Dissolution test was carried out according to the united state pharmacopeia (USP) Type II dissolution apparatus paddle method. Three different dissolution media were use die 1.2 acidic buffer.4.5 acetate buffer and 6.8 phosphate buffer (900mL). Dissolution medium was poured into the vessel and temperature was equilibrated to 37±0.5ºC.The paddle was set to rotate at a given speed. Six tablets from each batch of brand was tested.
Ciprofloxacin
Preparation of standard calibration curve for Ciprofloxacin
For the standard solution, 20 mg ciprofloxacin RS was weighed and dissolved in 50ml of distilled water suitably diluted to produce a 0.016mg/ml (16μg/ml) of final concentration of working solution. The above solution was serially diluted to get the solution of the following concentration, 0.016, 0.128, 0.0096, 0.0064 mg/ml. The absorbance of the above solution was measured and then calibration curve was obtained by drawing a graph of absorbance against concentration.
Sample preparation
Aliquots of 5mls were withdrawn at the intervals of 5, 10, 20, 30, 45 and 60min, and the volumes withdrawn, replaced with fresh dissolution medium. The sample was filtered, and 3ml of filtrate was further diluted as working solution (16.66μg/ml). The absorbance was measured at 276 nm.
Ibuprofen
Preparation of standard calibration curve for Ibuprofen
For standard 10 mg of ibuprofen was taken in a 100 ml volumetric flask and makes up the volume with buffer solution and named it stock solution, its concentration was 0.1 mg/ml. From the above solution 4,6,8,10 and 12ml was taken in 100ml volumetric flask and makes up the volume. Its concentration was 0.004, 0.006, 0.008, 0.01 and 0.012mg/ml. Absorbance of the sample was taken at 221nm in a UV-visible. The values of absorbance were plotted against respective concentrations.
Sample preparation
Aliquots of 10 mL were withdrawn over periods of 10, 20, 30, 45, 60, and 90 min and replaced with the same quantity of fresh medium. The sample will be withdrawn from a zone midway between the surface of the dissolution medium and the top of the rotating blade. Then the withdrawn solution was filtered, then pipettes 5ml of the filtrate and diluted to 100ml with dissolution media to get the concentration of 0.01mg/ml.
Griseofulvin
Preparation of standard calibration curve for Ibuprofen
For standard solution 66 mg of Griseofulvin was taken in a 100 ml volumetric flask and makes up the volume with 4:1 methanol and water solution and then 1ml was withdrawn from the above solution and diluted to 100ml with the same solution to get the solution with 0.0044mg/ml concentration. From the above solution 3.3ml, 6.7ml,10ml,13.3ml,16.7ml and 20ml was taken in 25ml volumetric flask and makes up the volume. Its concentration was 0.00088, 0.00176, 0.00264, 0.00352, 0.0044, 0.00528 and 0.0066mg/ml. Absorbance of the sample was taken at 291nm in a UV-visible spectrophotometer. The values of absorbance were plotted against respective concentrations.
Sample preparation
Aliquots of 5ml of sample was withdrawn over a period of 10, 20, 30,45, 60, 90 and 120 min and replaced with the same quantity of fresh medium. Then filter the withdrawn sample, pipette 1ml of the filtrate and dilute to 25ml with 4:1 solution of methanol and water, and pipette again 5ml and dilute to 25ml get the concentration of 0.0044mg/ml. Then measure the absorbance at 291nm.
Erythromycin
Preparation of standard calibration curve for erythromycin
For preparation of standard solution 0.33 mg of Erythromycin stearate was taken in a 100 ml volumetric flask and makes up the volume with buffer solution and named it stock solution, its concentration was 0.33 mg/ml. Serial dilution was made from the above solution to get the solutions with the following concentration;0.33, 0.28, 0.224 ,0.160 ,0.122 ,0.056mg/ml. Absorbance of the sample was taken at 221nm in a UV-visible. The values of absorbance were plotted against respective concentrations.
Sample preparation
Aliquots of 10mls of the sample solutions was withdrawn at 5,10,15,30,45 and 60 minutes respectively.5ml of the filtered portion of the test solution was transferred to 25ml volumetric flask ,2ml of water was added and allowed to standard for 5 min with intermittent swirling,15ml of 0.25 N sodium hydroxide was added and diluted with the medium to the volume, the solution was Heated to 600C for 5minutes and allowed to cool. The absorbance was determined at 236nm.
Furosemide
Preparation of standard calibration curve for Furosemide
For standard solution preparation 10mgof Furosemide was weighed andtransferred to100ml volumetric flask and dissolved with dissolution media. Then16.7mlof the solution was taken and diluted to get 0.0167mg/ml. Then the above solution was diluted to obtain the solutions with the following concentrations: 0.004,0.0066,0.0088 ,0.011,0.0133 and 0.0167mg/ml. Absorbance of the solution was taken at 274nm in a UV-visible. The values of absorbance were plotted against respective concentrations.
Sample preparation
For preparation of sample solution 10 mL was withdrawn over a period of 10, 20, 30,45, 60, and 90 min and replaced with the same quantity of fresh medium. Thenthe withdrawn sample was filtered, pipetted 5ml of the filtrate and diluted to 20ml with dissolution media to get the concentration of 0.011mg/ml. The absorbance was determined at 274nm
Statistical analysis
A simple model approach of similarity factor(f2)was used to compare dissolution profiles of the innovator and generic medicine.
The similarity factor (f2 ) is a logarithmic reciprocal square root transformation of the sum of squared error and is a measurement of the similarity in the percent (%) dissolution between the two curves.
Compliance criteria
The product was considered to be similar to innovator brand if the similarity factor was between 50-100 therefore the product passed the test.