SGJ contained 2 g/l NaCl, 3.2 g/l pepsin powder and 20 ml of 1MHCl
(British Pharmacopoeia, 2008). The componentswere diluted in 900ml
deionised water and after pH adjustment (pH 2.0), the volume was
topped up to 1 l. pH was adjusted using 1 M HCl or 1 M NaOH. This
model solution was sterilised by passage through a sterile 0.2 μm syringe
filter.