Colon-targeted oral nanoliposomes loaded with psoralen alleviate DSS-induced ulcerative colitis.

Oral administration, while convenient, but complex often faces challenges due to the complexity of the digestive environment. In this study, we developed a nanoliposome (NLP) encapsulating psoralen (P) and coated it with chitosan (CH) and pectin (PT) to formulate PT/CH-P-NLPs. PT/CH-P-NLPs exhibit good biocompatibility, superior to liposomes loaded with psoralen and free psoralen alone. After oral administration, PT/CH-P-NLPs remain stable in the stomach and small intestine, followed by a burst release of psoralen after reaching the slightly alkaline and gut microbiota-rich colon segment. In the DSS-induced ulcerative colitis of mice, PT/CH-P-NLPs showed significant effects on reducing inflammation, mitigating oxidative stress, protecting the integrity of the colon mucosal barrier, and modulating the gut microbiota. In conclusion, the designed nanoliposomes demonstrated the effective application of psoralen in treating ulcerative colitis.

The potassium channel Kv1.3 as a therapeutic target for immunocytoprotection after reperfusion.

OBJECTIVE: The voltage-gated potassium channel Kv1.3, which is expressed on activated, disease-associated microglia and memory T cells, constitutes an attractive target for immunocytoprotection after endovascular thrombectomy (EVT). Using young male mice and rats we previously demonstrated that the Kv1.3 blocker PAP-1 when started 12 h after reperfusion dose-dependently reduces infarction and improves neurological deficit on day 8. However, these proof-of-concept findings are of limited translational value because the majority of strokes occur in patients over 65 and, when considering overall lifetime risk, in females. Here, we therefore tested whether Kv1.3 deletion or delayed pharmacological therapy would be beneficial in females and aged animals. METHODS: Transient middle cerebral artery occlusion (tMCAO, 60 min) was induced in 16-week-old and 80-week-old male and female wild-type C57BL/6J and Kv1.3-/- mice. Stroke outcomes were assessed daily with the 14-score tactile and proprioceptive limp placing test and on day 8 before sacrifice by T2-weighted MRI. Young and old female mice were treated twice daily with 40 mg/kg PAP-1 starting 12 h after reperfusion. Microglia/macrophage activation and T-cell infiltration were evaluated in whole slide scans. RESULTS: Kv1.3 deletion provided no significant benefit in young females but improved outcomes in young males, old males, and old females compared with wild-type controls of the same sex. Delayed PAP-1 treatment improved outcomes in both young and old females. In old females, Kv1.3 deletion and PAP-1 treatment significantly reduced Iba-1 and CD3 staining intensity in the ipsilateral hemisphere. INTERPRETATION: Our preclinical studies using aged and female mice further validate Kv1.3 inhibitors as potential adjunctive treatments for reperfusion therapy in stroke by providing both genetic and pharmacological verification.

CD8+ T cells mediate ultraviolet A-induced immunomodulation in a model of extracorporeal photochemotherapy.

Extracorporeal photochemotherapy (ECP) that takes advantage of the immunomodulatory effects of UV light has been extensively used for many years for the treatment of several T cell-mediated diseases, including graft-versus-host disease (GvHD) and systemic scleroderma. Immune mechanisms that lead to the establishment of T cell tolerance in ECP-treated patients remain poorly known. In this study, we have tested the effect of UV/psoralen-treated BM-derived dendritic cells, referred to as ECP-BMDCs on the outcome of an antigen-specific T cell-mediated reaction, that is, contact hypersensitivity (CHS), which is mediated by CD8+ effector T cells (CD8+ Teff ). The intravenous (i.v.) injection of antigen-pulsed ECP-BMDCs in recipient C57BL/6 mice induced specific CD8+ T cells endowed with immunomodulatory properties (referred to as CD8+ TECP ), which prevented the priming of CD8+ Teff and the development of CHS, independently of conventional CD4+ regulatory T cells. CD8+ TECP mediated tolerance by inhibiting the migration and functions of skin DC and subsequently the priming of CD8+ Teff . CD8+ TECP displayed none of the phenotypes of the usual CD8+ T regulatory cells described so far. Our results reveal an underestimated participation of CD8+ T cells to ECP-induced immunomodulation that could explain the therapeutic effects of ECP in T cell-mediated diseases.

Simultaneous determination of multiple components in rat plasma and pharmacokinetic studies at a pharmacodynamic dose of Xian-Ling-Gu-Bao capsule by UPLC-MS/MS.

