Background: In the current investigation, oral multiple-unit microparticulate dosage form is
produced with the aim of masking the salty (or bitter) taste of etoricoxib (ETX) by incorporating it into
hydrophilic polymers (chitosan and polyethylene glycol (PEG))-based microparticles.
Objective: The influence of drug loading on ETX liberation from microparticles, the in vitro antiinflammatory
activity of ETX either in pure powder form or after its incorporation into microparticles
and the ETX taste masking by drug-loaded microparticles were studied.
Method: A temperature controlled dispersion technique was used to produce ETX-loaded chitosan-and
PEG-based microparticles. Microparticles were characterized in solid state for particle size analysis,
drug content, drug liberation, infrared spectroscopy, thin-layer chromatography and scanning electron
microscopy. The in vitro anti-inflammatory activity of free and encapsulated ETX was assessed via the
protein denaturation bioassay study and taste masking check up was performed in human volunteers.
Results: Over the tested dissolution time period of 90 min in 0.01 N HCl (pH 2.0), the increase in initial
drug loadings (30-90 mg) decreased the ETX liberation (36 ± 2% for 30 mg ETX vs. 19 ± 1% for 90 mg
ETX) from microparticles. No detectible interaction between drug and polymer was noticed but the
drug was present in an amorphous or a disordered-crystalline state within the polymer network. Furthermore,
the microencapsulation of ETX in hydrophilic polymer matrices did not alter its antiinflammatory
activity [50% inhibition (IC50) values of 21 µg/ml and 23 µg/ml were observed respectively
for ETX-loaded microparticles and ETX solution after mixing with egg albumin].
Conclusion: The usefulness of this oral microparticulate system in restraining the brain/neuro plasticity
associated chronic (or residual) pain occurring at rheumatoid arthritis condition deserves further studies.