Liposomes and niosomes as potential carriers for dermal delivery of minoxidil

The aim of this work was to formulate minoxidil loaded liposome and niosome formulations to improve skin drug delivery. Multilamellar liposomes were prepared using soy phosphatidylcholine at different purity degrees (Phospholipon 90, 90% purity, soy lecithin (SL), 75% purity) and cholesterol (Chol), whereas niosomes were made with two different commercial mixtures of alkylpolyglucoside (APG) surfactants (Oramix NS10, Oramix CG110), Chol and dicetylphosphate. Minoxidil skin penetration and permeation experiments were performed in vitro using vertical diffusion Franz cells and human skin treated with either drug vesicular systems or propylene glycol-water-ethanol solution (control). Penetration of minoxidil in epidermal and dermal layers was greater with liposomes than with niosomal formulations and the control solution. These differences might be attributed to the smaller size and the greater potential targeting to skin and skin appendages of liposomal carriers, which enhanced globally the skin drug delivery. The greatest skin accumulation was always obtained with non-dialysed vesicular formulations. No permeation of minoxidil through the whole skin thickness was detected in the present study irrespective of the existence of hair follicles. Alcohol-free liposomal formulations would constitute a promising approach for the topical delivery of minoxidil in hair loss treatment.     

Simultaneous effects of tocopheryl polyethylene glycol succinate (TPGS) on local hair growth promotion and systemic absorption of topically applied minoxidil in a mouse model

In this study, topical minoxidil solutions supplemented with TPGS in cosolvent systems of various compositions consisting of water, alcohol, and polyethylene glycol 400 were designed to evaluate the efficacy of promoting hair growth after topical application and the safety in terms of the amount of minoxidil absorbed through the skin into the circulation using C57BL/6J mice as a model. The commercial product of 2% Regaine) was used as the positive control. The role, which sulfotransferase activity plays in hair growth with treatment using minoxidil, was determined as well. The results revealed that the addition of 0.5% TPGS was able to enhance the proliferation of hair, but an increase in the amount of TPGS to 2% led to deterioration in the enhancement of hair growth. At the higher added amount (2.0%) of TPGS, the promotion of hair growth was slightly reduced for both cosolvent formulations F1 (100% water) and F3 (100% PEG 400), whereas it was reduced to a greater extent for the cosolvent formulations F8-F10. In comparison, the influences of cosolvent compositions with TPGS amounts of 0.0 and 2.0% on the promotion of hair growth were similar. On the contrary, variability in the promotion of hair growth by different solvent formulations was minimal when the added amount of TPGS was 0.5%. In general, a relationship between hair growth and sulfotransferase activities after topical application of 2% Regaine and minoxidil formulations containing various amounts of TPGS was not demonstrated. Plasma concentrations of minoxidil with 2% Regaine were found to be greater than those of 2% minoxidil in those cosolvent formulations containing various amounts of TPGS, while showing insignificant differences among those 10 cosolvent formulations with a fixed amount of TPGS. A tendency for the plasma concentration of minoxidil to increase after the topical administration of minoxidil formulations containing the higher amount of TPGS (2%) was noted.     

Penetration enhancer-containing vesicles (PEVs) as carriers for cutaneous delivery of minoxidil

The aim of this work was to evaluate the ability of a few different penetration enhancers to produce elastic vesicles with soy lecithin and the influence of the obtained vesicles on in vitro (trans)dermal delivery of minoxidil. To this purpose, so-called Penetration Enhancer-containing Vesicles (PEVs) were prepared as dehydrated–rehydrated vesicles by using soy lecithin and different amounts of three penetration enhancers, 2-(2-ethoxyethoxy)ethanol (Transcutol^®), capryl-caproyl macrogol 8-glyceride (Labrasol^®), and cineole. Soy lecithin liposomes, without penetration enhancers, were used as control. Prepared formulations were characterized in terms of size distribution, morphology, zeta potential, and vesicle deformability.The influence of PEVs on (trans)dermal delivery of minoxidil was studied by in vitro diffusion experiments through newborn pig skin in comparison with traditional liposomes and ethanolic solutions of the drug also containing each penetration enhancer. A skin pre-treatment study using empty PEVs and conventional liposomes was also carried out.Results showed that all the used penetration enhancers were able to give more deformable vesicles than conventional liposomes with a good drug entrapment efficiency and stability. In vitro skin penetration data showed that PEVs were able to give a statistically significant improvement of minoxidil deposition in the skin in comparison with classic liposomes and penetration enhancer-containing drug ethanolic solutions without any transdermal delivery. Moreover, the most deformable PEVs, prepared with Labrasol^® and cineole, were also able to deliver to the skin a higher total amount of minoxidil than the PE alcoholic solutions thus suggesting that minoxidil delivery to the skin was strictly correlated to vesicle deformability, and therefore to vesicle composition.     

