Enhancement of Topical Delivery from Biodegradable Nanoparticles

Advances in psoriasis physiopathology and treatments: Up to date of mechanistic insights and perspectives of novel therapies based on innovative skin drug delivery systems (ISDDS)

Psoriasis is a chronic inflammatory disease affecting mainly the skin but which can be complicated by psoriatic arthritis (PsA).This autoimmune skin disorder concerns 2-5% of the world population. To date, the physiopathology of psoriasis is not still completely elucidated but many researches are ongoing which have led for example to the discovery of the Th17/Th22 pathway. The conventional therapeutic approaches (local or systemic route) appeal to various classes of drugs with complex mechanisms of action and non-negligible side effects. Although there is no therapy capable to cure psoriasis, the current goal is to relieve symptoms as longer as possible with a good benefit/risk ratio. That is one of the principal limits of conventional antipsoriatic drugs. New formulations based on nanoencapsulation are a promising opportunity to answer to this limit by offering an optimization of the conventional antipsoriatic drug use (higher activity, lower side effects and frequency of application, etc.). Herein, we tried to put in perspective the mechanistic insights (histological and immunological views) proposed into scientific literature these last years in order to have a better comprehension of psoriasis physiopathology resulting in skin lesions and PsA. The therapeutic armamentarium and the different strategies in the management of psoriasis are discussed in greater details. To finish, the field of encapsulation in nanoparticles is broached in order to put forward recent advances in innovative skin drug delivery systems (ISDDSs) of antipsoriatic active agents for a better efficacy, safety and compliance.

Biopharmaceutical profile of hydrogels containing pranoprofen-loaded PLGA nanoparticles for skin administration: In vitro, ex vivo and in vivo characterization

Pranoprofen (PF)-loaded nanoparticles (PF-F1NPs and PF-F2NPs) have been formulated into blank hydrogels (HG_PF-F1NPs and HG_PF-F1NPs) or into hydrogels composed of 3% azone (HG_PF-F1NPs-Azone and HG_PF-F2NPs-Azone), as innovative strategy to improve the biopharmaceutical profile of the selected non-steroidal anti-inflammatory drug (Pranoprofen, PF) for topical application. The purpose of this approach has been to increase the contact of PF with the skin, improve its retention in deeper layers, thus enhancing its anti-inflammatory and analgesic effects. The physicochemical characterization of the developed hydrogels showed a non-Newtonian behaviour, typical of semi-solid formulations for skin administration, with sustained release profile. The results obtained from ex vivo skin human permeation and in vivo anti-inflammatory efficacy studies suggest that topical application of HG_PF-F2NPs has been more effective in the treatment of oedema on the skin' surface in comparison to other hydrogels. No signs of skin irritancy have been detected for all the semi-solid formulations containing 0% or 3% azone.

Chloramphenicol encapsulated in poly-ε-caprolactone-pluronic composite: nanoparticles for treatment of MRSA-infected burn wounds

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) infection has increased precipitously over the past several decades, with far-reaching health care and societal costs. MRSA infections in the context of burn wounds lead to invasive disease that could potentially cause mortality. Chloramphenicol is a well-known broad-spectrum bacteriostatic antibiotic that has been used since 1949, but due to its hydrophobicity, poor penetration in skin, fast degradation, and toxicity, its application has been hindered. Furthermore, it has been demonstrated that old antibiotics such as chloramphenicol remained active against a large number of currently prevalent resistant bacterial isolates due to their low-level use in the past. Recently, the novel nanoparticulate drug-delivery system has been used and reported to be exceptionally useful for topical therapeutics, due to its distinctive physical characteristics such as a high surface-to-volume ratio and minuscule size. It helps to achieve better hydrophilicity, bioavailability, and controlled delivery with enhanced therapeutic index, which has resulted in decreased toxicity levels compared to the crude drug. Here, we report a novel chloramphenicol loaded with poly(ε-caprolactone) (PCL)-pluronic composite nanoparticles (CAM-PCL-P NPs), physicochemical characterizations, and its bioactivity evaluation in a MRSA-infected burn-wound animal model. CAM-PCL-P NPs could encapsulate 98.3% of the drug in the nanoparticles and release 81% of the encapsulated drug over 36 days with a time to 50% drug release of 72 hours (51%). Nanoparticle suspensions maintained the initial properties with respect to size and encapsulation efficiency, even after 6 months of storage at 4°C and 25°C, respectively (P>0.05). Significant reduction in the level of toxicity was observed for CAM-PCL-P NPs compared with that of free drug as confirmed from hemolytic activity against human blood erythrocytes and cytotoxicity assay against an MCF-7 breast cancer cell line. In vitro antibacterial activities were performed by zone of inhibition, minimum inhibitory concentrations, minimum bacterial concentration, and time-kill assays, which showed that CAM-PCL-P NPs exhibited significantly enhanced anti-MRSA activity against ten clinical isolates of MRSA strains. The augmented activity of CAM-PCL-P NPs was further tested on a MRSA-infected burn-wound animal model and achieved quicker efficacy in MRSA clearance and improved the survival rate compared with free-chloramphenicol treatment. Thus, we propose CAM-PCL-P NPs as a promising novel antimicrobial candidate that may have a good potential for preclinical applications.

