Quasi emulsion spherical crystallization technique based environmentally responsive Tulsion® (pH dependent) microspheres for colon specific delivery

Ph-dependent sustained-release tulsion® microspheres bearing clarithromycin were prepared using quasi-emulsion solvent diffusion method with thermocoat l 30 d 55 as a release retardant. both,clarithromycin and thermocoat l 30 d 55,were found to be non-hemolytic during in vitro toxicity assay against human red blood cells. ratiometric optimization of different solvents using phase diagrams was performed on amount of good solvent,bridging liquid,dispersing liquid and poor solvent. the developed microspheres were evaluated for the recovery (67.27 ± 3.3%),average particle size (52.0 ± 0.46 μm) and encapsulation efficiency (61.0 ± 3.1%). scanning electron microscopy and transmission electron microscopy revealed that the microspheres were smooth in surface and spherical in shape,respectively. the drug release study was conducted at different ph of git and it gave a ph dependent release for clarithromycin. the bioavailability study revealed increased auc (2 fold) and half-life (1.2 fold) of microspheres as compared to plain drug. the manuscript reported the debut work on thermocoat l 30 d 55 based novel drug delivery system,the polymer is safe to be used,quasi emulsion spherical crystallization technique is a good technique to prepare microspheres,the prepared microspheres provides sustain release profile as well as targeting to colon. © 2015 faculty of health and social studies,university of south bohemia in ceske budejovice. published by elsevier sp. z o.o. all rights reserved.