Topical minoxidil therapy for hair regrowth

The pathogenesis of hair loss, the postulated mechanisms of minoxidil action on hair growth, and clinical trials, adverse reactions, experimental formulations, and percutaneous absorption of topical minoxidil preparations are reviewed. Topical minoxidil seems to normalize hair follicles and increase blood flow to the scalp. In clinical trials of various formulations, results have varied. Improved hair growth occurred after four to six months of therapy; twice-daily application seems to be indicated. The most frequently reported adverse reactions are mild scalp dryness and irritation and, rarely, allergic contact dermatitis. Current recommendations are to reserve topical minoxidil for patients with normal cardiovascular status and to routinely monitor blood pressure, heart rate, and electrocardiographic changes. A new drug application is pending with FDA for use of topical minoxidil in androgenetic alopecia (male-pattern baldness), which is genetically determined and apparently stimulated by androgens. For alopecia areata, which involves hair loss on the body or scalp, usually patchy and of sudden onset, no reliable treatment has been found, although minoxidil may be efficacious in some patients. Minoxidil has generated new interest in hair-loss research. The etiology of hair loss must be better understood before more effective treatment regimens can be designed.     

Chitosan microparticles for sustaining the topical delivery of minoxidil sulphate

Given the hypothesis that microparticles can penetrate the skin barrier along the transfollicular route, this work aimed to obtain and characterise chitosan microparticles loaded with minoxidil sulphate (MXS) and to study their ability to sustain the release of the drug, attempting a further application utilising them in a targeted delivery system for the topical treatment of alopecia. Chitosan microparticles, containing different proportions of MXS/polymer, were prepared by spray drying and were characterised by yield, encapsulation efficiency, size and morphology. Microparticles selected for further studies showed high encapsulation efficiency (～82%), a mean diameter of 3.0?µm and a spherical morphology without porosities. When suspended in an ethanol/water solution, chitosan microparticles underwent instantaneous swelling, increasing their mean diameter by 90%. Release studies revealed that the chitosan microparticles were able to sustain about three times the release rate of MXS. This feature, combined with suitable size, confers to these microparticles the potential to target and improve topical therapy of alopecia with minoxidil.     

Chitosan microparticles for sustaining the topical delivery of minoxidil sulphate

Given the hypothesis that microparticles can penetrate the skin barrier along the transfollicular route, this work aimed to obtain and characterise chitosan microparticles loaded with minoxidil sulphate (MXS) and to study their ability to sustain the release of the drug, attempting a further application utilising them in a targeted delivery system for the topical treatment of alopecia. Chitosan microparticles, containing different proportions of MXS/polymer, were prepared by spray drying and were characterised by yield, encapsulation efficiency, size and morphology. Microparticles selected for further studies showed high encapsulation efficiency (～82%), a mean diameter of 3.0?μm and a spherical morphology without porosities. When suspended in an ethanol/water solution, chitosan microparticles underwent instantaneous swelling, increasing their mean diameter by 90%. Release studies revealed that the chitosan microparticles were able to sustain about three times the release rate of MXS. This feature, combined with suitable size, confers to these microparticles the potential to target and improve topical therapy of alopecia with minoxidil.     