Enhanced dermal delivery of acyclovir using solid lipid nanoparticles

The present investigation was enthused by the possibility to develop solid lipid nanoparticles (SLNs) of hydrophilic drug acyclovir (ACV) and evaluate their potential as the carrier for dermal delivery. ACV-loaded SLNs (ACV-SLNs) were prepared by the optimized double emulsion process using Compritol 888 ATO as solid lipid. The prepared SLNs were smooth and spherical in shape with average diameter, polydispersity index, and entrapment efficiency of 262 ± 13 nm, 0.280 ± 0.01, and 40.08 ± 4.39% at 10% (w/w) theoretical drug loading with respect to Compritol 888 ATO content. Differential scanning calorimetry and powder X-ray diffraction pattern revealed that ACV was present in the amorphous state inside the SLNs. In vitro skin permeation studies on human cadaver and Sprague-Dawley rat skin revealed 17.65 and 15.17 times higher accumulation of ACV-SLNs in the dermal tissues in comparison to commercially available ACV cream after 24 h. Mechanism of topical permeation and dermal distribution was studied qualitatively using confocal laser scanning microscopy. While free dye (calcein) failed to penetrate skin barrier, the same encapsulated in SLNs penetrated deeply into the dermal tissue suggesting that pilosebaceous route was followed by SLNs for skin penetration. Histological examination and transdermal epidermal water loss measurement suggested that no major morphological changes occurred on rat skin surface due to the application of SLNs. Overall, it was concluded that ACV-loaded SLNs might be beneficial in improving dermal delivery of antiviral agent(s) for the treatment of topical herpes simplex infection.

A holistic approach to targeting disease with polymeric nanoparticles

The primary goal of nanomedicine is to improve clinical outcomes. To this end, targeted nanoparticles are engineered to reduce non-productive distribution while improving diagnostic and therapeutic efficacy. Paradoxically, as this field has matured, the notion of targeting has been minimized to the concept of increasing the affinity of a nanoparticle for its target. This Opinion article outlines a holistic view of nanoparticle targeting, in which the route of administration, molecular characteristics and temporal control of the nanoparticles are potential design variables that must be considered simultaneously. This comprehensive vision for nanoparticle targeting will facilitate the integration of nanomedicines into clinical practice.

Treating cutaneous squamous cell carcinoma using 5-aminolevulinic acid polylactic-co-glycolic acid nanoparticle-mediated photodynamic therapy in a mouse model

Background

Squamous cell carcinoma (SCC) is a common skin cancer, and its treatment is still difficult. The aim of this study was to evaluate the effectiveness of nanoparticle (NP)-assisted 5-aminolevulinic acid (ALA) delivery for topical photodynamic therapy (PDT) of cutaneous SCC.

Materials and methods

Ultraviolet-induced cutaneous SCCs were established in hairless mice. ALA-loaded polylactic-co-glycolic acid (PLGA) NPs were prepared and characterized. The kinetics of ALA PLGA NP-induced protoporphyrin IX fluorescence in SCCs, therapeutic efficacy of ALA NP-mediated PDT, and immune responses were examined.

Results

PLGA NPs enhanced protoporphyrin IX production in SCC. ALA PLGA NP-mediated topical PDT was more effective than free ALA of the same concentration in treating cutaneous SCC.

Conclusion

PLGA NPs provide a promising strategy for delivering ALA in topical PDT of cutaneous SCC.

Effects of 3,5,3′-Triiodothyroacetic Acid, Nanoencapsulated or Not, on Intact and Atrophic Skin in Rats

We aimed to investigate 3,5,3′-triiodothyroacetic acid (TRIAC) effects on intact and atrophic skin induced by glucocorticoids (GCs) in rats and the effects induced by nanoencapsulation. The effects of TRIAC and nanoencapsulated TRIAC were evaluated on intact and atrophic skin in TRIAC experiment and nanoencapsulated TRIAC experiment, respectively. Both experiments had two phases: phase I, cutaneous atrophy was induced; phase II, TRIAC or nanoencapsulated TRIAC was administrated. Our results showed that topical use of TRIAC with or without nanoencapsulation was able to reverse cutaneous atrophy. Nanoencapsulated TRIAC showed less systemic changes than TRIAC; therefore, it is possibly a safer drug for topical administration.

