Terpene-containing PEGylated liposomes as transdermal carriers of a hydrophilic compound

Unveiling Trends: Nanoscale Materials Shaping Emerging Biomedical Applications

The realm of biomedical materials continues to evolve rapidly, driven by innovative research across interdisciplinary domains. Leveraging big data from the CAS Content Collection, this study employs quantitative analysis through natural language processing (NLP) to identify six emerging areas within nanoscale materials for biomedical applications. These areas encompass self-healing, bioelectronic, programmable, lipid-based, protein-based, and antibacterial materials. Our Nano Focus delves into the multifaceted utilization of nanoscale materials in these domains, spanning from augmenting physical and electronic properties for interfacing with human tissue to facilitating intricate functionalities like programmable drug delivery.

Navigating Skin Delivery Horizon: An Innovative Approach in Pioneering Surface Modification of Ultradeformable Vesicles

In the dynamic landscape of pharmaceutical advancements, the strategic application of active pharmaceutical ingredients to the skin through topical and transdermal routes has emerged as a compelling avenue for therapeutic interventions. This non-invasive approach has garnered considerable attention in recent decades, with numerous attempts yielding approaches and demonstrating substantial clinical potential. However, the formidable barrier function of the skin, mainly the confinement of drugs on the upper layers of the stratum corneum, poses a substantial hurdle, impeding successful drug delivery via this route. Ultradeformable vesicles/carriers (UDVs), positioned within the expansive realm of nanomedicine, have emerged as a promising tool for developing advanced dermal and transdermal therapies. The current review focuses on improving the passive dermal and transdermal targeting capacity by integrating functionalization groups by strategic surface modification of drug-loaded UDV nanocarriers. The present review discusses the details of case studies of different surface-modified UDVs with their bonding strategies and covers the recent patents and clinical trials. The design of surface modifications holds promise for overcoming existing challenges in drug delivery by marking a significant leap forward in the field of pharmaceutical sciences.

A comprehensive review on recent nanosystems for enhancing antifungal activity of fenticonazole nitrate from different routes of administration

This review aims to comprehensively highlight the recent nanosystems enclosing Fenticonazole nitrate (FTN) and to compare between them regarding preparation techniques, studied factors and responses. Moreover, the optimum formulae were compared in terms of in vitro, ex vivo and in vivo studies in order to detect the best formula. FTN is a potent antifungal imidazole compound that had been used for treatment of many dangerous fungal infections affecting eye, skin or vagina. FTN had been incorporated in various innovative nanosystems in the recent years in order to achieve significant recovery such as olaminosomes, novasomes, cerosomes, terpesomes and trans-novasomes. These nanosystems were formulated by various techniques (ethanol injection or thin film hydration) utilizing different statistical designs (Box-Behnken, central composite, full factorial and D-optimal). Different factors were studied in each nanosystem regarding its composition as surfactant concentrations, surfactant type, amount of oleic acid, cholesterol, oleylamine, ceramide, sodium deoxycholate, terpene concentration and ethanol concentration. Numerous responses were studied such as percent entrapment efficiency (EE%), particle size (PS), poly-dispersity index (PDI), zeta potential (ZP), and in vitro drug release. Selection of the optimum formula was based on numerical optimization accomplished by Design-Expert® software taking in consideration the largest EE %, ZP (as absolute value) and in vitro drug release and lowest PS and PDI. In vitro comparisons were done employing different techniques such as Transmission electron microscopy, pH determination, effect of gamma sterilization, elasticity evaluation and docking study. In addition to, ex vivo permeation, in vivo irritancy test, histopathological, antifungal activity and Kinetic study.

