The efficacy and safety of botulinum toxin-loaded detachable dissolvable microneedles for primary axilla hyperhidrosis: A pilot study

Botulinum toxin injection is a well-established treatment for primary hyperhidrosis. This study’s objective is to evaluate the efficacy and safety of botulinum toxin-loaded detachable dissolvable microneedles (BoNT-MNs), developed to circumvent the disadvantages of intradermal hypodermic-injection. This within-subject study included ten healthy adults, with HDSS 1. BoNT-MNs patches were prepared and each microneedle patch contained 15 units of onabotulinum toxin. BoNT-MNs and placebo patches were randomly applied on different sides of axilla. Iodine-starch test, dermatologists’ and patients’ satisfaction scores were assessed at baseline and weeks 1, 2, 3, 4, 8, 12, 16, 20, and 24 to evaluate onset, duration of effect, and adverse events. A total of 10 female subjects completed the trial. Notably, the scores on BoNT-MNs side showed a substantial reduction within the first week of study with the highest change of 57.14% at week 12, then subsequently returned after week 20. Dermatologists’ satisfaction scores and patients’ satisfaction scores showed statistical significance when compared between baseline and weeks 2-24 (p-value ≤ 0.001), and weeks 1-4 (p-value < 0.05), respectively. Nevertheless, iodine-starch scores were statistical insignificance between two sides through 24-week follow-up. BoNT-MNs are safe and effective for axillary sweating reduction, however, dosage, depths of penetration, loading per microneedles and number of treatments may all play roles in the efficacy of this less painful modality and should be explored in further studies.