Xian-Ling-Gu-Bao capsule (XLGB) is an effective traditional Chinese medicine prescription (TCMP) that is used for the prevention and treatment of osteoporosis in China. A rapid, simple, efficient and stable method based on UPLC-MS/MS technology was developed for simultaneous determination of multiple components of XLGB in rat plasma. Mass spectrometric detection was performed in multiple reaction monitoring (MRM) mode with electrospray ionization (ESI). For twenty-one selected quantitative prototypes, all calibration curves showed favourable linearity (r>0.9932) in linear ranges. The lower limits of quantification (LLOQs) were 2 ng/mL for psoralen (PL), 2.5 ng/mL for asperosaponin VI (AS), 1 ng/mL for isopsoralen (IPS) and sweroside (SW), 0.5 ng/mL for magnoflorine (MA), bavachinin (BVN), tanshinone IIA (TA), timosaponin BII (TBII) and icaritin (ICT), 0.1 ng/mL for epimedin B (EB) and epimedin C (EC), 0.05 ng/mL for icariin (IC), isobavachalcone (IBC), psoralidin (PD), bavachin (BV), bavachalcone (BC), epimedin A (EA) and isobavachin (IBV), 0.02 ng/mL for neobavaisoflavone (NEO) and icariside I (ICI) and 0.01 ng/mL for icariside II (ICII). The intra-day and inter-day (low, medium, high) precision (relative standard deviation) for all analytes was less than 8.63%, and the accuracies (as relative error) were in the range of -12.45% to 8.91%. Extraction recoveries and matrix effects of analytes and IS were acceptable. All analytes were stable during the assay and storage in plasma samples. The validated method was successfully applied to the pharmacokinetics (PK) studies of the twenty-one prototypes at pharmacodynamic doses (0.3 and 1 g/kg/day). In addition, dynamic profiles of 28 metabolites (phase II conjugates: 23 glucuronide conjugates, 2 sulfate conjugates and 3 glucuronide or sulfate conjugates) were also monitored by their area/IS area-time curves. As a result, coumarins, prenylated flavonoids from Psoraleae Fructus, alkaloids and prenylated flavonol glycosides from Epimedii Herba, and iridoid glycosides, triterpenoid saponins from Dipsaci Asperoidis Radix were considered to be the key effective substances of XLGB due to their high exposure and appropriate pharmacokinetic features. This is the first report to reveal pharmacodynamic ingredients by a reversed pharmacodynamic (PD) - pharmacokinetics (PK) study.

To determine irradiance of ultraviolet A in ambient sunlight and optimum exposure time for PUVAsol in a North Indian location.

BACKGROUND: Psoralen with ultraviolet A is an effective photochemotherapeutic modality. A subtype of this, PUVAsol, uses sunlight as the natural source of ultraviolet A. The amount of sunlight received and the consequent ultraviolet A exposure vary according to the month in the year, time of the day and geographical location of a place. AIM: The aim of this study is to determine irradiance of ultraviolet A in ambient sunlight and optimum exposure time for PUVAsol. MATERIALS AND METHODS: This was an observational study carried out at Postgraduate Institute of Medical Education and Research, Chandigarh (30.7333°N, 76.7794°E), India using a photometer. Ultraviolet A irradiance was recorded at a fixed place at 10 AM, once weekly for a period of 12 months. RESULTS: The irradiance of peak ultraviolet A was found to be 3.1 mW/cm2 in June 2016 while irradiance of 0.64 mW/cm2 was recorded in January 2017. The exposure time needed for therapeutic dose of 2 J/cm2 was 11 min 6 s in June 2016 while exposure time for achieving therapeutic dose of 2 J/cm2 was 52 min 5 s in January 2017. The duration of exposure was found to be significantly longer in the winter months. LIMITATION: The limitation of the study is not determining ultraviolet B radiation and infrared exposure. Other limitation of this study is that the irradiance was measured only at 10 am. This data cannot be used to determine irradiance at different time points in the day as the patient may expose himself/herself to sunlight anytime depending on his/her convenience. CONCLUSIONS: The study demonstrates the mean exposure time required for a given therapeutic dose of ultraviolet A in different months. The wide variation in ultraviolet A irradiance in natural sunlight over the year in different months also suggests that exposure times for PUVAsol should be based on the season and geographical location at the site of therapy and not based on uniform guidelines.