Ultra-deformable free fatty acid based nano-carriers for topical delivery of Luteolin: A potential paradigm for management of Methicillin-Resistant Staphylococcus aureus skin infections

The incidences of antimicrobial resistance in particular, Methicillin-Resistant Staphylococcus aureus (MRSA) have increased during the last two decades. However, conventional dosage forms are unable to evade the barrier effect of the stratum corneum to permit deep penetration of the skin to resolve deep skin infections. There is, therefore, an urgent need for an advanced drug delivery system. Thus the study reported herein was aimed to fabricate a novasome-loaded luteolin (LUT) to improve its topical delivery and to enhance its antibacterial activity. The system was investigated for the impact of the type of surfactant, stearic acid concentration (g %), cholesterol amount (mg) and Brij 52 amount (mg) on the percent entrapment efficiency, particle size, poly-dispersity index and zeta potential. Statistical optimization of these factors was conducted using the Design-Expert® software. The optimum formulation was further in-vitro characterized by release study, differential scanning calorimetry, transmission electron microscope, x-ray diffraction and antibacterial activity. Formulation F2 composed of Span 60, 0.4 g % of stearic acid, 100 mg cholesterol and 30 mg Brij 52 was selected as the optimum formula based on the highest desirability value (0.634). F2 demonstrated enhanced antimicrobial activity with lower minimum inhibitory concentrations against a panel of MRSA clinical isolates when compared to LUT dispersion. Furthermore, the F2 formula exhibited higher anti-virulence activity by effectively inhibiting biofilm formation and suppressing α-hemolysin activity in MRSA isolates. It also demonstrated improved biosafety based on cytotoxicity assessment on human skin fibroblasts (HSF). Finally, when assessed in an in vivo skin infection mouse model, the F2 formula and commercially available fusidic acid preparation significantly reduced the microbial load of infected skin lesions compared to both the negative control and LUT dispersion-treated groups. Based on the aforementioned results, the validity of novasomes as a nano-carrier to boost in vitro and in vivo anti-MRSA activity of LUT could be affirmed.

Effect of water content on stratum corneum penetration mechanism of W/O type microemulsions

The stratum corneum (SC) consists of a lipid layer that forms two types of lamellar structures: short lamellar (S-La) and long lamellar (L-La). It has been reported that S-La contains water phases in the hydrophilic region of the lipids, and that it may play an important role in regulating the water content of the SC. The amount of water in the SC can affect how a drug carrier permeates through the intercellular lipid pathway. To better understand the impact of SC water content on the skin penetration mechanism of a microemulsion (ME), we conducted a study using small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and small-angle neutron scattering (SANS). Our results showed that MEs can enhance skin permeation under humid conditions because the lipid packing structures of the hydrated SC are more disrupted than those of the dry SC. The results also showed that the inner water of MEs was released to the SC when applying MEs to the dry SC, resulting in an increase in the repeat distance of S-La. Conversely, when MEs are applied to hydrated SC, the MEs absorb the water from the SC into their inner phases, causing a decrease in the repeat distance of S-La over time.

Brij® integrated bilosomes for improving the transdermal delivery of niflumic acid for effective treatment of osteoarthritis: In vitro characterization, ex vivo permeability assessment, and in vivo study

Bilosomes are innovative vesicular carriers containing bile salt with a non-ionic surfactant. Being highly flexible, bilosomes can squeeze themselves through the skin carrying the drug to the action site and improving its skin penetration. The objective of this research was to encapsulate niflumic acid (NA), a non-steroidal anti-inflammatory drug into Brij® integrated bilosomes (BIBs) for effective treatment of osteoarthritis through transdermal delivery. BIBs were formulated using 100 mg of Span 20 with different amounts of sodium cholate (NaC), sodium taurocholate (NaTC), or sodium glycocholate (NaGC) as bile salt, with the addition of 5 mg of Brij-93 or Brij-35. BIBs were prepared utilizing ethanol injection method with the application of (3¹×2²) complete factorial design using Design-Expert® software. The optimal BIBs formulation determined was (B5) which contains 5 mg of NaTC used as bile salt and 5 mg of Brij-93. B5 exhibited entrapment efficiency% = 95.21 ± 0.00%, particle size = 373.05 ± 0.07 nm, polydispersity index = 0.27 ± 0.01, and zeta potential = -32.00 ± 0.00 mV. It also had a high elasticity with a spherical shape. B5 gel displayed a sustained release profile with a significantly 2.3 folds' higher drug permeation percent across rat skin than that permeated from NA gel. Moreover, in vivo anti-osteoarthritic and histopathological studies assured the efficacy and safety of B5 gel and its superiority over NA gel. Generally, the outcomes confirmed the great efficacy of NA loaded BIBs for the topical treatment of osteoarthritis.