Lecithin microemulsions for the topical administration of ketoprofen: percutaneous adsorption through human skin and in vivo human skin tolerability

The potential application of highly biocompatible o/w microemulsions as topical drug carrier systems for the percutaneous delivery of anti-inflammatory drugs, i.e. ketoprofen, was investigated. Microemulsions were made up of triglycerides as oil phase, a mixture of lecithin and n-butanol as a surfactant/co-surfactant system and an aqueous solution as the external phase. To evaluate the percutaneous enhancing effect of oleic acid, this compound was used as a component of some o/w microemulsions. The topical carrier potentialities of lecithin-based o/w microemulsions were compared with respect to conventional formulations, i.e. a w/o emulsion, a o/w emulsion and a gel. Physicochemical characterisation of microemulsions was carried out by light scattering and zeta potential analyses. Microemulsions showed mean droplet size < 35 nm and a negative zeta potential, that is -39.5 mV for the oleic acid-lecithin microemulsion and -19.7 mV for the lecithin-based microemulsion. The percutaneous adsorption of the various topical formulations was evaluated through healthy adult human skin, which was obtained from abdominal reduction surgery. Ketoprofen-loaded microemulsions showed an enhanced permeation through human skin with respect to conventional formulations. No significant percutaneous enhancer effect was observed for ketoprofen-loaded oleic acid-lecithin microemulsions. The human skin tolerability of various microemulsion formulations was evaluated on human volunteers. Microemulsions showed a good human skin tolerability.     

Squarticles as a Lipid Nanocarrier for Delivering Diphencyprone and Minoxidil to Hair Follicles and Human Dermal Papilla Cells

Delivery of diphencyprone (DPCP) and minoxidil to hair follicles and related cells is important in the treatment of alopecia. Here we report the development of “squarticles,” nanoparticles formed from sebum-derived lipids such as squalene and fatty esters, for use in achieving targeted drug delivery to the follicles. Two different nanosystems, nanostructured lipid carriers (NLC) and nanoemulsions (NE), were prepared. The physicochemical properties of squarticles, including size, zeta potential, drug encapsulation efficiency, and drug release, were examined. Squarticles were compared to a free control solution with respect to skin absorption, follicular accumulation, and dermal papilla cell targeting. The particle size of the NLC type was 177 nm; that of the NE type was 194 nm. Approximately 80% of DPCP and 60% of minoxidil were entrapped into squarticles. An improved drug deposition in the skin was observed in the in vitro absorption test. Compared to the free control, the squarticles reduced minoxidil penetration through the skin. This may indicate a minimized absorption into systemic circulation. Follicular uptake by squarticles was 2- and 7-fold higher for DPCP and minoxidil respectively compared to the free control. Fluorescence and confocal images of the skin confirmed a great accumulation of squarticles in the follicles and the deeper skin strata. Vascular endothelial growth factor expression in dermal papilla cells was significantly upregulated after the loading of minoxidil into the squarticles. In vitro papilla cell viability and in vivo skin irritancy tests in nude mice suggested a good tolerability of squarticles to skin. Squarticles provide a promising nanocarrier for topical delivery of DPCP and minoxidil.     

The additive effects of minoxidil and retinol on human hair growth in vitro

Minoxidil enhances hair growth by prolonging the anagen phase and induces new hair growth in androgenetic alopecia (AGA), whereas retinol significantly improves scalp skin condition and promotes hair growth. We investigated the combined effects of minoxidil and retinol on human hair growth in vitro and on cultured human dermal papilla cells (DPCs) and epidermal keratinocytes (HaCaT). The combination of minoxidil and retinol additively promoted hair growth in hair follicle organ cultures. In addition, minoxidil plus retinol more effectively elevated phosphorylated Erk, phosphorylated Akt levels, and the Bcl-2/Bax ratio than minoxidil alone in DPCs and HaCaT. We found that the significant hair shaft elongation demonstrated after minoxidil plus retinol treatment would depend on the dual kinetics associated with the activations of Erk- and Akt-dependent pathways and the prevention of apoptosis by increasing the Bcl-2/Bax ratio.     

