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Paper text:
floating microspheres loaded with vch were prepared by using water - in - oil ( w / o ) emulsification solvent evaporation method .
polymer ( ec ) was dissolved in mixture of dichloromethane and ethanol ( 1:1 ) .
drug was dispersed in polymer solution by stirring with high speed stirrer for 15 min .
the dispersion was slowly poured into the dispersion medium ( 250 ml ) consisting of light liquid paraffin containing 0.1% span 80 .
the system was stirred using an overhead propeller agitator ( remi equipments , india ) for a period of 34 h , to ensure complete evaporation of organic phase .
microspheres were collected by filtration and washed thrice with n - hexane and air dried .
estimation of entrapment efficiency was carried out by dissolving the microspheres in a dichloromethane and ethanol ( 1:1 ) and extracting the drug by adding same amount of dissolution medium ( 0.1n hcl ) aqueous layer was separated and analysed by uv spectrophotometer ( 1700 , shimadzu , japan ) at 255 nm .
surface morphology of microspheres was studied under scanning electron microscope ( jeol , jsm 5760 ly ) .
dsc and ftir studies were performed to check the compatibility of drug ( vch ) with ethyl cellulose using differential scanning calorimeter ( shimadzu as , japan ) and ftir ( bruker optics , germany ) .
the xrd pattern of pure drug , physical mixture and prepared microspheres were obtained using a powder diffractometer ( bruker axs d8 advance , germany ) . in vitro floatability and drug release studies
were carried out in usp type ii dissolution testing apparatus , using dissolution medium ( 0.1n hcl ) containing tween-80 ( 0.02% ) at 100 rpm . in vivo floatability study
x ray photograph of stomach was taken after administration of barium sulphate loaded floating microspheres .
floating microspheres loaded with vch were prepared by using water - in - oil ( w / o ) emulsification solvent evaporation method .
polymer ( ec ) was dissolved in mixture of dichloromethane and ethanol ( 1:1 ) .
drug was dispersed in polymer solution by stirring with high speed stirrer for 15 min .
the dispersion was slowly poured into the dispersion medium ( 250 ml ) consisting of light liquid paraffin containing 0.1% span 80 .
the system was stirred using an overhead propeller agitator ( remi equipments , india ) for a period of 34 h , to ensure complete evaporation of organic phase .
microspheres were collected by filtration and washed thrice with n - hexane and air dried .
estimation of entrapment efficiency was carried out by dissolving the microspheres in a dichloromethane and ethanol ( 1:1 ) and extracting the drug by adding same amount of dissolution medium ( 0.1n hcl ) aqueous layer was separated and analysed by uv spectrophotometer ( 1700 , shimadzu , japan ) at 255 nm .
surface morphology of microspheres was studied under scanning electron microscope ( jeol , jsm 5760 ly ) .
dsc and ftir studies were performed to check the compatibility of drug ( vch ) with ethyl cellulose using differential scanning calorimeter ( shimadzu as , japan ) and ftir ( bruker optics , germany ) .
the xrd pattern of pure drug , physical mixture and prepared microspheres were obtained using a powder diffractometer ( bruker axs d8 advance , germany ) . in vitro floatability and drug release studies
were carried out in usp type ii dissolution testing apparatus , using dissolution medium ( 0.1n hcl ) containing tween-80 ( 0.02% ) at 100 rpm . in vivo floatability study
x ray photograph of stomach was taken after administration of barium sulphate loaded floating microspheres .
particle size of optimized floating microspheres was found to be 550.0210.241 m . the percentage entrapment efficiency of prepared floating microspheres was 79.88 2.236% .
sem photograph [ figure 1 ] revealed that , microspheres were spherical , had narrow distribution and porous .
ft - ir , dsc and xrd studies [ figure 2 ] confirmed no interaction between vch and ethyl cellulose . in vitro floatability studies revealed that 90% of the microspheres were floated for more than 12 hours because of their low densities and internal voids .
the densities of floating microspheres were found less than the density of gastric fluid , therefore tended to float over gastric fluid . optimized floating microspheres exhibited 94.03% drug release at 12h .
sem images of vch loaded floating microspheres showing porous surface x ray photograph of barium sulphate loaded floating microspheres in dog
vch loaded floating microspheres can be a suitable alternative to the conventional formulation , by localizing the drug at upper git .
floating microspheres are multiple unit gastroretentive drug delivery systems . 
 valacyclovir hydrochloride ( vch ) is l - valyl ester prodrug of acyclovir . 
 vch degrades in intestinal fluid . 
 the objective was to develop floating microspheres of vch to localise the drug at upper part of git , for improved absorption . 
 floating microspheres were prepared by w / o emulsification solvent evaporation method using ethylcellulose ( ec ) as polymer . 
 particle size and % ee were 550.0210.241 m , 79.882.236% respectively . in vitro and in vivo floatability studies confirmed floating behaviour of microspheres . 
 vch loaded floating microspheres can be a suitable alternative to the conventional formulation , by localizing the drug at upper git .