Effect of zeta potential of innovative lipid nanocapsules on triamcinolone transdermal delivery

Two pegylated lipid nanocapsules for triamcinolone transdermal delivery were designed. Both present a size close to 50 nm and a single monomodal distribution in particle size (PI < 0.2), with a zeta potential of - 20 ± 2 and + 18 ± 1, respectively. The triamcinolone encapsulation efficacy varied between 68 and 80%. They proved to be stable under storage conditions (4 °C) for at least 6 months and at a physiological temperature, using different media, for 48 h. Also, they were shown not to affect cell viability at the concentrations used. For ex vivo transdermal experiments, newborn pig skin was used. With respect to the triamcinolone transdermal penetration, the nanocapsules were demonstrated to have an absorption promoting effect, both when the drug nanocapsules were in solution or loaded into the hydrogel, quantifying between 2 and 15 times more absorbed drug than the control. In addition, regarding the triamcinolone retained in the skin, it is observed that lipid nanocapsules act as triamcinolone promoters when the nanosystems were in solution and when they were included in the hydrogel. This vehicle showed a greater triamcinolone reservoir effect in comparison to the nanocapsules, proving to be a good vehicle to formulate triamcinolone transdermal delivery.

Ex vivo transtympanic permeation of the liposome encapsulated S. pneumoniae endolysin MSlys

An increase in bacterial resistance to systemic antibiotics has sparked interest into alternative antimicrobial compounds as well as methods for effective local, non-invasive drug delivery. Topical treatments, however, may be hindered by the presence of biological barriers, such as the tympanic membrane in the case of otitis media. Herein, the transtympanic permeation ability of liposomes loaded with the pneumococcal endolysin MSlys and of free MSlys was evaluated ex vivo. MSlys loaded in PEGylated liposomes showed an increased permeation across human tympanic membranes, as compared to its free form, being able to reduce the pneumococcal cell load after 2 h of permeation. However, antipneumococcal activity was no longer detected after 4 h of permeation and hydrolysis of the endolysin was observed after an extended incubation time (≥48 h). This work provides a first assessment of a successful, non-invasive delivery method for endolysins across an intact tympanic membrane. Findings have implications for non-systemic, local treatment of otitis media.

Fenticonazole nitrate loaded trans-novasomes for effective management of tinea corporis: design characterization, in silico study, and exploratory clinical appraisal

The current investigation aimed for loading fenticonazole nitrate (FTN), an antifungal agent with low aqueous solubility, into trans-novasomes (TNs) for management of tinea corporis topically. TNs contain Brij^® as an edge activator besides the components of novasomes (cholesterol, Span 60, and oleic acid) owing to augment the topical delivery of FTN. TNs were fabricated applying ethanol injection method based on D-optimal experiment. TNs were evaluated with regard to entrapment efficiency percent (EE%), particle size (PS), polydispersity index (PDI), and zeta potential (ZP). Further explorations were conducted on the optimum formulation (F7). F7 showed spherical appearance with EE%, PS, PDI, and ZP of 100.00 ± 1.10%, 358.60 ± 10.76 nm, 0.51 ± 0.004, and −30.00 ± 0.80 mV, respectively. The in silico study revealed the ability of the FTN–cholesterol complex to maintain favorable interactions throughout the molecular dynamics simulation (MDS) study. Moreover, Trichophyton mentagrophytes growth was inhibited effectively by F7 than by FTN suspension applying 2,3-bis(2-methyloxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. Furthermore, a clinical appraisal on patients with tinea corporis fungal lesions confirmed the superiority of F7 compared to Miconaz^® cream in the magnitude of clinical cure of tinea corporis. Thereby, TNs could be considered as promising vesicles for enhancing the antifungal potential of FTN for the topical management of tinea corporis.

