Dissolution condition:
Medium : 900 ml, 0.01M Hydrochloric acid.
Apparatus : Paddle
Speed : 100 RPM
Time : 45 minutes
Temperature : 37°C (± 0.5°C)
Preparation
of 0.01M Hydrochloric acid:
Dilute 0.86ml of conc. Hydrochloric
acid in 1000ml volumetric flask with water.
Method:
Introduce the dissolution medium,
free from dissolved air in to the vessel of the apparatus. Warm the dissolution
medium to between 36.5°C
and 37.5°C. Introduce one tablet in each
vessel and operate the apparatus as per above conditions.
Chromatographic
system:
Column : C18 (25cm x 4.6mm), 5 µm
Flow rate : 1.0ml per minute
Detection :
292nm
Injection volume : 20µl
Column temperature : Ambient
Mobile
phase:
Methanol: Acetonitrile with 0.5%
Triethylamine (95:5).
Standard Preparation:
Dissolve accurately about 15mg of dapoxetine
hydrochloride WS & 25mg of sildenafil citrate WS in 50ml dry volumetric
flask. Add sufficient dissolution media to dissolve then dilute to 50 ml with
dissolution media. Dilute 5ml of above solution to 100ml with mobile phase.
Sample
preparation:
Set the parameters of the instrument as
mentioned above. Place one tablet each in six different vessels and operate the
apparatus for 45min. After 45 min, withdraw the solution from a zone midway
between the surface of the dissolution medium and top of the paddle, not less
than 1 cm from the vessel wall and filter. Filter through a 0.45-μm pore size
nylon membrane. Sonicate for 10min and further diluted 5ml of above solution to
20ml with mobile phase.
Procedure:
Separately inject blank and six replicate
injections of standard solution. Then inject test solution once and record the
chromatogram for all injections.
System
suitability test:
The relative standard deviation
determine from the respective standard solution in six replicate injections is
not more than 2.0%.
Calculation:
For Sildenafil Citrate:
Avg area of sample x weight of standard x 5 x
900 x 20 x potency of std (as is) x 100
---------------------------------------------------------------------------------------------------------------------
Avg area of standard x 50 x 100 x Label claim
x 5 x 100
For
Dapoxetine Hydrochloride:
Avg area of sample x weight of standard x 5 x
900 x 20 x potency of std (as is) x 100
-----------------------------------------------------------------------------------------------------------
Avg area of standard x 50 x 100 x Label claim
x 5 x 100
