A study found that the average difference between the pilocarpine HCL solution and Pilogel discs was -3.25 mmol/L and 0.69 mmol/L.
A pharmacy compounded pilocarpine HCL solution is a suitable alternative to Pilogel discs for the measurement of sweat chloride concentrations in cystic fibrosis screenings, according to a new study published in the Journal of Cystic Fibrosis.1
Pilogel discs, also known as Macroduct Advanced Supply Kit, are used in the diagnostic process for cystic fibrosis. Since June 2022, there has been a severe shortage of Pilogel discs in Europe due to changed medical device legislation which required a new process for additional testing and medical validation for certain devices.
“One of the major issues regarding the recertification process of Pilogel discs in [Europe] is represented by the safety data of pilocarpine,” the authors wrote. “As there [is] only one manufacturer of Pilogel discs, alternatives have to be available in case of [a] shortage. As Pilogel discs are essential in the diagnostics of cystic fibrosis to evaluate effects of the drug Kaftrio, and also in…patients who had a lung transplant, we decided to produce a Pilocarpine HCL solution to be able to sustain patient care in a proper way.”
Investigators from the University of Groningen in the Netherlands conducted a prospective study to assess the results from a pharmacy compounded pilocarpine HCL solution versus Pilogel discs for the measurement of sweat chloride concentrations. The study took place from September 1, 2022, through December 1, 2022.
The compounded pilocarpine HCL solution was created by dissolving 64 mg pilocarpine HCL in 100 ml of purified water. The Pilogel discs, obtained from the ELiTechGroup, contained 0.5% pilocarpine nitrate in solid agar gel.
The study cohort included 10 children and adults with cystic fibrosis who had an indication for a sweat test. Chloride concentrations for both the pilocarpine HCL solution and Pilogel discs were compared using a Bland-Altman analysis.
Investigators found the average difference between the pilocarpine HCL solution and Pilogel discs was -3.25 mmol/L and 0.69 mmol/L. All of the differences reported in the study were within acceptable ranges, which the authors said demonstrated an unbiased systematic agreement between the methods.
Additionally, a passing-bablok regression analysis showed that zero was enclosed with the 95% CI of the calculated intercept.
Study limitations include that there were only 10 participants and that there were no newborns. However, the authors noted that because pilocarpine solution was the gold standard for cystic fibrosis diagnosis, a large number of patients was not necessary to test agreement between the 2 products.
“[P]harmacy compounding formulations, like in this case pilocarpine HCL solution, are in case of shortage, a valuable alternative,” the authors concluded. “There is no doubt that the shortage of Pilogel discs in 2022 created very difficult situations in all cystic fibrosis centers in Europe that were using the Macroduct systems. With this study our group made an effort to overcome this situation for the future.”