Abstract: The present invention relates to a method of preparation of metaxalone comprising reaction of triglycidyl isocyanurate (TGIC) with m-xylenol, characterized in that said reaction is carried out in a solvent mixture comprising an aprotic polar solvent with dielectric constant greater than or equal to 30 and at least one other solvent selected from the group comprising apolar solvents and aprotic polar solvents with dielectric constant below 30 said solvent mixture comprising from 5 to 40 wt. % of said first solvent and from 95 to 60 wt. % of said second solvent, adding the TGIC at a temperature between 30° C. and 50° C., and after adding the TGIC, raising the temperature of the reaction solution to a value between 80° C. and 180° C. in a time between 120 and 180 minutes at a rate of increase not greater that 1.25° C. per minute. The invention also relates to a metaxalone with a reduced content of impurities derived from incomplete reactions and/or side reactions of the method of production.