Non-Ablative Fractional Laser to Facilitate Transdermal Delivery

Construction of various lipid carriers to study the transdermal penetration mechanism of sinomenine hydrochloride

OBJECTIVE

To investigate the transdermal mechanisms and compare the differences in transdermal delivery of Sinomenine hydrochloride (SN) between solid lipid nanoparticles (SLN), liposomes (LS), and nanoemulsions (NE).

METHODS

SN-SLN, SN-LS and SN-NE were prepared by ultrasound, ethanol injection and spontaneous emulsification, respectively. FTIR, DSC, in vitro skin penetration, activation energy (Ea) analysis were used to explore the mechanism of drug penetration across the skin.

RESULTS

The particle size and encapsulation efficiency were 126.60 nm, 43.23 ± 0.48%(w/w) for SN-SLN, 224.90 nm, 78.31 ± 0.75%(w/w) for SN-LS, and 83.22 nm, 89.01 ± 2.16%(w/w) for SN-LS. FTIR and DSC showed the preparations had various levels of impacts on the stratum corneum's lipid structure which was in the order of SLN > NE > LS. Ea values of SN-SLN, SN-LS, and SN-NE crossing the skin were 2.504, 1.161, and 2.510 kcal/mol, respectively.

CONCLUSION

SLN had a greater degree of alteration on the skin cuticle, which allows SN to permeate skin more effectively.

New Insight into Nonablative 675-nm Laser Technology: Current Applications and Future Perspectives

In the nonablative laser field, a new technology that emits a 675-nm wavelength red light is emerging. A literature review was performed to examine its efficacy and safety in the treatment of skin diseases. Various databases were searched (PubMed, Google Scholar, and ClinicalTrials.gov) up to March 2023. Skin aging disorders, melasma, and acne scars were the main diseases discussed in the literature. Although the therapeutic outcomes were variable, all of the studies reported good clinical outcomes. The new 675-nm laser system, targeting collagen, is promising in the treatment of aging-related skin conditions, melasma, and acne scars.

Stem cell-derived exosomes in the treatment of melasma and its percutaneous penetration

BACKGROUND AND OBJECTIVES

Melasma is a refractory skin disease due to its complex pathogenesis and difficult treatment. Studies have found that human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exos) could serve as a novel cell-free therapeutic strategy in regenerative and esthetic medicine. It could potentially treat melasma, but the skin barrier is a challenge. In this study, we aim to explore the safety and efficacy of hUCMSC-Exos in the treatment of melasma and the means to promote its percutaneous penetration.

MATERIALS AND METHODS

In the animal study about the effect of penetration, percutaneous penetration of PKH67-labeled hUCMSC-Exos was studied under microneedles, 1565 nm nonablative fractional laser (NAFL), and a plasma named Peninsula Blue Aurora Shumin Master (PBASM) treatments, observed by confocal laser scanning microscopy. In the clinical application study, 60 patients with melasma treated in our department were divided into four groups. NAFL combined with normal saline treatment was used for Group A. Microneedles, NAFL, and PBASM combined with hUCMSC-Exos treatments were used for Groups B, C, and D, respectively. Each patient received four treatments at 1-month intervals. Assessments were done using the degree of pain posttreatment, melasma area and severity score, improvement rate, physician global assessment score, satisfaction, and complications.

RESULTS

In the animal study about the effect of penetration, hUCMSC-Exos can penetrate the deep dermis under microneedles, NAFL, and PBASM treatments. In the clinical application study, compared with Group A, Groups B, C, and D showed significantly improved therapeutic effect and patient satisfaction (p < 0.05), and there was no significant difference among Groups B, C, and D.(p > 0.05). Patients in Group B reported higher pain levels than those in the other three groups (p < 0.05); the treatment experience of patients in Group D was better.

CONCLUSION

hUCMSC-Exos can improve the symptoms of melasma safely and effectively. Compared with microneedles, NAFL and PBASM can also achieve a good effect toward promoting penetration. These findings are worthy of exploration and clinical application.

