Design, development, and optimization of orally disintegrating tablets of etoricoxib using vacuum-drying approach

Etoricoxib is a cyclooxygenase 2 (COX-2) inhibitor that selectively inhibits the COX-2 enzyme and decreases the incidences of side effects associated with these agents. It is commonly prescribed for acute pain, gouty arthritis, and rheumatoid arthritis. Conventional tablets of etoricoxib are not capable of rapid action, which is required for faster drug effect onset and immediate relief from pain. Thus, the aim of the present investigation is to formulate orally disintegrating tablets (ODTs) of etoricoxib. A combination of the superdisintegrants with a sublimation technique was used to prepare the tablets. Tablets were prepared using a direct compression method employing superdisintegrants such as low substituted hydroxylpropyl methyl cellulose (L-HPMC), low substituted hydroxyl-propyl cellulose (L-HPC), crospovidone, croscarmellose sodium, and sodium starch glycolate. Tablets of etoricoxib prepared using L-HPC exhibited the least friability and disintegration time (approximately 65 s). To decrease the disintegration time further, a sublimation technique was used along with the superdisintegrants for the preparation of ODTs. The use of sublimating agents including camphor, menthol, and thymol was explored. The addition of camphor lowered the disintegration time (approximately 30 s) further, but the percent friability was increased. A 3(2) full factorial design was employed to study the joint influence of the amount of superdisintegrant (L-HPC) and the amount of sublimating agent (camphor) on the percent of friability and the disintegration time. The results of multiple linear regression analysis revealed that for obtaining an effective ODT of etoricoxib, higher percentages of L-HPC and camphor should be used. Checkpoint batches were prepared to validate the evolved mathematical model. A response surface plot is also presented to graphically represent the effect of the independent variables on the percent of friability and the disintegration time. The approach using the optimization technique helped to produce a detailed understanding of the effects of formulation parameters.