made up to
the mark with distilled water (S3). The sample solution T1
was treated in the same manner as that of the standard to
For the calibration curve, a series of dilutions of S3 were
prepared in distilled water so as to obtain the
concentrations in the range of 5-25 µg/ml. The
absorbance was measured on UV/Vis spectrophotometer
at 240 nm against reagent blank. For quantification of
GLS in the tablet formulations, an aliquot of 2 ml of T3
was diluted to 10 ml with distilled water and the
absorbance was measured at 240 nm on UV/Vis
spectrophotometer. The concentration of GLS...
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Lohmander, L.S. and Felson, D.T., J. Rheumatol., 1997, 24,782.
Liang, M.H., Pillemer, S.R., Steen, V.D. and Wolfe, F., Arthritis
Rheum., 1998, 41, 778.
Foley, C.M. and Kratz, A.M., J. Amer. Nutraceutical Assn.,
1999, 2, 6.
Indian J. Pharm. Sci., 2006, 68 (1): 83-84
January - February 2006
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