Tetrahydrocurcumin Lipid Nanoparticle Based Gel Promotes Penetration into Deeper Skin Layers and Alleviates Atopic Dermatitis in 2,4-Dinitrochlorobenzene (DNCB) Mouse Model

Treatment of atopic dermatitis (AD) is challenging due to its complex pathophysiology. Tetrahydrocurcumin (THC) a polyphenolic, colorless compound that is more polar than curcumin. It possesses superior anti-inflammatory properties and has a clinical advantage over curcumin. The present study investigated the therapeutic effectiveness of THC solid lipid nanoparticle (THC-SLN)-based gels in AD. THC-SLNs prepared using microemulsification resulted in a particle size of 109.2 nm as determined by nanoparticle tracking, and FTIR confirmed the entrapment of drug within the lipid matrix. THC-SLNs greatly enhanced skin hydration when tested both ex vivo and in vivo in Lacca mice. Deeper skin penetration was clearly established using dermatokinetics and CLSM. The in vivo pharmacodynamics of THC-SLNs gel in 2,4-dinitrochlorobenzene (DNCB)-induced AD mice showed enhanced bioactivity; reduced levels of TNF-α and IL-6; and complete healing, as evident from histopathological studies. Thus, the novel topical THC-SLN gel has potential to emerge as a safe alternative to conventional corticosteroids for AD and other skin disorders with overbearing inflammation.

Utilization of PEGylated cerosomes for effective topical delivery of fenticonazole nitrate: in-vitro characterization, statistical optimization, and in-vivo assessment

In this investigation, we focused on ceramide IIIB, a skin component whose depletion tends to augment multiple skin disorders and fungal infections. Ceramide IIIB was included into PEGylated surfactant-based vesicular phospholipid system to formulate 'PEGylated cerosomes' (PCs) loaded with fenticonazole nitrate (FTN). FTN is a potent antifungal agent adopted in the treatment of mixed mycotic and bacterial infections. The ceramide content of the vesicles may provide protective and regenerative skin activity whereas Brij®; the PEGylated surfactant, can enhance drug deposition and skin hydration. Both components are expected to augment the topical effect of FTN. PCs were prepared by thin-film hydration technique. A 23 full-factorial design was applied to study the effect of ceramide amount (X1), Brij type (X2) and Brij amount (X3) on the physicochemical properties of the formulated PCs namely; entrapment efficiency (EE%;Y1), particle size (PS;Y2), polydispersity index (PDI;Y3) and zeta potential (ZP;Y4). The optimal formula was selected for further in-vivo dermatokinetic and histopathological study. The optimal FTN-loaded PC (PC6) showed nanosized cerosomes (551.60 nm) with high EE% (83.00%w/w), and an acceptable ZP value of 20.90 mV. Transmission electron micrographs of the optimal formula illustrated intertwined tubulation form deviated from the conventional spherical vesicles. Finally, the dermatokinetic study of PC6 showed higher drug concentration and localization of FTN in skin layers when compared with FTN suspension and the histopathological study confirmed its safety for topical application. The overall findings of our study verified the effectiveness of utilizing PEGylated cerosomes to augment the activity of FTN as a topical antifungal agent.

