Erythromycin enteric recrystallized agglomerates for Directly Compressible Tablets

The purpose of this research work was to obtain directly compressible enteric recrystallized agglomerates of erythromycin containing enteric polymers by emulsion solvent diffusion technique. Selected solvent for the process includes the best solvent (ethyl alcohol), non-solvent (distilled water) and bridging liquid (chloroform) according to their solubility in different organic solvent. The different enteric coating polymers like cellulose acetate phthalate (CAP), Eudragit S100 and Eudragit L100 were used in the crystallization system. The impact of these enteric coating polymers in drug: polymer ratio 1:0.25 and 1:0.5 on the release of erythromycin in 0.1N HCl were studied. The other physicochemical properties like flowability and packability were also studied. There is significant improvement in flowability and packability of enteric recrystallized agglomerates as compared to the raw crystals of erythromycin. The enteric recrystallized agglomerates having drug: polymer ratio 1:0.5 shows below 10% release of erythromycin in 0.1N HCl therefore selected for tablet preparation. The directly compressed tablets of these optimized enteric recrystallized agglomerates were prepared with microcrystalline cellulose (Avicel pH 102) and lactose monohydrate (Flowlac 200) as diluents. These prepared tablets shows below 10% release of erythromycin in 0.1N HCl and above 80% in phosphate buffer pH 6.8 which indicate that these tablets complies the release pattern as per the official pharmacopeia.