Lecithin-based cationic nanoparticles as a potential DNA delivery system

Previously, we have reported a novel nanoparticle-based DNA vaccine delivery system, which elicited strong immune responses against antigens of interest encoded by the DNA. The nanoparticles were engineered by cooling pre-formed warm microemulsions comprised of emulsifying wax as the oil phase and hexadecyltrimethyl ammonium bromide (CTAB) as the surfactant. However, the poor aqueous stability of the nanoparticles and the emulsifying wax in the nanoparticles may severely limit the applications of the nanoparticles. In the present study, we used lecithin, a more biocompatible material, instead of emulsifying wax, to prepared lecithin-based cationic nanoparticles. The 50% growth inhibition concentration (IC(50)) of the lecithin-based nanoparticles was found to be more than 1,000-fold higher than that of the emulsifying wax-based nanoparticles. Moreover, the stability of the lecithin nanoparticles was also significantly increased. The size of the nanoparticles did not significantly change during a 6-month storage period at room temperature. Finally, when plasmid DNA was adsorbed on their surface, the lecithin nanoparticles successfully transfected cells in culture. These lecithin-based nanoparticles may hold great potentials as a DNA (vaccine) delivery system.     

Topical minoxidil. A preliminary review of its pharmacodynamic properties and therapeutic efficacy in alopecia areata and alopecia androgenetica

When minoxidil is administered orally for periods in excess of 1 month, hypertrichosis occurs as a side effect in a majority of patients. Consequently, topical minoxidil has been developed to try to improve hair growth in patients with alopecia areata and alopecia androgenetica. Preliminary studies have shown that topical minoxidil promotes cosmetically acceptable hair regrowth in a variable proportion of patients with alopecia areata. Data from a large multicentre trial indicate that cosmetically worthwhile results are achieved in about one-third of subjects with alopecia androgenetica after 1 year of treatment. A much higher proportion (about 80%) of patients with alopecia androgenetica exhibited some non-vellus hair regrowth after 1 year, and whether more of these patients would develop a cosmetically acceptable result with a longer treatment period is an important area of future investigation. Initial indications suggest that less severe disease is a predictor of likely response. Thus, topical minoxidil would seem to be a useful treatment modality for patients with alopecia androgenetica--a disease for which no other safe and effective drug therapy exists. Results from treating patients with alopecia areata with topical minoxidil, although encouraging, have been more variable and require further evaluation. Even though a number of questions remain to be answered about topical minoxidil (as would be expected at this stage in its development), it would seem to be the first available drug with the potential to promote substantial hair regrowth in these divergent diseases.     

Effect of Citrullus colocynthis. on Hair Growth in Albino Rats

Abstract

Citrullus colocynthis. Schrad (Cucurbitaceae) is a traditionally acclaimed hair tonic in Ayurveda (the traditional Indian system of medicine). Studies were therefore undertaken to evaluate petroleum ether and ethanol extracts of C. colocynthis. for their effect on hair growth in albino rats. The extracts incorporated into oleaginous ointment base were applied topically on shaved denuded skin of albino rats. The time required for initiation of hair growth as well as completion of hair growth cycle was recorded. Minoxidil 2% solution was applied topically and served as the standard. Hair growth initiation time was significantly reduced to half on treatment with the petroleum ether extracts compared with untreated control animals. The time required for complete hair growth was also considerably reduced. The treatment was successful in bringing a greater number of hair follicles (>70%) to anagenic phase than standard minoxidil (67%). The result of treatment with 2 and 5% petroleum ether extracts were comparable with the standard minoxidil.     

Penetration enhancer-containing vesicles (PEVs) as carriers for cutaneous delivery of minoxidil: in vitro evaluation of drug permeation by infrared spectroscopy

Recently, we carried out a research on new liposomal systems prepared by using in their composition a few penetration enhancers which differ for chemical structure and physicochemical properties. The penetration enhancer-containing vesicles (PEVs) were prepared by using soy lecithin and different amounts of three penetration enhancers, 2-(2-ethoxyethoxy) ethanol (Transcutol^®), capryl-caproyl macrogol 8-glyceride (Labrasol^®), and cineole.To study the influence of the PEVs on (trans)dermal delivery of minoxidil, in vitro diffusion experiments were performed through new born pig skin and the results were compared with that obtained applying the vesicular system without enhancer (control) after pretreatment of the skin with the various enhancers. In this study, Fourier transform infrared spectroscopy (FTIR), attenuated total reflectance FTIR (ATR-FTIR) and FTIR imaging were used to evaluate the effective penetration of minoxidil in the skin layers and to discover the influence of the enhancer on the drug topical delivery. These analytical studies allowed us to characterize the drug formulations and to evaluate the vesicle distribution into the skin. Recorded spectra confirmed that the vesicle formulations with penetration enhancers promoted drug deposition into the skin.     