The technology of transdermal delivery nanosystems: from design and development to preclinical studies

Transdermal administration has gained much attention due to the remarkable advantages such as patient compliance, drug escape from first-pass elimination, favorable pharmacokinetic profile and prolonged release properties. However, the major limitation of these systems is the limited skin penetration of the stratum corneum, the skin's most important barrier, which protects the body from the insertion of substances from the environment. Transdermal drug delivery systems are aiming to the disruption of the stratum corneum in order for the active pharmaceutical ingredients to enter successfully the circulation. Therefore, nanoparticles are holding a great promise because they can act as effective penetration enhancers due to their small size and other physicochemical properties that will be analyzed thoroughly in this report. Apart from the investigation of the physicochemical parameters, a comparison between the different types of nanoparticles will be performed. The complexity of skin anatomy and the unclear mechanisms of penetration should be taken into consideration to reach some realistic conclusions regarding the way that the described parameters affect the skin permeability. To the best of the authors knowledge, this is among the few reports on the literature describing the technology of transdermal delivery systems and how this technology affects the biological activity.

Development and Optimization of Terpene-Enriched Vesicles (Terpesomes) for Effective Ocular Delivery of Fenticonazole Nitrate: In vitro Characterization and in vivo Assessment

Objective

The aim of the current study was to load fenticonazole nitrate, a slightly water-soluble antifungal agent, into terpene-enriched phospholipid vesicles (terpesomes) as a potential delivery system for the management of ocular fungal infection.

Methods

Thin film hydration method was used to prepare terpesomes according to a 3² full factorial design to inspect the effect of several variables on vesicles’ features. The investigated factors were terpenes type (X₁) and terpenes amount (X₂) while the dependent responses were encapsulation efficiency percent (Y₁), particle size (Y₂) and polydispersity index (Y₃). Design Expert^® program was used to chose the best achieved formula. The selected terpesomes were further optimized via incorporation of a positive charge inducer (stearylamine) to enhance adhesion to the negatively charged mucus covering the eye surface. The in vivo performance of the optimized fenticonazole nitrate-loaded terpesomes relative to drug suspension was evaluated by measuring the antifungal activity (against Candida albicans) retained in the tear's fluid at different time intervals after ocular application in albino rabbits.

Results

The optimized terpesomes showed spherical vesicles with entrapment efficiency of 79.02±2.35%, particle size of 287.25±9.55 nm, polydispersity index of 0.46±0.01 and zeta potential of 36.15±1.06 mV. The in vivo study demonstrated significantly higher ocular retention of the optimized fenticonazole nitrate-loaded terpesomes relative to the drug suspension. Moreover, the histopathological studies proved the safety and biocompatibility of the prepared terpesomes.

Conclusion

The obtained results verified the potential of the terpesomes for safe and effective ocular delivery of fenticonazole nitrate.

SLN and NLC for topical, dermal, and transdermal drug delivery

Introduction: From a biopharmaceutical standpoint, the skin is recognized as an interesting route for drug delivery. In general, small molecules are able to penetrate the stratum corneum, the outermost layer of the skin. In contrast, the delivery of larger molecules, such as peptides and proteins, remains a challenge. Nanoparticles have been exploited not only to enhance skin penetration of drugs but also to expand the range of molecules to be clinically used.Areas covered: This review focus on Solid lipid nanoparticles (SLN) and Nanostructured lipid carriers (NLC) for skin administration. We discuss the selection criteria for lipids, surfactants, and surface modifiers commonly in use in SLN/NLC, their production techniques, and the range of drugs loaded in these lipid nanoparticles for the treatment of skin disorders.Expert opinion: Depending on the lipid and surfactant composition, different nanoparticle morphologies can be generated. Both SLN and NLC are composed of lipids that resemble those of the skin and sebum, which contribute to their enhanced biocompatibility, with limited toxicological risk. SLN and NLC can be loaded with very chemically different drugs, may provide a tunable release profile, can be produced in a sterilized environment, and be scaled-up without the need for organic solvents.

