Randomized, single dose, four period, cross-over open-label study to evaluate the pharmacokinetic parameters of 200 mg pirfenidone capsule versus pure pirfenidone 200 mg capsule (excluding excipients) versus 200 mg pirfenidone tablet versus 267 mg pirfenidone capsule in 32 healthy adults under fasting conditions

INTERVENTION: 32 healthy participants will be randomly allocated, in a four‐way cross‐over fashion, to receive a single dose of the following oral treatments: Treatment A: one capsule containing 200 mg pirfenidone Treatment B: one capsule containing 200 mg pirfenidone without excipients (pure pirfenidone) Treatment C: one tablet containing 200 mg pirfenidone Treatment D: one capsule containing 267 mg pirfenidone Each treatment will be administered orally with 240 ml of water. There will be a washout period of 7 days between all treatments Participants will be required to fast overnight (for at least 10 hours) before dosing and for 4 hours thereafter. CONDITION: idiopathic pulmonary fibrosis PRIMARY OUTCOME: To determine the pharmacokinetic parameters (Cmax, AUCt, AUCinf, Tmax) of pirfenidone and compare them between all four treatment groups SECONDARY OUTCOME: To monitor and compare the safety and tolerability of pirfenidone amongst the different treatment groups. This is a composite secondary outcome. ; The safety evaluation will consist of recording spontaneously reported adverse events and by measurements of vital signs (blood pressure, heart rate, respiratory rate, and temperature). INCLUSION CRITERIA: Healthy subjects, males and females aged 18 to 50 years of age. Females must be sterile or using adequate contraception. Participants must not have taken any prescription medications for at least 14 days or over‐the‐counter medications for at least 7 days before the start of each study phase, with the exception of oral contraceptives and the study medication. All subjects must be deemed healthy on the basis of a medical history, physical exam (including vital signs and ECG recording), urinalysis, and blood biochemical and haematological examinations.