Acta Pharm. 58 (2008) 111-117
Short communication
Use of Folin-Ciocalteu phenol reagent and
3-methyl-2-benzothiazolinone hydrazine hydrochloride in the determination of
oxcarbazepine in pharmaceuticals
MURUGANATHAN
GANDHIMATHI and THENGUNGAL KOCHUPAPPY
gands@yahoo.co.in
Department of
Pharmaceutical Analysis, College of
Pharmacy, Sri Ramakrishna Institute of Paramedical Sciences, Coimbatore-641
044,
Accepted February 12, 2008
Two spectrophotometric methods are proposed for the assay of oxcarbazepine
(OXC) in bulk and dosage forms using Folin-Ciocalteu phenol reagent (FCP) and
3-methyl-2-benzothiazolinone hydrazine hydrochloride (MBTH) as reagents. The
first method involves addition of FCP reagent to OXC in alkaline medium
followed by measurement of absorbance at 760 nm (method A), and the other involves
addition of a fixed volume of MBTH after treatment of OXC with ferric chloride
and measurement of absorbance at 456 nm (method B). In both methods, the amount
of chromogen formed corresponds to the amount of OXC and the measured
absorbance was found to increase linearly with the concentration of OXC, which
is corroborated by the correlation coefficients of 0.9985 and 0.9984 for method
A and B, respectively. The systems obey Beer’s law for 5-30 µg mL-1 and 10-50 µg mL-1 for methods A and B, respectively.
The apparent molar absorptivity was calculated to be 8.06 × 103 L
mol-1 cm-1 and 3.126 × 103 L mol-1 cm-1 for methods A and B, respectively.
The limits of detection (LOD) and
limit of quantification (LOQ) were
calculated to be 1.6 and 5 µg mL-1 for method A and 3 and 10 µg mL-1 for method B. The inter-day and
intra-day imprecision of the methods were found to be in the range of 1.1-1.7 and 0.9-1.1 % for
method A, and 1.1-1.9 and 0.6-0.9 % for method B. The accuracy ranged between 98.9-99.7 % and 99.3-100.1 for
method A and B, respectively. No interference was observed from common
pharmaceutical excipients. The methods were successfully applied to the assay
of OXC in tablet preparations.
Keywords: oxcarbazepine, spectrophotometry,
Folin-Ciocalteu reagent, 3-methyl-2-benzothiazolinone hydrazine hydrochloride,
pharmaceuticals, validation