All the solvents and chemicals were used of analytical grade. Microspheres were prepared by simple emulsification – phase separation technique8 according to experimental design. Birinapant Potential variables such as stirring time, stirring speed and ratio of dispersion medium were kept constant. CP (100 mg) was dispersed

in 1% w/v CS solution. The resultant mixture was extruded through syringe (NO: 20) to 100 ml liquid paraffin (1:1 ratio of heavy and light) containing 0.2% DOSS under stirring at 1000 rpm. After 15 min, crosslinked by GA (25% aqueous solution) and crosslinking time kept for 1 h. The CP:CS ratio (1:2, 1:3, 1:4) and amount of GA (3,4,5 ml) were varied in batches F1 – F9 as shown in Table 1. Microspheres were filtered, washed with petroleum ether and water and allowed to air dry at room temperature for 24 h. Microspheres

(100 mg) were crushed in a glass mortar and suspended in 20 ml of SGF (pH 1.2). After 24 h, the solution was filtered through 0.45 μm membrane filter, and the filtrate was analyzed for drug Selleck PD0332991 content at 263 nm.9 Drug entrapment efficiency = (practical drug content/theoretical drug content) × 100, results were shown in Table 1. Optical microscopy method10 was used to determine the particle size of microspheres. 100 microspheres were counted using optical microscope (Labomed CX RIII, Ambala, India). The average particle size was determined by using the Edmondson’s equation Dmean = Ʃnd/n, where, n = number of microspheres, d = mean size range. The particle sizes were shown in Table 1. To study the surface morphology, the formulation (F7) subjected to scanning electron microscopy, the micrograph depicted in Fig. 1. 50 mg of microspheres were allowed for swelling in SGF (pH 1.2) for 4 h, the excess adhered liquid was removed by blotting with filter paper and weighed.11 and 12 Swelling index (SI) = Ws−Wo/Wo, where, Wo – initial weight of the dry microspheres, Ws – final weight of swollen microspheres, results were shown in Table 1. A strip of rat stomach mucosa 1 cm × 1 cm

was mounted on a glass slide and accurately weighed microspheres were placed on the tissue,10 kept in a desiccator at 90% relative humidity for 15 min to Astemizole allow the microspheres to interact with the membrane and by fixing at an angle of 45° relative to the horizontal plane. SGF (pH 1.2) was peristaltically pumped at a rate of 2 ml/min over the tissue. The washings were filtered and dried. Percentage mucoadhesion = Wo–Wt/Wo, Where, Wo = weight of microspheres applied, Wt = weight of microspheres leached out, results were shown in Table 1. Microspheres equivalent to 100 mg of CP were filled in hard gelatin capsules, dissolution was performed using USP type II apparatus (Electrolab, TDT) at 37 ± 0.5 °C, rotational speed of 50 rpm in 900 ml SGF (pH 1.2) for 12 h. Samples (5 ml) were withdrawn at predetermined time intervals and equally replaced with fresh dissolution medium, filtered through 0.