The identification of carvedilol was done by FTIR spectroscopy. The UV spectrum was recorded in range 200-400 nm.
Melting point – It was determined in Thiele’s tube using capillary.
The solubility of carvedilol was determined in pH 7.4 phosphate buffer and in pH 7.4 phosphate
Determination of partition coefficient 83:
The partition coefficient of the drugs
was determined using n-octanol as the oil phase and phosphate buffer saline pH
7.4 as the aqueous phase. The n-octanol: phosphate buffer partition coefficient
serves as a parameter lipophilicity.an accurately weighed quantity of each
100mg drug was dissolved in 10 ml of the n-octanol phase and shaken at 370C
for 24 h against 10 ml buffer in a sealed container. The two phases were
separated and then they were analyzed spectro-photometerically
(ShimadzuUV-1800, Japan) for respective drug contents. The partition
coefficient of drug (Ko/w) was calculated using following
Estimation of Carvedilol
Determination of ?max for
To determine the ?max for carvedilol,
the standard solution of carvedilol was prepared in phosphate buffer saline pH 7.4
and scanned in the UV region by using UV spectrophotometer. The ?max
was determined for preparation of the standard curve of carvedilol.
preparation of standard curve of carvedilol
in phosphate buffers saline pH 7.4 .
Carvedilol was dissolve in 10 ml
methanol and volume is made up to 100 ml in volumetric flask with phosphate
buffer saline pH 7.4.1 ml of stock solution (100 mg/ml) was further diluted to get
solutions having concentrations 2mg/ml to 24 mg/ml.
Absorbance of each solution was measured at 285 nm using Shimadzu UV
Spectrophotometer and phosphate buffer pH 7.4 as a reference standard. The standard
curve was generated for entire range from 2 to 24 mg/ml.
FTIR absorption spectra of
carvedilol, polymers (HPMCK15M, PVPK30, and EC) and
physical mixture of carvedilol and polymers was recorded by using FTIR spectrophotometer
(Bruker FTIR ).