Folliculotropic mycosis fungoides in a pediatric patient with response to psoralen-ultraviolet A phototherapy.

Mycosis Fungoides is the most common cutaneous T-cell lymphoma however, it is rare in children. We present the case of a Folliculotropic Mycosis Fungoides in a 13-year-old boy which initially presented as a plaque on his face and was treated with local PUVA therapy. Afterwards the lesions spread so the treatment was changed to systemic PUVA with good response. Although the experience in the treatment of Mycosis Fungoides in pediatric patients is limited, PUVA therapy seems to be an effective and safe option.

The role of long-wavelength ultraviolet A1 (UVA1) in acral vitiligo.

INTRODUCTION: Acral vitiligo is a resistant subtype of vitiligo that does not respond easily to any treatment modality. Ultraviolet A1 (UVA1) (340-400 nm) therapy can penetrate the deep dermis of the skin and is relatively free of adverse effects associated with different phototherapeutic modalities. This study's objective was to evaluate the effect of medium-dose long-wavelength UVA1 (40-70 J) in acral vitiligo treatment and compare it with topical psoralen plus ultraviolet A (topical PUVA). METHODS: Patients in this randomized-controlled comparative clinical trial were divided into two groups, medium-dose UVA1 group and topical PUVA group (10 acral vitiligo patients each). Patients received 36 sessions of phototherapy over a period of 12 weeks. Every patient was clinically evaluated monthly as regards the appearance of new lesions or increase in diameter of the current lesion according to point counting and vitiligo area severity index. RESULTS: No statistically significant clinical difference was found between patients in UVA1 and topical PUVA groups regarding response and pattern of response (P > 0.05). CONCLUSION: Ultraviolet A1 seems to be of limited use as a monotherapy in acral vitiligo treatment. However, more studies combining it with other treatment modalities as systemic steroids and/or using higher UVA1 doses may prove beneficial.

A non-inferiority randomized controlled clinical trial comparing Unani formulation & psoralen plus ultraviolet A sol in chronic plaque psoriasis.

BACKGROUND & OBJECTIVES: Though Unani medications have been used for centuries to treat psoriasis, there is paucity of published studies which have systematically evaluated their efficacy and safety. This study was conducted to establish non-inferiority of Unani medications (oral UNIM-401 and topical UNIM-403) vs psoralen plus ultraviolet A (PUVA) sol in treatment of moderate-severe chronic plaque psoriasis (CPP) in achieving psoriasis area severity index (PASI) 75 at 12 wk and to estimate proportion of patients who relapsed in follow up period of 12 weeks, after having achieved PASI 50. METHODS: In this randomized, controlled trial patients with CPP were block randomized to receive either Unani treatment (147 patients) or PUVA sol (140 patients) for 12 weeks. Percentage reduction in PASI was determined in each patient at 12 wk to calculate number of patients who achieved PASI 75 as also to estimate median of percentage reduction in PASI in each group. All patients who achieved PASI 50 at 12 weeks were followed up for another 12 wk to determine proportion of patients who relapsed. RESULTS: Of the 287 patients randomized, 84 of 147 in Unani group and 67 of 140 in PUVA sol group completed 12 weeks of treatment. On intention-to-treat (ITT) analysis, the response in patients on Unani medication was not inferior to those receiving PUVA sol, in attaining PASI 75 (16.3% in Unani group vs 15.7% in the PUVA sol group). Median of percentage reduction of PASI at 12 wk from baseline in Unani group (68.2%; -60, 100) and PUVA sol group (63%; -15.7, 100) was comparable. Proportion of patients who relapsed at 24 wk was comparable in both groups. However, frequency of clinical side effects was significantly higher (P =0.001) in PUVA sol group (16.4%) compared to Unani group (2%). INTERPRETATION & CONCLUSIONS: The findings of the present study indicated that oral UNIM-401 and topical UNIM-403 were effective and well tolerated therapeutic options in patients with moderate-severe CPP.

An observer-blinded randomized controlled pilot trial comparing localized immersion psoralen-ultraviolet A with localized narrowband ultraviolet B for the treatment of palmar hand eczema.

