are carried out at 25 0 C
in methanol and in water, very slightly soluble in phosphate buffer.
Freely soluble in water,
soluble in acetonitrile,spraingly soluble in methanol.
8.2. Determination Of Working Wavelength (?max)
In simultaneous estimation of two drugs isobestic wavelength is used.
Isobestic point is the wavelength where the molar absorptivity is the same for
two substances that are interconvertible. So this wavelength is used in
simultaneous estimation to estimate both drugs accurately.
Preparation of standard stock solution of METFORMIN
10 mg of METFORMINwas
weighed and transferred in to 100ml volumetric flask and dissolved in methanol
and then make up to the mark with methanol and prepare 10 µg /ml of solution by
diluting 1ml to 10ml with methanol.
Preparation of standard stock solution of EMPAGLIFLOZIN
10mg of EMPAGLIFLOZINwas weighed in to 100ml
volumetric flask and dissolved in Methanol and then dilute up to the mark with
methanol and prepare 10 µg /ml of solution by diluting 1ml to 10ml with
The wavelength of maximum absorption
(?max) of the drug, 10 ?g/ml solution of the drugs in methanol were
scanned using UV-Visible spectrophotometer within the wavelength region of
200–400 nm against methanol as blank. The resulting spectra are shown in the
fig. no. 8.1, 8.2 and 8.3 and the absorption curve shows characteristic
absorption maxima at 240 nm for METFORMIN, 229 nm for EMPAGLIFLOZIN and
255nm for the combination.
UV-VIS spectrum of METFORMIN
?max was found to be 240 nm
in the figure 8.1
Fig. 8.2: UV-VIS spectrum
?max was found to be 229nm for EMPAGLIFLOZINshown
in the figure 8.2
Fig. 8.3: UV-VIS spectrum of METFORMIN and EMPAGLIFLOZIN and the isosbestic
point was 255nm
The Isobestic point was found to be 255nm for METFORMINand EMPAGLIFLOZIN in combination and was
shown in figure 8.3