Nanotechnology in dermatology

The scientific community and general public have been exposed to a series of achievements attributed to a new area of knowledge: Nanotechnology. Both abroad and in Brazil, funding agencies have launched programs aimed at encouraging this type of research. Indeed, for many who come into contact with this subject it will be clear the key role that chemical knowledge will play in the evolution of this subject. And even more, will see that it is a science in which the basic structure is formed by distilling different areas of inter-and multidisciplinary knowledge along the lines of new paradigms. In this article, we attempt to clarify the foundations of nanotechnology, and demonstrate their contribution to new advances in dermatology as well as medicine in general. Nanotechnology is clearly the future.

Investigation of ethyl cellulose microsponge gel for topical delivery of eberconazole nitrate for fungal therapy

Background: The aim of the study was to investigate ethyl cellulose microsponges as topical carriers for the controlled release and cutaneous drug deposition of eberconazole nitrate (EB). Materials & method: EB microsponges were prepared using the quasiemulsion solvent diffusion method. The effect of formulation variables (drug:polymer ratio, internal phase volume and amount of emulsifier) and process variables (stirring time and stirring speed) on the physical characteristics of microsponges were investigated. The optimized microsponges were dispersed into a hydrogel and evaluated. Results & discussion: Spherical and porous EB microsponge particles were obtained. The optimized microsponges possessed particle size, drug content and entrapment efficiency of 24.5 µm, 43.31% and 91.44%, respectively. Microsponge-loaded gels demonstrated controlled release, nonirritancy to rat skin and antifungal activity. An in vivo skin deposition study demonstrated fourfold higher retention in the stratum corneum layer as compared with commercial cream. Conclusion: Developed ethyl cellulose microsponges could be potential pharmaceutical topical carriers of EB in antifungal therapy.

Enhanced cutaneous bioavailability of dehydroepiandrosterone mediated by nano-encapsulation

Polymeric nanocarriers, especially nanospheres (NSs) and nanocapsules (NCs), can promote the penetration of their cargo through the skin barrier, towards improved cutaneous bioavailability. Dehydroepiandrosterone (DHEA), an endogenous hormone exhibiting poor aqueous solubility, was shown to be effective in modulating skin-aging processes following topical application. In this study, we designed adequate DHEA preparations, in an attempt to enable local delivery of the active ingredient to the viable skin layers. In addition, the potential efficiency of DHEA NCs on dermal collagen synthesis was evaluated. Cryo-TEM observations and thermal analysis indicated that DHEA was successfully incorporated within a stable NC-based delivery system. Moreover, higher [(3)H]-DHEA levels were recorded in the viable skin layers following different incubation periods of NCs on excised pig skin specimens as compared to DHEA oil solution (free molecule). Furthermore, significantly higher (4-fold) skin flux values were observed for the DHEA NCs as compared to the values elicited by the oil control solution. Finally, collagen synthesis in human skin organ culture, assessed by the incorporation of [(3)H]-proline, was up to 42% higher for DHEA NCs 48h post-topical application than for the untreated specimens. Overall, these results suggest that poly lactic-co-glycolic acid (PLGA)-based NCs have promising potential to be used topically for various skin disorders.

Biocompatible nanoparticles for sustained topical delivery of anticancer phytoconstituent quercetin

This study describes the release and retention of a herbal lipophilic drug in sustained and controlled manner in skin layers, given topically, intended for skin cancer. Quercetin -loaded nanoparticles were prepared by nanoprecipitation technique using ethylcellulose as polymer. Ethylcellulose was selected as it is biocompatible, but non-biodegradable and hence can act as a reservoir in skin furrows and ducts. It was observed that the Quercetin: Ethylcellulose: Tween 80 at different ratios affects particle sizes along with yield and entrapment efficiency. It was found that the size of nanoparticles could be varied by changing the speed of agitation and sonication. The nanoparticles were prepared in particle size range 228.77 +/- 2.0 nm and the zeta potential of the selected formulation were found to be -16.7 mV, which shows the stability of the preparation. The percent entrapment efficiency was found to be in the range from 51.96 to 53.93% and percent loading capacity in the range 34.19 to 5.12%. The amount of drug release from nanoparticles and of drug retained in skin was compared using ex vivo study which shows that the drug being lipophilic could be retained in the skin for longer duration thus reducing the dose and frequency of drug administration. Further the amount of drug reaching to other organs is also reduced since the systemic absorption of drug was low. Thus, Quercetin loaded nanoparticles were prepared for topical use.