Solid lipid nanoparticles suspension versus commercial solutions for dermal delivery of minoxidil

Solid lipid nanoparticles have been reported as possible carrier for skin drug delivery. Solid lipid nanoparticles are produced from biocompatible and biodegradable lipids. Solid lipid nanoparticles made of semi-synthetic triglycerides stabilized with a mixture of polysorbate and sorbitan oleate were loaded with 5% of minoxidil. The prepared systems were characterized for particle size, pH and drug content. Ex vivo skin penetration studies were performed using Franz-type glass diffusion cells and pig ear skin. Ex vivo skin corrosion studies were realized with a method derived from the Corrositex^® test. Solid lipid nanoparticles suspensions were compared to commercial solutions in terms of skin penetration and skin corrosion. Solid lipid nanoparticles suspensions have been shown as efficient as commercial solutions for skin penetration; and were non-corrosive while commercial solutions presented a corrosive potential. Solid lipid nanoparticles suspensions would constitute a promising formulation for hair loss treatment.     

Monilethrix treated with minoxidil

In literature many different therapies are proposed to treat Monilethrix, but a definitive therapy still doe not exist. We decided to treat four patients affected by Monilethrix, with topical minoxidil 2%, 1 ml night and day for 1 year. Minoxidil led to a an increase of normal hair shaft without any side effects in all the patients. Therefore topical minoxidil 2% could be considered a good therapy to treat Monilethrix.     

Isotretinoin-loaded solid lipid nanoparticles with skin targeting for topical delivery

The purpose of this study was to construct isotretinoin-loaded SLN (IT-SLN) formulation with skin targeting for topical delivery of isotretinoin. PRECIROL ATO 5 was selected as the lipid of SLN. Tween 80 and soybean lecithin were used as the surfactants to stabilize SLN. The hot homogenization method was performed to prepare the drug-loaded SLN. The various formulations were characterized by photon correlation spectroscopy and all the SLN formulations had low average size between 30 and 50 nm. Transmission electron microscopy studies showed that the IT-SLN formulation had a spherical shape. All the formulations had high entrapment efficiency ranging from 80% to 100%. The penetration of isotretinoin from the IT-SLN formulations through skins and into skins were evaluated in vitro using Franz diffusion cells fitted with rat skins. The in vitro permeation data showed that all the IT-SLN formulations can avoid the systemic uptake of isotretinoin in skins, however the control tincture had a permeation rate of 0.76+/-0.30 microg cm(-2)h(-1) through skins. The IT-SLN consisting of 3.0% PRECIROL ATO 5, 4.0% soybean lecithin and 4.5% Tween 80 could significantly increased the accumulative uptake of isotretinoin in skin and showed a significantly enhanced skin targeting effect. The studied IT-SLN showed a good stability. These results indicate that the studied IT-SLN formulation with skin targeting may be a promising carrier for topical delivery of isotretinoin.     

New topical antiandrogenic formulations can stimulate hair growth in human bald scalp grafted onto mice

The purpose of this study was to test the ability of topical formulations of finasteride and flutamide to re-enlarge hair follicles in male-pattern baldness. This was evaluated by an experimental model of human scalp skin graft transplanted onto SCID mice. A comparison was made between formulations containing finasteride and flutamide, and a vehicle formulation in terms of the mean hairs per graft, length, diameter of the shafts, and structures of the growth stages of the hair. Flutamide and finasteride had a significantly higher effect (P<0.05) than the placebo in all the tested parameters, but flutamide demonstrated more hair per graft and longer hair shafts than finasteride (P<0.05). The number of hairs per graft for flutamide and finasteride groups were 1.22+/-0. 47 and 0.88+/-0.95 hairs/0.5 mm2 graft, respectively, versus 0. 35+/-0.6 hairs/graft for vehicle-treated graft. Similarly, hair lengths for flutamide and finasteride were 5.82+/-0.50 and 4.50+/-0. 32 mm, respectively, versus 2.83+/-0.18 mm for the vehicle-treated grafts. An in vitro diffusion study of flutamide gel using hairless mouse skin demonstrated the beneficial effect of the vehicle composition in comparison with a hydroalcoholic solution or a gel containing no penetration enhancer. It is therefore suggested that this topical composition containing flutamide or finasteride may effectively result in regression of male-pattern baldness.     

