Pilocarpine Microneedles for Sweat Induction (PMN-SI)

A Pilot Study to Compare the Efficacy of Pilocarpine Microneedles With Iontophoresis Method for Sweat Induction in Healthy Human Subjects

The investigators want to test in this non-randomized clinical trial a new method of administrating Pilocarpine medicine into the skin during the Sweat testing process that does not use any electrical current.

Sweat collection tests are done when a patient is suspected of having cystic fibrosis. This procedure for collection of sweat samples is called the Sweat Test and the measurement of sweat chloride concentration from the collected sweat sample is the gold standard for the diagnosis of Cystic Fibrosis. When the sweat test is performed for patients in a hospital lab, the standard method uses a small electrical current to push pilocarpine medicine into the skin of the forearm, after which sweat is collected for testing. However, many people do not make enough sweat during this standard method of testing and have to come back for repeated testing. The investigators want to test a new method of putting Pilocarpine medicine into the skin during the Sweat testing process that does not use any electrical current. The testing will be done once for every participant and no further follow up or additional testing is needed. The study team plans to invite healthy adults who are not taking any medicines to participate through a flyer posted in Emory Children's Center bulletin board. For those interested in participating, the study will be explained to them in detail and an informed consent will be obtained. The subjects will be asked to sit for 45 minutes on a chair as the study related procedures are completed on their arms. The right forearm will be used for pilocarpine iontophoresis method and the left forearm will be used for microneedle-based stimulation method for a period of 5 minutes. An additional microneedle control patch (without any Pilocarpine) will be placed on the left forearm to make sure that there are no skin changes from the microneedles. After the first 5 minutes, the sweat collection devices (Macroduct) will be placed on both forearms to collect sweat samples from each site. After the completion of this 30-minute collection phase, the Macroduct collectors will be removed by the study team and the subject testing will be complete. The study team will store the sweat samples to measure their chloride concentration at the end of the enrollment phase of the study. This study will be conducted in a research room at Emory Children's Center and no compensation will be provided to the participants. At the end of the study, the research team will compare the two methods based on how much sweat was produced in each individual's arms with either of these methods. The results of this study will help to improve the current technique of sweat testing and help reduce the need for repeated testing in patients being evaluated for Cystic Fibrosis.

Participants will receive in their left forearm the microneedle patch. Upon application to skin, the MNs penetrate into the skin's upper layers and dissolve in the interstitial fluid to release the loaded drugs. MN patches are painless and can be administered with little or no training.

Participants will receive in their right forearm the pilocarpine iontophoresis. Uses a gel disc containing Pilocarpine that drives the medication into the skin with a small electric current (iontophoresis) followed a 30-minute period of sweat collection.

Each microneedle (MN) patch contains an array of solid, water-soluble, micron-scale needles that encapsulate the medication (Pilocarpine). The patch form can be placed directly on the skin.

Pilocarpine Iontophoresis is a process of transdermal pilocarpine delivery by use of a voltage gradient on the skin. An agar gel disc containing pilocarpine is placed under the electrodes which are connected to the Macroduct 3700 Sweat Inducer device.

Sweat weight in mg collected after application of Pilocarpine Microneedle patch was compared to the forearm of healthy adult subjects with that of standard of care method using pilocarpine iontophoresis

Sweat chloride concentrations will be measured from the sweat samples obtained from the application of Pilocarpine Microneedle patch to the forearm of healthy adult subjects and compare them with measurements from standard of care method using pilocarpine iontophoresis.

Inclusion Criteria: Age >18 years Signed a written informed consent Not taking any medications No known medical diagnoses or chronic conditions Exclusion Criteria: Age <18 years Family history of Cystic Fibrosis History of skin disorders (eczema, psoriasis etc.) that could prevent sweat testing on forearms Current medication use