Sweat induction using Pilocarpine microneedle patches for sweat testing in healthy adults.

Jonathan Yuxuan Chen, Song Li, George L Silva, Joshua D Chandler, Mark R Prausnitz, Lokesh Guglani

Journal: Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society 2024;23(1):112-119

PMID: 37236899

Full Text on Elsevier Science View on PubMed

Abstract

BACKGROUND

The sweat test using pilocarpine iontophoresis remains the gold standard for diagnosing cystic fibrosis, but access and reliability are limited by specialized equipment and insufficient sweat volume collected from infants and young children. These shortcomings lead to delayed diagnosis, limited point-of-care applications, and inadequate monitoring capabilities.

METHODS

We created a skin patch with dissolvable microneedles (MNs) containing pilocarpine that eliminates the equipment and complexity of iontophoresis. Upon pressing the patch to skin, the MNs dissolve in skin to release pilocarpine for sweat induction. We conducted a non-randomized pilot trial among healthy adults (clinicaltrials.gov, NCT04732195) with pilocarpine and placebo MN patches on one forearm and iontophoresis on the other forearm, followed by sweat collection using Macroduct collectors. Sweat output and sweat chloride concentration were measured. Subjects were monitored for discomfort and skin erythema.

RESULTS

Fifty paired sweat tests were conducted in 16 male and 34 female healthy adults. MN patches delivered similar amounts of pilocarpine into skin (1.1 ± 0.4 mg) and induced equivalent sweat output (41.2 ± 25.0 mg) compared to iontophoresis (1.2 ± 0.7 mg and 43.8 ± 32.3 mg respectively). Subjects tolerated the procedure well, with little or no pain, and only mild transient erythema. Sweat chloride concentration measurements in sweat induced by MN patches (31.2 ± 13.4 mmol/L) were higher compared to iontophoresis (24.0 ± 13.2 mmol/L). Possible physiological, methodological, and artifactual causes of this difference are discussed.

CONCLUSIONS

Pilocarpine MN patches present a promising alternative to iontophoresis to enable increased access to sweat testing for in-clinic and point-of-care applications.

Address: The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Georgia Institute of Technology, Atlanta, GA 30332, USA; Global Center for Medical Innovation, Atlanta, GA 30318, USA.; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.; Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30332, USA; Center for CF & Airways Disease Research, Children's Healthcare of Atlanta, Atlanta, GA 30322, USA.; The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Georgia Institute of Technology, Atlanta, GA 30332, USA; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA. Electronic address: [email protected].; Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30332, USA; Center for CF & Airways Disease Research, Children's Healthcare of Atlanta, Atlanta, GA 30322, USA. Electronic address: [email protected].

DOI: 10.1016/j.jcf.2023.04.014

Link outs

Free resources

Medical:

Subscription / membership required

Full Text Sources:

MeSH Terms: Adult, Child, Child, Preschool, Female, Humans, Infant, Male, Chlorides, Cystic Fibrosis, Erythema, Pilocarpine, Reproducibility of Results, Sweat