Enhancing Skin Uptake of Topical Antioxidants With 1,440-nm Nonablative Fractional Diode Laser Pretreatment

BACKGROUND

Energy-based devices, such as nonablative lasers, are a promising method to enhance the delivery and absorption of topically applied molecules.

OBJECTIVE

To characterize ex vivo uptake of common antioxidant topicals after pretreatment with a nonablative laser wavelength.

MATERIALS AND METHODS

Using donor human skin tissue, uptake of 3 topical antioxidants was analyzed (C E Ferulic with 15% l-ascorbic acid [15% vitamin C serum], Phloretin CF with ferulic acid [10% vitamin C serum], and Phyto+ [botanical serum]; SkinCeuticals, Dallas, TX; 2010 formulations) after pretreatment with a 1,440-nm nonablative fractional diode laser.

RESULTS

Pretreatment with the 1,440-nm laser enhanced uptake of 15% and 10% vitamin C serums by approximately 10 and 21 times, respectively, compared to controls. Laser pretreatment also enhanced uptake of botanical serum by approximately 6 times relative to controls. Permeation of vitamin C and botanical serums was also enhanced through laser pretreatment.

CONCLUSION

Nonablative laser pretreatment increased uptake and permeation of topical antioxidants. Optimizing treatment requires consideration of the device and treatment parameters as well as the properties of the topical formulation.

Key Parameters of Non-ablative Fractional Laser Pretreatments for Enhanced Topical Uptake

BACKGROUND

The uptake of topical formulations can be enhanced through laser pretreatments. Newer technologies, such as non-ablative fractional lasers (NAFLs), can target dermal tissues and spare the stratum corneum (SC), which can mitigate common side effects associated with ablative laser treatment.

OBJECTIVE

To discuss parameters of 2 NAFL pretreatment systems (1440-nm/1927-nm diode system or 1550-nm erbium-doped glass/1927-nm thulium system), which can be paired with topicals to improve their cutaneous uptake.

METHODS & MATERIALS

The parameters of the 1440-nm/1927-nm diode system and 1550-nm erbium-doped glass/1927-nm thulium system were reviewed, as well as in-vivo experiments using both laser systems.

RESULTS

Multiple parameters should be optimized to enhance the uptake of various topical formulations and minimize side effects, including wavelength, spot size, density, pulse duration, thermal properties, and topical formulation. Chosen therapeutic parameters must account for patient-specific factors, such as treatment indication, therapeutic area, and Fitzpatrick skin type. In-vivo experiments have demonstrated that both laser systems are effective in enhancing the uptake of various topical therapies relative to untreated controls.

CONCLUSION

Individualization of laser system parameters increases efficiency and minimizes risk.

Quantifying Skin Uptake of Topicals After 1,927-nm and 1,440-nm Nonablative Fractional Diode Laser Treatment

BACKGROUND

Although the stratum corneum limits transdermal absorption of topicals, laser devices can enhance topical uptake by disrupting the skin barrier. Nonablative lasers are commonly used, but their effects on topical uptake should be quantified to optimize outcomes.

OBJECTIVE

The objective of this study is to analyze transdermal uptake of 4 topicals after nonablative fractional diode laser pretreatment.

METHODS AND MATERIALS

Human donor tissue was pretreated ex vivo with a nonablative fractional diode laser (1,927 nm or 1,440 nm, at varying treatment densities, powers, and peak energies) followed by application of either 2% salicylic acid, 10% ascorbic acid, over-the-counter mineral eye serum, or 4% hydroquinone. Topical uptake was quantified over 24 hours.

RESULTS

Despite lower power settings, pretreatment with the 1,927 nm wavelength was associated with greater uptake of 10% ascorbic acid, mineral eye serum, and 4% hydroquinone than the 1,440 nm wavelength. In addition, 1,440-nm laser pretreatment with higher density (320 microscopic treatment zones [MTZ]/cm2) and peak power (3 W) was associated with similar uptake but greater retention of 2% salicylic acid and greater uptake of 10% ascorbic acid than that with lower density (80 MTZ/cm2) and peak power (1.2 W).

