A Comparative Study on the Effect of Hydroxypropyl Methylcellulose F4M and Eudragit^® E PO on the Physicochemical Properties of Taste-Masking Microparticles

The objective of this study was to investigate the effect of polymers and their content level on the taste-masking efficiency of spray-dried microparticles. Diclofenac sodium (DS) was used as a model drug, owing to its bitter taste. Hydroxypropyl methylcellulose F4M (HPMC F4M) and Eudragit® E PO were involved in the study as a hydrophilic and a pH-responsive polymer, respectively. The taste-masked DS microparticles with the drug:polymer ratios of 1:1, 1:2 and 1:4 were prepared by the spray-drying technique. The collapsed hollow sphere HPMC F4M based-microparticles was observed meanwhile spray-dried Eudragit® E PO based-microparticles were spherical. Loading capacity of both polymer based-microparticles decreased regarding to the increment of drug:polymer ratio. The Eudragit® E PO based-microparticle in the ratio of 1:4 provided the highest loading efficiency as 91.97%. According to the simplified dissolution testing, the taste-masking ability of HPMC F4M and Eudragit® E PO based-microparticles increased upon the increase of drug:polymer ratio. Drug release at the first 5 minutes from dissolution profiles, tested by type II dissolution apparatus, of the Eudragit® E PO based-microparticles was delayed compared to HPMC F4M based-microparticles. Therefore, it could be assumed that Eudragit® E PO was a promising taste-masking polymer for DS with a pleasant taste.