Design, development and in-vitro evaluation of diclofenac taste-masked orodispersible tablet formulations

Context: Fast onset of action is prerequisite for acute pain medication. A palatable orodispersible medicine of diclofenac providing rapid analgesic effect should improve patient compliance and treatment. Objective: In the present study, diclofenac taste-masked orodispersible tablets (ODTs) with fast release characteristics were developed. Different taste-masking approaches and formulation concepts were screened in vitro for candidate selection. Materials and methods: Diclofenac was used as free acid. Five taste-masked microgranule formulations were prepared by wet granulation and/or coating processes, and compressed to ODTs. Citric acid (pH-modifying agent) and Eudragit (R) E PO (amino methacrylate copolymer) were used as taste-masking agents. Evaluation criteria were (i) disintegration time, (ii) processability and (iii) in-vitro dissolution profiles in simulated saliva (pH 7.4, 5 mL, 3 min) and compendial pH-change media (paddle, 50 rpm). The prototypes were compared to reference ODTs (without taste-masking). Most suitable ODT prototypes were selected and further evaluated for taste-masking efficiency using an electronic tongue. Results and discussion: In simulated saliva, the drug was slower released from the prototypes (between 1.1% and 15.5%) than from reference ODTs (23.7%). Less dissolved particles are thus expected in vivo for taste perception. Two ODT prototypes showed fast and complete drug release in phosphate buffer. The formulation providing the most efficient taste-masking was selected guided by electronic tongue data. Conclusion: A novel palatable and fast acting diclofenac ODT formulation was successfully developed. Formulation design, development and in-vitro evaluation used in this study may serve as rational approach for manufacturing taste-masked orodispersible dosage forms.