Evaluation Of Pellets Case Study

6.4. Evaluation of Pellets:

6.4.1. Angle of repose:

Flow ability of pellets was determined by calculating angle of repose by funnel method. A funnel with 10 mm inner diameter of stem was fixed at a height of 2 cm over the platform. About 5 gm of sample was slowly passed along the wall of the funnel till the tip of the pile formed and touches the bottom of the funnel. A circle was designed around the sample base and the radius of the powder cone was measured. Angle of repose was determined from the average radius using the following formula14, 15 θ = tan-1 (h/r) Where, θ = angle of repose h = height of the pile r = average radius of the powder cone.

6.4.2. Bulk Density:

Apparent bulk density was determined by placing pellets into measuring cylinder and

Higuchi model94,95 [Q = KH t½]

4. Korsmeyers-Peppas model:96,97 F = (Mt/M) = Km tn

6.4.7. Drug content:

The drug content from pellet formulations was investigated; in which the quantity of pellets equivalent to 6.25 mg of dose of zolpidem tartarate was weighed and dissolved in 0.01 N HCl, sonicated for 15 minutes to dissolve it completely and then the solution of 14 ppm was prepared which was considered as a working level for the complete analysis. The absorbance was determined at the 294.5nm by UV spectrophotometer. Then the drug content was determined by comparing the absorbance of this solution with standard solution having same concentration.

6.4.8. In vitro drug release studies98:

In-vitro release of zolpidem tartarte from pellet formulations was investigated by the Paddle method (Apparatus II). The dissolution medium was 500 mL of 0.01N HCl solution at 37 ± 0.5 °C and the rotating speed was 50 rpm. At certain time intervals, 1 ml of sample was withdrawn and immediately same amount of fresh medium (37±0.50C) was replaced. The UV absorbances of samples were measured at 294.5 nm by UV spectrophotometer and drug release was calculated.

6.4.9. Scanning electron microscopy