Determination of amoxycillin in pharmaceutical forms by visible spectrophotometry and HPLC

Abstract

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="metricconverter"> Two rapid assay procedures based on visible spectrophotometry and high performance liquid chromatography (HPLC) have been developed for amoxycillin (AMX) in bulk drug and in dosage forms. Spectrophotometric method is based on the formation of a charge-transfer (CT) complex between chloranilic acid (CAA) as a <img src='/image/spc_char/pi.gif'>-acceptor and amoxycillin (AMX) as an n-donor in acetonitrile solvent, the absorbance of the complex being measured at 520 nm. Beer’s law is obeyed for 10-200 <img src='/image/spc_char/micro.gif'>g mL^-1 with an apparent molar absorptivity of 1.3 <img src='/image/spc_char/cross.gif'> 10³ L mol^-1 cm^-1 and a Sandell sensitivity of 0.2741 <img src='/image/spc_char/micro.gif'>g cm^-2. The HPLC determination was performed on a reversed phase column (Hypersil C₁₈ 5 µm; 250<img src='/image/spc_char/cross.gif'>4.6 mm i.d) using a mobile phase (1 mL min^-1) consisting of acetonitrile-0.1% ortho phosphoric acid (<i>p</i>H 3.0)-60:40 (<i>v</i>/<i>v</i>) with UV-detection at 230 nm. A rectilinear relationship between mean peak area and concentration of AMX was observed in the range 7.2-396 <img src='/image/spc_char/micro.gif'>g mL^-1 with a detection limit of 1.5 <img src='/image/spc_char/micro.gif'>g mL^-1 and a quantitation limit of 4.5 <img src='/image/spc_char/micro.gif'>g mL^-1. Intra-day and inter-day precision, and accuracy of the methods have been established according to the current ICH guidelines. The methods have been successfully applied to the assay of AMX in preparations and the results were statistically compared with those of the reference method by applying Student’s t-test and F-test. </smarttagtype>