Biochemical and physical actions of hyaluronic acid delivered by intradermal jet injection route

Pharmacotherapy for Keloids and Hypertrophic Scars

Keloids (KD) and hypertrophic scars (HTS), which are quite raised and pigmented and have increased vascularization and cellularity, are formed due to the impaired healing process of cutaneous injuries in some individuals having family history and genetic factors. These scars decrease the quality of life (QOL) of patients greatly, due to the pain, itching, contracture, cosmetic problems, and so on, depending on the location of the scars. Treatment/prevention that will satisfy patients' QOL is still under development. In this article, we review pharmacotherapy for treating KD and HTS, including the prevention of postsurgical recurrence (especially KD). Pharmacotherapy involves monotherapy using a single drug and combination pharmacotherapy using multiple drugs, where drugs are administered orally, topically and/or through intralesional injection. In addition, pharmacotherapy for KD/HTS is sometimes combined with surgical excision and/or with physical therapy such as cryotherapy, laser therapy, radiotherapy including brachytherapy, and silicone gel/sheeting. The results regarding the clinical effectiveness of each mono-pharmacotherapy for KD/HTS are not always consistent but rather scattered among researchers. Multimodal combination pharmacotherapy that targets multiple sites simultaneously is more effective than mono-pharmacotherapy. The literature was searched using PubMed, Google Scholar, and Online search engines.

Needle-Free Jet Injection of Poly-(Lactic Acid) for Atrophic Acne Scars: Literature Review and Report of Clinical Cases

Acne scars, particularly atrophic ones, present a persistent challenge in cosmetic medicine and surgery, requiring extended and multifaceted treatment approaches. Poly-(lactic acid) injectable fillers show promise in managing atrophic acne scars by stimulating collagen synthesis. However, the utilization of needle-free injectors for delivering poly-(lactic acid) into scars remains an area requiring further exploration. In this article, a summary of the latest advancements in needle-free jet injectors is provided, specifically highlighting the variations in jet-producing mechanisms. This summary emphasizes the differences in how these mechanisms operate, offering insights into the evolving technology behind needle-free injection systems. The literature review revealed documented cases focusing on treating atrophic acne scars using intralesional poly-(lactic acid) injections. The results of these clinical studies could be supported by separate in vitro and animal studies, elucidating the feasible pathways through which this treatment operates. However, there is limited information on the use of needle-free jet injectors for the intradermal delivery of poly-(lactic acid). Clinical cases of atrophic acne scar treatment are presented to explore this novel treatment concept, the needle-free delivery of poly-(lactic acid) using a jet pressure-based injector. The treatment demonstrated efficacy with minimal adverse effects, suggesting its potential for scar treatment. The clinical efficacy was supported by histological evidence obtained from cadaver skin, demonstrating an even distribution of injected particles in all layers of the dermis. In conclusion, we suggest that novel needle-free injectors offer advantages in precision and reduce patient discomfort, contributing to scar improvement and skin rejuvenation. Further comprehensive studies are warranted to substantiate these findings and ascertain the efficacy of this approach in scar treatment on a larger scale.

Home-Use Hyaluronic Acid Jet Injectors: Unreliable and Unsafe

BACKGROUND

Needle-free hyaluronic acid (HA) jet injectors are gaining popularity for rejuvenation treatment. The devices are widely available online and are used for self-injection or in beauty salons by nonphysicians. However, little is known about their performance and safety.

OBJECTIVE

To explore the injection efficiency and cutaneous biodistribution patterns administered with home-use compared with medical jet injectors and to assess safety aspects.

MATERIALS AND METHODS

The authors injected HA into ex vivo human skin with 4 home-use and 2 medical injectors. The intracutaneous dose of HA was calculated, and the cutaneous biodistribution of HA was assessed using a 3-dimensional Fluorescent Imaging Cryomicrotome System (3D-FICS). Safety aspects were evaluated based on the presence of a manual, CE (conformité européenne) mark, and sterility.

RESULTS

The intracutaneous dose delivered by the home-use injectors was markedly lower compared with the medical injectors. 3D imaging for home-use injectors showed superficial epidermal distribution with low distribution volumes. For medical injectors, volumes were substantially larger and mainly middermal. All evaluated safety aspects were lacking.

CONCLUSION

Results of this study suggest that the specific combinations of home-use injectors and HA used in this study are unreliable and unsafe, which casts doubts on the performance of these treatments in general.