Tailoring of PEGylated bilosomes for promoting the transdermal delivery of olmesartan medoxomil: in-vitro characterization, ex-vivo permeation and in-vivo assessment

Introduction

The intention of this work was to load olmesartan medoxomil (OLM), a sparsely water soluble antihypertensive bioactive with low oral bioavailability (26%), into PEGylated bilosomes (PBs) for augmenting its transdermal delivery. PBs contain PEGylated single chain edge activator besides the components of traditional bilosomes (Span 60, cholesterol and bile salts). The PEG gives further resilience to vesicle membrane and is speculated to augment both permeability and bioavailability of OLM.

Methods

A 2⁴ factorial experiment was constructed to inspect the impact of diverse variables on vesicles’ features and sort out the optimal formula adopting Design Expert^® software utilizing thin film hydration technique. Vesicles’ evaluation was done by finding out entrapment efficiency percent (EE%), particle size (PS), polydispersity index (PDI), zeta potential (ZP) and amount of drug released after 6 hrs (Q6h). The optimal formula was selected and characterized for further investigations.

Results

The optimal formula (PB15) showed spherical vesicles with EE% of 72.49±0.38%, PS of 559.30±10.70 nm, PDI of 0.57±0.15, ZP of −38.35±0.65 mV and Q6h of 59.60±0.24%. PB15 showed higher deformability index (28.39±5.71 g) compared to traditional bilosomes (5.88±0.90 g) and transethosomes (14.94±0.63 g). Further, PB15 showed superior skin permeation from rat’s skin relative to the drug suspension. Moreover, confocal laser scanning microscopy examination revealed efficient penetration of the fluoro-labeled PB15 through skin. Histopathological study ensured the safety of PB15. In addition, in-vivo skin deposition studies showed higher OLM deposition in rat’s skin from PB15 compared to transethosomes and OLM suspension. Furthermore, pharmacodynamic and pharmacokinetic studies performed using male Wistar rats and male Albino rabbits, respectively, showed the superiority of PB15 over oral tablets. PB15 was found to have significantly higher AUC_0–48 and AUC_0–∞ relative to the oral tablets. As well, the relative bioavailability of PB15 was found to be 235.04%.

Conclusion

Overall, the obtained results confirmed the creditable effect of PB15 for transdermal delivery.

Essential Oils and Isolated Terpenes in Nanosystems Designed for Topical Administration: A Review

Essential oils are natural products with a complex composition. Terpenes are the most common class of chemical compounds present in essential oils. Terpenes and the essential oils containing them are widely used and investigated by their pharmacological properties and permeation-enhancing ability. However, many terpenes and essential oils are sensitive to environmental conditions, undergoing volatilization and chemical degradation. In order to overcome the chemical instability of some isolated terpenes and essential oils, the encapsulation of these compounds in nanostructured systems (polymeric, lipidic, or molecular complexes) has been employed. In addition, nanoencapsulation can be of interest for pharmaceutical applications due to its capacity to improve the bioavailability and allow the controlled release of drugs. Topical drug administration is a convenient and non-invasive administration route for both local and systemic drug delivery. The present review focuses on describing the current status of research concerning nanostructured delivery systems containing isolated terpenes and/or essential oils designed for topical administration and on discussing the use of terpenes and essential oils either for their biological activities or as permeation enhancers in pharmaceutic formulations.

Enhancement of Galantamine HBr Skin Permeation Using Sonophoresis and Limonene-Containing PEGylated Liposomes

This study aimed to investigate the effect of low-frequency sonophoresis (SN) and limonene-containing PEGylated liposomes (PL) on the transdermal delivery of galantamine HBr (GLT). To evaluate the skin penetration mechanism, confocal laser scanning microscopy (CLSM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were employed. The application of SN led to more GLT penetration into and through the skin than GLT solution alone. The liposomes also improved GLT permeation, and 2% limonene-containing PL (PL-LI2%) exhibited the highest GLT permeation, followed by PL-LI1%, PL-LI0.1%, and PL. The CLSM images of PL-LI2% resulted in the highest fluorescence intensity of fluorescent hydrophilic molecules in the deep skin layer, and the rhodamine PE-labeled liposome membrane was distributed in the intercellular region of the stratum corneum (SC). PL-LI2% induced significant changes in intercellular lipids in the SC, whereas SN had no effect on intercellular lipids of the SC. DSC thermograms showed that the greatest decrease in the lipid transition temperature occurred in PL-LI2%-treated SC. SN might improve drug permeation through an intracellular pathway, while limonene-containing liposomes play an important role in delivering GLT through an intercellular pathway by increasing the fluidity of intercellular lipids in the SC. Moreover, a small vesicle size and high membrane fluidity might enhance the transportation of intact vesicles through the skin.