Effect of vehicles and enhancers on the topical delivery of cyclosporin A

Topical delivery of cyclosporin a (CysA) is of great interest for the treatment of autoimmune skin disorders. The purpose of this study was to investigate the effect of various vehicles and enhancers on the topical delivery across rat skin. The topical (to the skin) delivery of CysA was evaluated in vitro using rat skin mounted in a Franz diffusion cell. CysA was analyzed by UV-HPLC. As vehicles, CysA vehicle containing 40% ethanol showed significantly enhanced deposition of CysA into the stratum corneum (SC) and deeper skin, as compared to other vehicles. The efficiency of the vehicles to improve the topical delivery of CysA was sequenced in the order of: 40% ethanol>ethyl oleate>Transcutol>isopropyl myristate>ethanol>Labrasol>propylene glycol>Lauroglycol FCC. Next, we tested effect of pre-treatment with chemical enhancers on the penetration of CysA. The permeation-enhancer effect of enhancers was in the following order: 10% menthol approximately 0.05% SLS>5% Azone>5% NMP>5% DEMO. Moreover, chemical enhancers shortened the lag time of the penetration of CysA into deeper skin. The present study suggests that the suspension of 40% ethanol containing 0.5% drug can more effectively enhance the topical delivery of CysA after skin pre-treatment with 10% menthol or 0.05% SLS.     

Nongenotoxicity of minoxidil in murine hair follicles as determined by the nuclear aberration assay

A 1-cm2 area on the back of CD1 mice was prepared for topical application of minoxidil, N-methyl-N-nitrosourea (MNU), or cyclophosphamide (CY) by clipping or plucking hair from a patch of skin. Plucking stimulates hair follicle cell division while clipping does not. Minoxidil was topically administered for 8 consecutive days. CY or MNU was administered topically once on the eighth day postplucking. The incidence of nuclear aberrations and mitotic figures were measured in hair follicles while frequency of micronuclei and the ratio of RBC/PCE were measured in the bone marrow. Results with minoxidil showed no increase in either nuclear aberrations in the hair follicle or micronuclei in the bone marrow. These results suggest that topically applied minoxidil is not genotoxic. In contrast, a dose-dependent effect of MNU on the incidence of nuclear aberrations in the hair follicle was seen. CY induced a dose-dependent increase in the incidence of micronuclei in the bone marrow and in nuclear aberrations in the hair follicle after topical application. Minoxidil applied to clipped mice significantly increased the incidence of mitotic figures above that seen in both the clipped and plucked controls. This suggests that minoxidil is a mitogenic agent in the hair follicle. These findings are consistent with the success of topically applied minoxidil in the treatment of alopecia areata.     

Doxorubicin skin penetration from monoolein-containing propylene glycol formulations

Topical chemotherapy with the antineoplastic doxorubicin (DXR) could be an alternative to treat skin cancer, however its poor skin penetration often limits the efficacy of topical formulations. The aim of this work was to study the effect of monoolein (MO), a penetration enhancer, on the in vitro skin permeation and retention of DXR. DXR was incorporated in a propylene glycol preparation containing 0-20% of MO. DXR release rate and topical delivery were evaluated in vitro using acetate cellulose membrane and porcine skin, respectively, mounted in a Franz diffusion cell. At 5%, MO did not significantly change DXR release rate, but MO concentrations larger than 10% decreased almost twice its release. In vitro skin penetration studies showed that the presence of MO in the propylene glycol formulations markedly increased DXR presence in the stratum corneum (SC). At 5%, MO significantly increased the amount of DXR in the SC already in the first hours, attained a maximum in 6h. Comparing propylene glycol formulations containing more than 10% MO with that containing 5%, the former took the double of the time (12h) to reach the same amount of DXR in the skin, result that is in agreement with in vitro release studies. Interesting, despite the fact that MO significantly increased the amount of DXR in the SC, drug transdermal delivery did not change. These findings suggest a cutaneous delivery of DXR that is an important condition for topical treatment of skin tumors. Further in vivo experiments can show DXR delivery to deeper skin layers.