CONCLUSION

When using laser pretreatment, device settings should be adjusted to balance outcomes with potential side effects.

Observation on the efficacy of 1565-nm non-ablative fractional laser combined with compound betamethasone topical application on the treatment of early scar in Chinese patients

The objective of the study was to evaluate the efficacy of combining 1565-nm non-ablative fractional laser with low-dose compound betamethasone topical application in the treatment of immature early red hypertrophic scar. We enrolled 38 cases of patients who had immature red hypertrophic scar due to surgery or trauma which are all less than 6 months old. About 28 patients were assigned to the treatment group, and 10 patients were assigned to the control group. The patients in the treatment group were all treated with 1565-nm non-ablative fractional laser with the following parameters: spot size 10-16 mm, round or square-shaped according to lesional morphology, fluence 20-35 mJ/cm², and density 150-200 microspot/cm². The treated area was then applied immediately with low-dose compound betamethasone through topical application. Treatment cycles were repeated every month for a total 5 months. Photos were taken before the start of the treatment, and then monthly after. Vancouver Scar Scale score was used to evaluate the scar changes; all the patients were followed up for 3 more months after the last treatment. All side effects were documented. The patients in the control group received no treatment at all. All the parameters were recorded as the same as the treatment group. The total VSS score after the combination therapy is 0.96 ± 1.53, which in comparison with prior treatment VSS score 8.86 ± 1.43, showed a significant reduction following the treatments (P < 0.001). The control group without any treatment shows VSS score 7.10 ± 0.99 at the end of the study vs VSS score 7.70 ± 0.82 at the start of the study (P > 0.05). The patient satisfaction rate reaches 89.2% after treatment, The major side effects reported include 3 patients with post-inflammatory hyperpigmentation (10.7% of patients in the treatment group), and other minor discomfort such as transient warmth, erythema, and swelling of treatment sites. The combination approach using 1565-nm non-ablative laser and low dose of local application of compound betamethasone can effectively improve the immature red hypertrophic scar with no significant side effects; this should provide our practitioners with a new weapon in fighting those hard-to-manage early scar formations.

Development and evaluation of a heparin gel for transdermal delivery via laser-generated micropores

Aim: Our study investigated the feasibility of transdermal delivery of heparin, an anticoagulant used against venous thromboembolism, as an alternative to intravenous administration. Materials & methods: Skin was pretreated using ablative laser (Precise Laser Epidermal System [P.L.E.A.S.E.^®] technology) for enhanced delivery of heparin. In vitro permeation studies using static Franz diffusion cells provided a comparison between delivery from 0.3% w/v heparin-loaded poloxamer gel and solution across untreated and laser-treated dermatomed porcine ear skin. Results: No passive delivery of heparin was observed. Laser-assisted delivery from solution (26.07 ± 1.82 μg/cm²) was higher (p < 0.05) than delivery from heparin gel (11.28 ± 5.32 μg/cm²). However, gel is likely to sustain the delivery over prolonged periods like a maintenance dose via continuous intravenous infusion. Conclusion: Thus, ablative laser pretreatment successfully delivered heparin, establishing the feasibility of delivering hydrophilic macromolecules using the transdermal route.

Laser-assisted skin delivery of immunocontraceptive rabies nanoparticulate vaccine in poloxamer gel

