Studies on UV Spectrophotometric Analysis of Drugs Terbinafine Hydrochloride and Clarithromycin

Quality assurance for control of pharmaceutical chemicals and formulations is essential for ensuring
the availability of safe and effective drug formulations to consumers. Quantitative estimation of the
chemical entity of a drug is vital for maintaining and assuring the quality. Several distinct problems are
encountered in the quantitative estimation of the drug in bulk samples and formulations. The
interferences caused by a number of sources such as the degradation products of the drugs when
they are stored for a long time, the presence of other drugs in combination products and the various
additives incorporated in formulations have to be kept in view during the course of assay development
for drugs in formulations. Among the various techniques for the development of assay methods, uvvisible
spectrophotometry combines the advantages of low cost, easy maintenance and simplicity with
the possibility of achieving high sensitivity and selectivity with good precision, accuracy and reliability.
The selectivity and sensitivity of the uv-visible spectrophotometric method depends only on the nature
of chemical reactions involved in color development and not on the sophistication of the equipment.
The expenditure incurred on the assay determination in visible spectrophotometric methods depends
on selecting the reagents (low cost, readily available) for the color development.
With above facts I am herewith enclosing my research work in estimation of terbinafine hydrochloride
and clarithromycin with the help of UV spectrophotometric method as narrated below.
One simple and sensitive procedure (UV spectophotometric method) for the assay of two drugs
namely terbinafine hydrochloride and clarithromycin in pure form and formulations. This method
involves the formation of ion-association complex between TRB or CAM and the picric acid. In order
to establish the optimum conditions necessary for rapid and quantitative formation of coloured product
with maximum stability and sensitivity, the author performed experiments by measuring the
absorbance at λmax 350nm of a series of solutions, varying one and fixing the other parameters in
each case such as type, volume and concentration of acid, organic solvent used for extraction, ratio of
organic phase to aqueous phase during extraction, shaking time and temperature. The variable
parameters were optimized. The results were statistically validated. The regression analysis using the
method of least squares was made for the slope (b), standard deviation (Sb), intercept (a), standard
deviation on intercept (Sa), standard error of estimation (Se) and correlation coefficient (r) obtained
from different concentrations. The data obtained in the determination of each drug with different
reagents are summarized in this section. The selectivity (or specificity) of each proposed method was
ascertained through interference studies with other active and inactive ingredients usually present in
pharmaceutical preparations.