Needle-free electronically controlled jet injection with corticosteroids in recalcitrant keloid scars: a retrospective study and patient survey

First-line treatment of keloids consists of intralesional needle injections with corticosteroids, but generally entails multiple painful sessions, resulting in variable clinical outcomes. Novel needle-free jet injectors may facilitate more effective and patient-friendly dermal drug delivery. Here, we evaluated the effectiveness, tolerability and patient satisfaction of intralesional triamcinolone-acetonide (TCA) treatment in recalcitrant keloids using an electronically controlled pneumatic injector (EPI). A retrospective study was conducted in recalcitrant keloid patients with a history of severe pain during needle injections who received three sessions of EPI + TCA. Outcome measures included Patient and Observer Scar Assessment Scale (POSAS), Global Aesthetic Improvement Scale (GAIS), treatment-related pain (NRS), adverse effects, and patient satisfaction (survey). Ten patients with in total 283 keloids were included. The POSAS score significantly improved at follow-up and GAIS was reported as '(very) improved' for all patients. EPI + TCA was well-tolerated with a significantly lower NRS pain score compared to needle + TCA (pilot treatment). Only minor adverse effects occurred, and 90% of patients preferred EPI over needle treatment. EPI + TCA is an effective and tolerable treatment for patients with recalcitrant keloids. The minimal treatment-related pain and high patient satisfaction makes it a promising treatment for patients with needle-phobia and/or severe pain during needle injections.

In vivo dermal delivery of bleomycin with electronic pneumatic injection: drug visualization and quantification with mass spectrometry

BACKGROUND

Intralesional bleomycin (BLM) administration by needle injection is effective for keloids and common warts but has significant drawbacks, including treatment-related pain and highly operator-depended success rates. Electronic pneumatic injection (EPI) is a promising, less painful, needle-free delivery method that potentially enables more precise and controlled dermal drug delivery. Here, we aimed to explore the cutaneous pharmacokinetics, biodistribution patterns and tolerability of BLM administered by EPI in vivo.

RESEARCH DESIGN AND METHODS

In a pig model, EPI with BLM or saline (SAL) were evaluated after 1, 48 and 216 hours. Mass spectrometry quantification and imaging were used to assess BLM concentrations and biodistribution patterns in skin biopsies. Tolerability was assessed by scoring local skin reactions (LSR) and measuring transepidermal water loss (TEWL).

RESULTS

Directly after BLM injection a peak concentration of 109.2 µg/cm³ (43.9-175.2) was measured in skin biopsies. After 9 days BLM was undetectable. EPI resulted in a focal BLM biodistribution in the mid-dermal delivery zone resembling a triangular shape. Mild LSRs were resolved spontaneously and TEWL was unaffected.

CONCLUSIONS

BLM administered by EPI resulted in quantifiable and focal mid-dermal distribution of BLM. The high skin bioavailability holds a great potential for clinical effects and warrants further evaluation in future human studies.

Needle-free jet injection-induced small-droplet aerosol formation during intralesional bleomycin therapy

OBJECTIVES

Needle-free jet injectors are frequently used in dermatological practice. Injection-generated small-droplet aerosols could be harmful upon inhalation when chemotherapeutics, like bleomycin, are used. Here, we aim to explore jet injector-induced small-droplet aerosol formation of bleomycin in relation to air ventilation and to provide safety measures for clinical practice.

MATERIALS AND METHODS

With a professional particle sensor, we measured airborne aerosol particles (0.2-10.0 µm) after electronic pneumatic injection (EPI), spring-loaded jet injection (SLI), and needle injection (NI) of bleomycin and saline (100 μl) on ex vivo human skin. Three levels of air ventilation were explored: no ventilation, room ventilation, and room ventilation with an additional smoke evacuator.

RESULTS

EPI and SLI induced significant small-droplet aerosol formation compared with none after NI (0.2-1.0 µm; no ventilation). The largest bleomycin aerosol generation was observed for the smallest particles (0.2-1.0 µm) with 673.170 (528.802-789.453) aerosol particles/liter air (EPI; no ventilation). Room ventilation and smoke evacuation led to a reduction of ≥99% and 100% of measured aerosols, respectively.

CONCLUSION

Jet injectors generate a high number of small-droplet aerosols, potentially introducing harmful effects to patients and healthcare personnel. Room ventilation and smoke evacuation are effective safety measures when chemotherapeutics are used in clinical practice.