Prilling of API/fatty acid suspensions: Screening of additives for drug release modification

Current study screened additives which could modify the drug release from prills made of an active pharmaceutical ingredient/fatty acid (API/FA) suspension, without negatively influencing the processability and/or stability of the formulation. Therefore, 11 additives (i.e. emulsifiers, pore-formers and FA-based lubricants) were added in a 20% concentration to a paracetamol/behenic acid formulation. Two additives, Kolliphor® P338 and P407 provided complete drug release in less than 1 h, as their thermoreversible gel formation resulted in a disintegration of the prills. Lower Kolliphor® P338 or P407 concentrations (2.5-10%) resulted in a complete but slower drug release in 24 h as the prills no longer disintegrated and the release mechanism was dominated by pore-formation. Prills with a robust drug release profile (i.e. independent of pH and surfactant concentration of the dissolution medium) were obtained after the addition of ≥5% Kolliphor® P338 or P407 to the FA-based formulation. Based on a 6-month stability study, it was concluded that Kolliphor® P407 was a suitable additive to modify the drug release profile of API/FA suspension-based prills when formulations were stored below 25 °C at low relative humidity.