BACKGROUND: Hand eczema is a common inflammatory dermatosis that causes significant patient morbidity. Previous studies comparing psoralen-ultraviolet A (PUVA) with narrowband ultraviolet B (NB-UVB) have been small, nonrandomized and retrospective. OBJECTIVES: To conduct an observer-blinded randomized controlled pilot study using validated scoring criteria to compare immersion PUVA with NB-UVB for the treatment of chronic hand eczema unresponsive to topical steroids. METHODS: Sixty patients with hand eczema unresponsive to clobetasol propionate 0·05% were randomized to receive either immersion PUVA or NB-UVB twice weekly for 12 weeks with assessments at intervals of 4 weeks. The primary outcome measure was the proportion of patients achieving 'clear' or 'almost clear' Physician's Global Assessment (PGA) response at 12 weeks. Secondary outcome measures included assessment of the modified Total Lesion and Symptom Score (mTLSS) and the Dermatology Life Quality index (DLQI). RESULTS: In both treatment arms, 23 patients completed the 12-week assessment for the primary outcome measure. In the PUVA group, five patients achieved 'clear' and eight 'almost clear' [intention-to-treat (ITT) response rate 43%]. In the NB-UVB group, two achieved 'clear' and five 'almost clear' (ITT response rate 23%). For the secondary outcomes, median mTLSS scores were similar between groups at baseline (PUVA 9·5, NB-UVB 9) and at 12 weeks (PUVA 3, NB-UVB 4). Changes in DLQI were similar, with improvements in both groups. CONCLUSIONS: In this randomized pilot trial recruitment was challenging. After randomization, there were acceptable levels of compliance and safety in each treatment schedule, but lower levels of retention. Using validated scoring systems - PGA, mTLSS and DLQI - as measures of treatment response, the trial demonstrated that both PUVA and NB-UVB reduced the severity of chronic palmar hand eczema.

Psoralen Inhibited Apoptosis of Osteoporotic Osteoblasts by Modulating IRE1-ASK1-JNK Pathway.

Osteoporosis is a common disease causing fracture in older populations. Abnormal apoptosis of osteoblasts contributes to the genesis of osteoporosis. Inhibiting apoptosis of osteoblasts provides a promising strategy to prevent osteoporosis. The proliferation of osteoblasts isolated from osteoporotic patients or healthy subjects was determined by MTT assay. Apoptosis was determined by Annexin V/PI assay. Protein expression was measured by western blot. The proliferation of osteoblasts isolated from osteoporotic patients was inhibited and the apoptosis level of these cells was higher than the osteoblasts from healthy subjects. Incubation with psoralen or estradiol significantly enhanced the proliferation and decreased the apoptosis level of osteoporotic osteoblasts. Western blot demonstrated that psoralen or estradiol treatment downregulated the expression of IRE1, p-ASK, p-JNK, and Bax. Meanwhile, expression of Bcl-2 was upregulated. Pretreatment by IRE1 agonist tunicamycin or JNK agonist anisomycin attenuated the effect of psoralen on osteoporotic osteoblasts. Psoralen inhibited apoptosis of osteoporotic osteoblasts by regulating IRE1-ASK1-JNK pathway.

Psoralen loaded liposomal nanocarriers for improved skin penetration and efficacy of topical PUVA in psoriasis.

Psoralen in combination with ultraviolet A radiation (PUVA) is an FDA recommended therapy for clinical application in the management of severe recalcitrant psoriasis. Psoralen acts by intercalation of DNA and upon exposure to UV-A, it forms monoadducts which in turn induce apoptosis. Poor skin deposition, weak percutaneous permeability of psoralen and adverse effects of severe burning, blisters, pigmentation associated with conventional topical psoralen vehicles hinders the therapeutic efficacy and safety of topical PUVA. The aim of the present study is to formulate psoralen loaded liposomal nanocarriers for enhanced skin penetration, safety and efficacy of topical PUVA in psoriasis. Two different liposomal compositions i.e., cationic liposomes composed of DC-Chol, cholesterol and anionic liposomes composed of egg lecithin, cholesterol, tetramyristoyl cardiolipin were prepared for the topical delivery of psoralen. Liposomal carriers were characterized with respect to size, zeta potential, entrapment efficiency, stability, in vitro drug release and in vivo studies. Both liposomes were prepared with particle size of nearly 100nm. Zeta potential and entrapment efficiency of cationic liposomes were +25.8mV, 75.12% and anionic liposomes were -28.5mV, 60.08% respectively. Liposomal dermal distribution demonstrated higher penetration of both liposomal carriers over solution. Similarly, skin permeation study indicated 5 fold increase in permeation of psoralen with liposomal carriers. Topical application of psoralen liposomal gels on imiquimod induced psoriatic plaque model reduced the symptoms of psoriasis and levels of key psoriatic cytokines such as tumor necrosis factor-α, IL-17 and IL-22. In conclusion, the developed liposomal carriers of psoralen were found to be promising and can find application for optimal safety and efficacy of topical PUVA in psoriasis.

