Treatment of Hypertrophic Scars with Corticoid-Embedded Dissolving Microneedles

Abstract

Hypertrophic scarring (HTS) is frequently observed after deep dermal and full-thickness skin defects. Local drug delivery in HTS has been shown more effective compared to other (minimally) invasive treatments. Disadvantages being operator-dependency and non-uniform drug distribution. Moreover, injections are painful and difficult when confronted with extensive scars or HTS in children. Corticoid-embedded dissolving microneedles (CEDMN) were developed that provide painless skin penetration and direct dermal drug delivery. Hyaluronic acid-based DMN and CEDMN patches were utilized. Structural analysis was performed via nuclear magnetic resonance (NMR) spectroscopy while gel permeation chromatography (GPC) was applied to determine chain length (molar mass) and dispersity of hyaluronic acid. Mechanical properties were evaluated by compression testing. Five burn victims with HTS were included. For each individual, three comparable scars were chosen. One control scar was left untreated. Two scars were treated with either 600 or 800 µm CEDMN patches. Patients were treated monthly for 4 months. Treatment with 800 µm CEDMN was initiated after 8 weeks. Assessor-blinded POSAS was registered. Hydration, evaporation, color and elasticity were recorded. The physico-chemical characterization suggests that the mechanical properties enable skin penetration and adequate drug delivery. Patients experienced the therapy as painless. According to the POSAS, all scars improved over time. However, the scars that were treated with CEDMN patches improved faster and with increased increment. The 800 µm CEDMN ensured the fastest POSAS-decrease. Hyaluronic acid-based CEDMN patches are valuable alternatives to intracicatrical injections, as they offer a painless and effective method for administering corticosteroids in HTS.

Dissolving microneedles for effective and painless intradermal drug delivery in various skin conditions: A systematic review

“…Given their positive results, this technique is of great interest to improve the comfort of patients with extensive abnormal scar formation requiring intralesional injection since these procedures inflict a relatively high amount of pain, reflected by the significant difference in visual analog scale (VAS) scores 40 . A pilot study on the effects of CEDMN for hypertrophic scarring was recently published with promising results, but was not included in this review due to the date of publication 6 …”

“…40 A pilot study on the effects of CEDMN for hypertrophic scarring was recently published with promising results, but was not included in this review due to the date of publication. 6 A recent review by How et al 17 biocompatibility. 7,17 Promising therapies are inbound.…”

“…Intra‐ and transdermal delivery is considered profoundly safe, maintains a steady plasma concentration and avoids the significant hepatic first‐pass metabolism effect which limits the biological availability in enteral administration 1–4 . Parenteral administration via cutaneous penetration is considered to be painful and when done frequently harbors the risk of infection, is inconvenient, and reduces patient compliance 2,5,6 . Topical therapy, including but not limited to lotions, creams and gels, is therefore often the preferred method of drug administration in patients since the local drug load is increased and side effects are reduced compared to systemic administration 3,7 .…”

“…[1][2][3][4] Parenteral administration via cutaneous penetration is considered to be painful and when done frequently harbors the risk of infection, is inconvenient, and reduces patient compliance. 2,5,6 Topical…”

Comparison of Glyaderm with different dermal substitute matrices in a porcine wound model

“… 1 The results obtained with this standard surgical technique are less favorable in terms of contraction and scar quality, mainly due to the lack of dermis. 2 , 3 , 4 , 5 , 31 Several materials for dermal replacement have been developed. These substitutes can be placed underneath the STSG and serve as a scaffold into which cells can infiltrate and repair the wound, ultimately resulting in less scar tissue formation and contractures.…”