Compatibility studies:
IR Studies: IR spectra for pure drug Montelukast sodium and formulations CP2 and CP3 powdered tablets were recorded in Infrared spectrophotometer with KBr pellets.
Evaluation of fast dissolving tablets of Montelukast sodium:
Pre-compression Parameters: The tablet blends were evaluated for their bulk density, tapped density, Carr’s index and flow properties.
Post-compression Parameters:
Hardness test: The hardness of the tablets was determined using Pfizer hardness tester. It is expressed in kg/cm2. Six tablets were randomly picked from each formulation and the mean and standard deviation values were calculated. Friability: A friability test was conducted on the tablets using Friabilator. A friability test was conducted on the tablets using Friabilator. Twenty tablets were selected from each batch and any loose dust was removed with the help of a soft brush. The tablets were initially weighed (Winitial) and transferred into Friabilator. The drum was rotated at 25 rpm for 4 min after which the were removed. Any loose dust was removed from the tablets as before and the tablets were weighed again (Wfinal). The percentage friability was then calculated by,
F = [(Winitial- Wfinal)/ Winitial] X 100
% Friability of tablets less than 1% is considered acceptable.
Weight variation: The weight variation test was conducted by weighing 20 randomly selected tablets individually, calculating the average weight and comparing the individual tablet weights to the average. The specification of weight variation is 10%.
Estimation of drug content [27]: Five tablets weighted and crushed in a mortar then weighed powder contain equivalent to 10 mg of drug transferred in 100ml of 0.5% of SLS [sodium lauryl sulfate ] solution to give a concentration of 100μg/ml. Take 15ml of this solution and diluted it upto 100ml with 0.5% of SLS solution to give a concentration of 15μg/ml. Absorbance measured at 342nm using UV-Visible Spectrophotometer.
Disintegration time [28]: Tablet disintegration is an important step in drug absorption. The test for disintegration was carried out in Electrolab USP disintegration test apparatus. It consists of 6 glass tubes which are 3 inches long, open at the top, and held against a 10 mesh screen, at the bottom end of the basket rack assembly. To test the disintegration time of tablets, one tablet was placed in each tube and the basket rack was positioned in a 1 liter beaker containing 0.5% of SLS in water at 37°C ± 1°C such that the tablet remains 2.5 cm below the surface of the liquid. The time taken for the complete disintegration of the tablets was noted.
Wetting time: 10 ml of distilled water containing Eosin, a water soluble dye was placed in a petri dish of 10 cm diameter. Tablets were carefully placed in the centre of the petri dish and the time required for water to reach the upper surface of the tablet was noted as the wetting time. The test results are presented as mean value of three determinations.
Water absorption ratio [29]: A piece of tissue paper folded twice was placed in a small Petri dish containing 6 ml of water. A tablet was put on the paper and the time required for complete wetting was measured. The wetted tablet was then weighed. Water absorption ratio indicated by R, which is calculated by using the below mentioned equation.
In-vitro release [30-32]: The in-vitro dissolution studies of FDT were performed at 37 ± 0.5°C using 0.5% w/v aqueous solution SLS in USP II paddle method at 50 rpm. 5 mL of filtered aliquot was manually withdrawn at pre-determined time intervals and replaced with 5 mL of fresh 0.5% SLS solution maintained at the same temperature. The samples were analyzed at 342nm using a UV spectrophotometer.
Details of dissolution test:
Dissolution test apparatus : USP type II
The stability study [33] of the tablets was carried out according to International conference onHarmonization guidelines for zone III and IV. The formulations were stored at 25°C/ 60% and 40°C / 75 % RH for three months by storing the samples in stability chamber (Thermo Lab, Mumbai).