Hydrogel-thickened nanoemulsions based on essential oils for topical delivery of psoralen: Permeation and stability studies.

Nanoemulsions (NE) have attracted much attention due to their as dermal delivery systems for lipophilic drugs such as psoralens. However, NE feature low viscosity which might be unsuitable for topical application. In this work, we produced hydrogel-thickened nanoemulsions (HTN) using chitosan as thickening polymer to overcome the low viscosity attributed to NE. The aim of this study is to develop and characterize oil-in-water (o/w) HTN based on sweet fennel and clove essential oil to transdermal delivery of 8-methoxsalen (8-MOP). NE components (oil, surfactant) were selected on the basis of solubility and droplet size and processed in a high-pressure homogenizer (HPH). Drug loaded NE and HTN were characterized for particle size, stability under storage and centrifugation, rheological behavior, transdermal permeation and skin accumulation. Transdermal permeation of 8-MOP from HTN was determined by using Franz diffusion cell. Transdermal permeation from HTN using clove essential oil showed strong dependency chitosan molecular weight. On the other hand, HTN using sweet fennel oil showed an unexpected pH-dependent behavior not fully understood at the moment. These results need further investigation, nevertheless HTN revealed to be interesting and complex dermal delivery systems for poorly soluble drugs.

Narrow-band UVB phototherapy and psoralen-ultraviolet A photochemotherapy in the treatment of cutaneous mastocytosis: a study in 20 patients.

BACKGROUND: In mastocytosis, the skin is almost invariably involved, and cutaneous symptoms deeply affect patients' quality of life. METHODS: A retrospective observational analysis of patients affected by cutaneous mastocytosis (CM) and indolent systemic mastocytosis (ISM) treated with phototherapy/photochemotherapy (PUVA or NB-UVB) has been conducted. For each patient, total numbers of PUVA or NB-UVB exposures, the cumulative UV dose (J/cm2 ), serum tryptase profile, and pruritus, before and after treatment, according to the visual analogue scale (VAS) were considered. Skin lesions of each patient were assessed, before and after treatment, according to a cutaneous scale score. RESULTS: Twenty patients affected by CM and ISM were studied; in particular, 10 patients received NB-UVB therapy, and other 10 patients received PUVA. A statistically significant mean reduction of pruritus in both groups (P < 0.01) was observed. The number of treatments necessary to obtain symptom relief was significantly lower in the PUVA group, but the mean exposure dose was significantly higher, if compared to the NB-UVB group. Serum tryptase levels showed a downward trend. The cutaneous score improved in both groups. LIMITATIONS: This study was a retrospective study with a small sample size and without a control group. CONCLUSION: This work provides evidence that both NB-UVB and PUVA represent a safe and useful second-line therapy of the cutaneous symptoms in mastocytosis.

Psoralen and Isopsoralen Ameliorate Sex Hormone Deficiency-Induced Osteoporosis in Female and Male Mice.

Osteoporosis is a systemic skeletal disease, which is characterized by a systemic destruction of bone mass and microarchitecture. With life standard improved, the treatment of osteoporosis attracted more attention. The aim of this study is to verify the osteoprotective effect of psoralen and isopsoralen in females and males. Female and male mice were divided into 7 groups in this study: control group (sham-operation), model group (by ovariectomy or orchidectomy), positive control group (females given estradiol valerate; males given alendronate sodium), psoralen groups (10 mg/kg and 20 mg/kg), and isopsoralen groups (10 mg/kg and 20 mg/kg). After administration of psoralen and isopsoralen for 8 weeks, osteoporosis was ameliorated with increasing bone strength and improving trabecular bone microstructure as indicated by CT scan and pathology. Serum alkaline phosphatase (ALP), tartrate resistant acid phosphatase (TRACP), osteocalcin (OC), and C-terminal cross-linking telopeptides of type I collagen (CTX-1) were examined. Decreased TRACP and increased ALP/TRACP suggested restoring from bone destruction. These results suggest that psoralen and isopsoralen may be used as good natural compounds for the treatment of osteoporosis in males, as well as females.

Phototherapy in the elderly.