Effect of non-phospholipid-based cationic and phospholipid-based anionic nanosized emulsions on skin retention and anti-inflammatory activity of celecoxib

CONTEXT

Celecoxib (CXB, 0.2 g)-loaded anionic and cationic nanosized emulsions were prepared by a well-established combined emulsification method.

OBJECTIVES

To investigate the effect of non-phospholipid-based cationic and phospholipid-based anionic emulsions on skin retention and anti-inflammatory activity of CXB.

METHODS

Using Keshary-Chien diffusion cells with cellulose acetate membrane or excised rat skin, in vitro release and skin retention of CXB from solution and emulsions were studied. The anti-inflammatory activity was evaluated by the carrageenan-induced hind paw edema method in Wistar rats.

RESULTS

The amount of drug released through artificial membrane has decreased from 122.00 ± 0.70 μg/cm(2) for the CXB solution to 55.80 ± 0.70 μg/cm(2) for anionic emulsion, and then further decreased to 24.79 ± 0.90 μg/cm(2) for cationic emulsion. The JSS value obtained with solution, anionic, and cationic emulsions were 6825.79 ± 920.86, 2513.15 ± 382.71, and 1925.67 ± 147.42, respectively. Cationic emulsion showed a significantly higher level (P ≤ 0.05) of drug accumulation in full-thickness rat skin than anionic emulsion, and a substantially lesser percentage inhibition of edema values compared with both solution and anionic emulsion.

DISCUSSION AND CONCLUSION

Sustained drug release together with increased skin accumulation and simultaneously decreased skin permeation as observed with cationic emulsion should substantiate its suitability as a topical delivery vehicle for CXB.

Design of polymeric nanoparticles and its applications as drug delivery systems for acne treatment

OBJECTIVE

The aim of this study was to evaluate a formulation made of poly(lactide-co-glycolide) (PLGA) nanoparticles containing azelaic acid for potential acne treatment.

METHODS

Azelaic acid-loaded PLGA nanoparticles were prepared by spontaneous emulsification processes using poloxamer 188 as stabilizer. Several manufacturing parameters such as stirring rate, concentration of stabilizer and different recovery methods were investigated. Nanoparticles were evaluated in terms of size, zeta potential, encapsulation efficiency, release kinetics and permeation kinetics in vitro. Furthermore, in vitro toxicological studies were performed in Saccharomyces cerevisiae model.

RESULTS

The results showed that by adjusting some formulation conditions it was possible to obtain nanoparticles with high loading and a controlled drug release. Freeze-dried recovery altered the nanoparticles structure by enhancing porous structures and mannitol was required to control the mean particle size. The centrifugation recovery was found to be the best approach to nanoparticles recovery. Similar toxicity profiles were observed for both drug-free and azelaic acid-loaded nanoparticles, with concentration-dependent decreases in cell viability.

CONCLUSION

These results indicate a potential formulation for controlled release delivery of azelaic acid to the follicular unit.

An experimental model of contact dermatitis: evaluation of the oxidative profile of Wistar rats treated with free and nanoencapsulated clobetasol

OBJECTIVE

An experimental animal model of contact dermatitis (CD) was used to investigate the effects of free and nanoencapsulated clobetasol propionate on the skin and on the oxidative profile of liver tissue.

METHODS

Female Wistar rats were divided into six groups, each containing eight rats. The first group, control (C), was sensitized with solid vaseline. Group 2, (CD), was sensitized with 5% NiSO(4). Groups 3 and 4 were sensitized with 5% NiSO(4) and treated with free (FC) and nanoencapsulated (NC) clobetasol (0.42 mg/g), respectively, daily for 5 days. Group 5 was treated with nanoencapsulated clobetasol (0.42 mg/g) on days 1, 3, and 5 (C135) and group 6 received a hydrogel containing empty nanoparticles (NP) daily for 5 days. Thiobarbituric acid reactive substances (TBARS), carbonyl levels, non-protein sulfhydryl groups (NPSH) and catalase activity were measured in liver homogenates.

RESULTS

A significant increase was observed in the levels of TBARS, NPSH, and catalase activity for the groups CD and NP.