A painless skin delivery of vaccine for disease prevention is of great advantage in improving compliance in patients. To test this idea as a proof of concept, we utilized a pDNA vaccine construct, pDNAg333-2GnRH that has a dual function of controlling rabies and inducing immunocontraception in animals. The pDNA was administered to mice in a nanoparticulate form delivered through the skin using the P.L.E.A.S.E.® (Precise Laser Epidermal System) microporation laser device. Laser application was well tolerated, and mild skin reaction was healed completely in 8 days. We demonstrated that adjuvanted nanoparticulate pDNA vaccine significantly upregulated the expression of co-stimulatory molecules in dendritic cells. After topical administration of the adjuvanted nano-vaccine in mice, the high avidity serum for GnRH antibodies were induced and maintained up to 9 weeks. The induced immune response was of a mixed Th1/Th2 profile as measured by IgG subclasses (IgG2a and IgG1) and cytokine levels (IFN-γ and IL-4). Using flow cytometry, we revealed an increase of CD8+ T-cells and CD45R B cells upon the administration of the adjuvanted vaccine. Our previous study used the same pDNA nanoparticulate vaccine through an IM route, and a comparable immune response was induced using P.L.E.A.S.E. However, the vaccine dose in the current study was four-fold less than what was applied through the IM route.We concluded that laser-assisted skin vaccination has a potential of becoming a safe and reliable vaccination tool for rabies vaccination in animals or even in humans for pre- or post-exposure prophylaxis.

Transdermal delivery of human growth hormone via laser-generated micropores

The epidermal skin barrier plays an important role in protecting underlying structures. It allows the passage of low molecular weight lipophilic molecules, but restricts the passage of hydrophilic molecules and macromolecules. The objective of this study was to investigate the feasibility of transdermal delivery of human growth hormone (hGH) through laser-microporated dermatomed porcine ear skin. The permeation of hGH was evaluated at different laser fluences and micropore densities. In vitro permeation studies were performed on vertical Franz diffusion cells using dermatomed porcine ear skin treated with ablative laser (2940 nm; P.L.E.A.S.E®, Pantec Biosolutions AG). The effect of different fluences (34.1, 45.4, and 68.1 J/cm²) at 10% pore density as well as different densities of micropores (5, 10, and 15%) at fluence of 34.1 J/cm², on the permeation of hGH was evaluated. After 48 h, 77.12 ± 10.77 μg/cm² hGH was delivered into the receptor with the application of fluence of 45.4 J/cm², which was significantly higher than that observed from 34.1 J/cm² group (53.13 ± 1.75 μg/cm², p < 0.05). Application of fluence of 68.1 J/cm² showed permeation of 90.94 ± 3.93 μg/cm² that was significantly higher than that from 34.1 J/cm² group (p < 0.05), but not as compared to the 45.4 J/cm² group (p > 0.05). With the increase in density of micropores from 5 to 15%, permeation of hGH increased significantly from 7.1 ± 2.63 μg/cm² to 95.89 ± 13.43 μg/cm² after 48 h (p < 0.05). Thus, overall, the variations in the fluence as well as micropore density of the laser were observed to influence hGH permeation, through laser-microporated dermatomed porcine skin.

Is the Fractional Laser Still Effective in Assisting Cutaneous Macromolecule Delivery in Barrier-Deficient Skin? Psoriasis and Atopic Dermatitis as the Disease Models

PURPOSE

Most of the investigations into laser-assisted skin permeation have used the intact skin as the permeation barrier. Whether the laser is effective in improving cutaneous delivery via barrier-defective skin is still unclear.

METHODS

In this study, ablative (Er:YAG) and non-ablative (Er:glass) lasers were examined for the penetration of peptide and siRNA upon topical application on in vitro skin with a healthy or disrupted barrier.

RESULTS

An enhanced peptide flux (6.9 fold) was detected after tape stripping of the pig stratum corneum (SC). A further increase of flux to 11.7 fold was obtained after Er:YAG laser irradiation of the SC-stripped skin. However, the application of Er:glass modality did not further raise the flux via the SC-stripped skin. A similar trend was observed in the case of psoriasiform skin. Conversely, the flux was enhanced 3.7 and 2.6 fold after treatment with the Er:YAG and the Er:glass laser on the atopic dermatitis (AD)-like skin. The 3-D skin structure captured by confocal microscopy proved the distribution of peptide and siRNA through the microchannels and into the surrounding tissue.

CONCLUSIONS

The fractional laser was valid for ameliorating macromolecule permeation into barrier-disrupted skin although the enhancement level was lower than that of normal skin.