BACKGROUND: Elderly patients present with a unique spectrum of dermatoses that pose particular management opportunities and challenges, which will be increasingly encountered in dermatological practice. The skin of elderly patients differs from that of younger patients not only in appearance but also in structure, physiology and response to ultraviolet (UV) radiation. However, little is known about the safety and efficacy of phototherapy in elderly patients and how phototherapy is currently being utilized to treat them. AIM: To investigate the safety, efficacy and utilization of phototherapy in elderly patients. METHODS: In January 2014, we analysed all patients recently referred for, currently receiving or recently having completed a course of phototherapy at a university teaching hospital in England (UK). RESULTS: In total, 249 patients were identified; 37 (15%) were over the age of 65 years (the WHO definition of an elderly or older person). The dermatoses being treated were psoriasis (51%), eczema (11%), nodular prurigo (11%), pruritus (11%), Grover disease (5%) and others (11%). One patient with dementia was deemed not safe to embark on phototherapy, and five patients were yet to start. The remaining 31 elderly patients received 739 individual phototherapy treatments: 88% narrowband (NB)-UVB and 12% systemic, bath and hand/foot psoralen UVA (PUVA). The acute adverse event (AE) rate was 1.89%, all occurring in those receiving NB-UVB. No severe acute AEs occurred. Of those who completed their course of phototherapy, 80% achieved a clear/near clear or moderate response, while just two patients (8%) had minimal response and two (8%) had worsening of the disease during treatment. Of those receiving NB-UVB for psoriasis, 91% achieved a clear or near-clear response. CONCLUSIONS: In this small survey, the first of its kind to focus on elderly patients, phototherapy appears to be well-tolerated, safe and efficacious in the short term. Further thought and investigation should be given to delivering phototherapy to an ageing population.

Systematic review of combination therapies for mycosis fungoides.

BACKGROUND: A variety of therapeutic options are available for mycosis fungoides, the most prevalent subtype of cutaneous T cell lymphomas, but thus far, no regimen has been proven to be curative. A combination of treatments is a well-established strategy to increase the therapeutic efficacy. However, data from clinical trials analyzing such combinations for the treatment of mycosis fungoides are scarce. OBJECTIVE: To analyze the available evidence on combination therapies with emphasis on the combination of psoralen with UVA phototherapy (PUVA), interferon-alpha and bexarotene with another treatment. METHODS: Systematic literature review of the databases Embase, Cochrane, Medline, and Medline in Process. RESULTS: Combination of PUVA with interferon-alpha or retinoids did not result in an increased overall response rate. Addition of methotrexate but not retinoids to interferon-alpha may increase the overall response rate. Bexarotene was investigated in one trial each with vorinostat, methotrexate or gemcitabine, whereby only methotrexate possibly enhanced the effect of bexarotene. CONCLUSION: For mycosis fungoides, no combination treatment has been demonstrated to be superior to monotherapy. Based on our analysis, we conclude that in certain clinical situations, patients may benefit from a combination of PUVA with interferon-alpha or a retinoid or a combination of the latter two. Furthermore, patients in advanced stages may benefit from the combination of methotrexate and interferon-alpha or bexarotene. Finally, the combination of bexarotene with either vorinostat or gemcitabine did not increase the overall response rate but resulted in more pronounced side effects and cannot be recommended.

Comparison of ethosomes and liposomes for skin delivery of psoralen for psoriasis therapy.

Recent reports have indicated that psoriasis may be caused by malfunctioning dermal immune cells, and psoralen ultraviolet A (PUVA) is an effective treatment for this chronic disease. However, conventional topical formulations achieve poor drug delivery across patches of psoriasis to their target sites. The present study describes the development of a novel psoralen transdermal delivery system employing ethosomes, flexible vesicles that can penetrate the stratum corneum and target deep skin layers. An in vitro skin permeation study showed that the permeability of psoralen-loaded ethosomes was superior to that of liposomes. Using ethosomes, psoralen transdermal flux and skin deposition were 38.89±0.32 µg/cm(2)/h and 3.87±1.74 µg/cm(2), respectively, 3.50 and 2.15 times those achieved using liposomes, respectively. The ethosomes and liposomes were found to be safe following daily application to rat skin in vivo, for 7 days. The ethosomes showed better biocompatibility with human embryonic skin fibroblasts than did an equivalent ethanol solution, indicating that the phosphatidylcholine present in ethosome vesicles improved their biocompatibility. These findings indicated that ethosomes could potentially improve the dermal and transdermal delivery of psoralen and possibly of other drugs requiring deep skin delivery.