Preparation of mixed monoterpenes edge activated PEGylated transfersomes to improve the in vivo transdermal delivery efficiency of sinomenine hydrochloride

Surfactants generally have been used as edge activators of transfersomes. However, surfactants edge activated transfersomes frequently lead to cutaneous irritation, skin lipid loss and other side effects after dermal administration. In this study, mixed monoterpenes edge activated PEGylated transfersomes (MMPTs) were prepared by ethanol injection process with sinomenine hydrochloride as a model drug. The formulation of MMPTs was optimized by an orthogonal design. We investigated skin permeation/deposition characteristics and pharmacokinetics of sinomenine hydrochloride loaded in MMPTs by comparing with liposomes using in vitro skin tests and in vivo cutaneous microdialysis. In in vitro study, the accumulative skin permeated quantity (ASPQ) and skin permeation rate (SPR) of simonenine (SIN) in the optimized MMPTs were prominently higher than that in the other MMPTs. The optimized MMPTs had a SIN ASPQ of over three times of SIN ASPQ in the liposomes and much larger SPR of SIN compared with the latter. In contrast, the drug deposition of the optimized MMPTs in the stratum corneum was much less than that of the conventional liposomes. It was noteworthy that the drug deposition curve in the whole skin (stratum corneum-stripped skin, either) for the optimized MMPTs increased initially and then decreased with an obvious peak deposition amount at 12h, while, a relatively steady curve was observed for the liposomes. In in vivo cutaneous pharmacokinetic study, the steady state concentration (C_ss) and the area under the curve (AUC_0→t) of SIN from the optimized MMPTs was 8.7 and 8.2 folds higher than those from the liposomes, respectively. Moreover, the MRT_0-inf of SIN from optimal MMPTs got shorter than that from the liposomes. It can be concluded that the optimized MMPTs obviously enhance the percutaneous absorption of sinomenine.

Mechanistic study of decreased skin penetration using a combination of sonophoresis with sodium fluorescein-loaded PEGylated liposomes with d-limonene

The effect of low frequency sonophoresis (SN, 20 kHz) on the skin transport of sodium fluorescein (NaFI)-loaded liposomes was investigated. An in vitro skin penetration study in open and blocked hair follicles was performed, and confocal laser scanning microscopy and scanning electron microscopy were used to visualize the penetration pathways. The results showed that SN significantly increased the flux of NaFI solution, whereas it significantly decreased the flux of NaFI-loaded polyethylene glycol-coated (PEGylated) liposomes with D-limonene (PL-LI). SN did not significantly affect the flux of NaFI-loaded conventional liposomes and PEGylated liposomes. In the blocked follicles, the flux of NaFI-loaded PL-LI both with and without SN decreased, indicating that NaFI-loaded PL-LI penetrated the skin via the transfollicular pathway. A confocal laser scanning microscopy image showed that in the skin without SN, the fluorescence intensity of NaFI-loaded PL-LI was observed in the skin and along the length of hair inside the skin, whereas in the skin with applied SN, the fluorescence intensity was detected only on the top of hair outside the skin. From scanning electron microscopy images, SN dislocated the corneocytes and reduced the deposition of PL-LI around hair follicles. These results revealed that SN may partially plug hair follicle orifices and reduce percutaneous absorption through the follicular pathway.