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Indian Journal of Chemical Technology (IJCT) >
IJCT Vol.12 [2005] >
IJCT Vol.12(5) [September 2005] >
| Title: | Four rapid and sensitive methods for the assay of amoxycillin in pharmaceuticals using bromate-bromide mixture and two dyes |
| Authors: | Ramakrishna, V
Basavaiah, K |
| Keywords: | Amoxycillin determination
titrimetry
spectrophotometry
bromate-bromide
dyes |
| Issue Date: | Sep-2005 |
| Publisher: | CSIR |
| IPC Code: | A61K9/00 |
| Abstract: | Four new methods using titrimetry and
spectrophotometry are described for the rapid determination of amoxycillin in
bulk drug and dosage forms. In direct titrimetry (Method A), the drug is
titrated with bromate–bromide mixture in acid medium using methyl orange
indicator. Back titrimetry (Method B) entails adding a known excess amount of
bromate-bromide mixture to the drug solution in acid medium, followed by
determination of residual bromine iodometrically. Both spectrophotometric
methods are based on the oxidation–bromination of amoxyciillin by in situ generated bromine followed by
estimation of unreacted bromine with methyl orange (Method C) or indigo carmine
(Method D) and measuring the change in absorbance at 520 or 610 nm. In all the
methods, qunatitation is based on the amount of bromate that has reacted with
amoxycillin. The experimental conditions have been optimized. Calculations are
based on 1:1 and 1:2 (amoxycillin: bromate) stoichiometry for method A and
Method B, respectively. Method A is applicable over 2-16 mg range, and 1-9 mg
of amoxycillin could be determined by method B. In spectrophotometric methods,
the absorbance is found to increase linearly with increasing concentration of
amoxycillin which is corroborated by the calculated correlation coefficient (r) of 0.9964 (Method C) and 0.9959
(Method D). The calibration graphs are found to be linear over 0.1–1.2 and 0.5 –
4.0  g mL-1 for method C and
method D, respectively. Method C with a molar absorptivity of 1.60  105 L mol-1 cm-1 is found to be
more sensitive than method D (ε = 5.83 104 L mol-1 cm-1). The limits of
detection and quantification for both spectrophotometric methods are reported.
Statistical evaluation of the methods was examined by determining intra-day and
inter-day precisions. The methods were applied to the determination of
amoxycillin pharmaceutical formulations. No interference was observed from
excipients and the validity of the methods was tested against a reference
method. |
| Page(s): | 543-549 |
| ISSN: | 0975-0991 (Online); 0971-457X (Print) |
| Source: | IJCT Vol.12(5) [September 2005]
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