Author(s): Suchita Kelgaonkar*, R. S. Moon, T. M. Kalyankar
Two sensitive, precise, accurate, simple, and economical methods were developed and validated for simultaneous estimation of
Theophylline and Terbutaline sulphate in Synthetic mixture form. Method A is simultaneous equation method, wherein the
wavelengths selected for Theophylline is 274.8 nm and for Terbutaline sulphate is 295.6 nm. Whereas Method B is absorption ratio
method wherein the wavelength selected for isosbestic point is 287.3 nm and 274.8 nm maximum absorption of Theophylline. In
both methods, Theophylline and Terbutaline sulphate followed the linearity concentration range 4-24 mcg/ml for Theophylline and
2-12 mcg/ml for Terbutaline sulphate by these methods. Standard calibration curve for both Theophylline and Terbutaline sulphate
with correlation coefficient (r2) value is 0.998 for Theophylline and 0.997 for Terbutaline sulphate for method A whereas 0.998 for
Theophylline and 0.997 for TES for method B. The proposed methods were validated according to ICH guidelines in terms of
linearity, accuracy, precision, LOD and LOQ. Percentage assay was found to be in the range 100.20 – 100.75 for method A and
100.13-100.73 for method B. In precision % RSD was found to be 0.705 & 0.364 for Theophylline and 0.899 & 1.238 for
Terbutaline sulphate for method A and 1.295 & 0.440 for Theophylline for method B and 0.548 & 2.433 for Terbutaline sulphate for
method B. The mean percent recoveries was found to be in range 99.82-101.17% for method A and 100.14 – 100.96 for method B.
LOD and LOQ values found to be 0.0496 & 0.150 for Theophylline and 0.442 & 1.342 for Terbutaline sulphate for method A and
0.0524 and 0.158 for Theophylline & 0.150 & 1.342 for Terbutaline sulphate for method B. Degradation conditions were carried
under conditions of photolytic, sunlight and thermal degradation.