DISCUSSION

Our results suggest that both NiSO(4) sensitization and NP administration induced oxidation of cellular lipids and activated the antioxidant enzyme catalase to protect from this damage. These results also indicated that daily treatment with the free and nanoencapsulated clobetasol, as well as treatment with the nanoencapsulated clobetasol every other day, were able to prevent these redox alterations and protect against histological damage.

Polymeric nanoparticles-based topical delivery systems for the treatment of dermatological diseases

Human skin not only functions as a permeation barrier (mainly because of the stratum corneum layer) but also provides a unique delivery pathway for therapeutic and other active agents. These compounds penetrate via intercellular, intracellular, and transappendageal routes, resulting in topical delivery (into skin strata) and transdermal delivery (to subcutaneous tissues and into the systemic circulation). Passive and active permeation enhancement methods have been widely applied to increase the cutaneous penetration. The pathology, pathogenesis, and topical treatment approaches of dermatological diseases, such as psoriasis, contact dermatitis, and skin cancer, are then discussed. Recent literature has demonstrated that nanoparticles-based topical delivery systems can be successful in treating these skin conditions. The studies are reviewed starting with the nanoparticles based on natural polymers especially chitosan, followed by those made of synthetic, degradable (aliphatic polyesters), and nondegradable (polyacrylates) polymers; emphasis is given to nanospheres made of polymers derived from naturally occurring metabolites, the tyrosine-derived nanospheres (TyroSpheres™). In summary, the nanoparticles-based topical delivery systems combine the advantages of both the nanosized drug carriers and the topical approach, and are promising for the treatment of skin diseases. For the perspectives, the penetration of ultra-small nanoparticles (size smaller than 40 nm) into skin strata, the targeted delivery of the encapsulated drugs to hair follicle stem cells, and the combination of nanoparticles and microneedle array technologies for special applications such as vaccine delivery are discussed.

Iron oxide nanoparticle-based magnetic resonance method to monitor release kinetics from polymeric particles with high resolution

A new method to precisely monitor rapid release kinetics from polymeric particles using super paramagnetic iron oxide nanoparticles, specifically by measuring spin-spin relaxation time (T(2)), is reported. Previously, we have published the formulation of logic gate particles from an acid-sensitive poly-β-aminoester ketal-2 polymer. Here, a series of poly-β-aminoester ketal-2 polymers with varying hydrophobicities were synthesized and used to formulate particles. We attempted to measure fluorescence of released Nile red to determine whether the structural adjustments could finely tune the release kinetics in the range of minutes to hours; however, this standard technique did not differentiate each release rate of our series. Thus, a new method based on encapsulation of iron oxide nanoparticles was developed, which enabled us to resolve the release kinetics of our particles. Moreover, the kinetics matched the relative hydrophobicity order determined by octanol-water partition coefficients. To the best of our knowledge, this method provides the highest resolution of release kinetics to date.

Development and evaluation of 5-fluorouracil loaded chitin nanogels for treatment of skin cancer

This study focuses on development and evaluation of 5-fluorouracil (5-FU) loaded chitin nanogels (FCNGs). It formed good, stable aqueous dispersion with spherical particles in 120-140 nm size range and showed pH responsive swelling and drug release. The FCNGs showed toxicity on melanoma (A375) in a concentration range of 0.4-2.0mg/mL, but less toxicity toward human dermal fibroblast (HDF) cells by MTT assay. Confocal analysis revealed uptake of FCNGs by both cells. From skin permeation experiments, FCNGs showed almost same steady state flux as that of control 5-FU but the retention in the deeper layers of skin was found to be 4-5 times more from FCNGs. Histopathological evaluation revealed loosening of the horny layer of epidermis by interaction of cationically charged chitin, with no observed signs of inflammation and so FCNGs can be a good option for treatment of skin cancers.

Microneedle-mediated vaccine delivery: harnessing cutaneous immunobiology to improve efficacy

INTRODUCTION

Breaching the skin's stratum corneum barrier raises the possibility of the administration of vaccines, gene vectors, antibodies and even nanoparticles, all of which have at least their initial effect on populations of skin cells.

AREAS COVERED

Intradermal vaccine delivery holds enormous potential for improved therapeutic outcomes for patients, particularly those in the developing world. Various vaccine-delivery strategies have been employed, which are discussed in this review. The importance of cutaneous immunobiology on the effect produced by microneedle-mediated intradermal vaccination is also discussed.

EXPERT OPINION

Microneedle-mediated vaccines hold enormous potential for patient benefit. However, in order for microneedle vaccine strategies to fulfill their potential, the proportion of an immune response that is due to the local action of delivered vaccines on skin antigen-presenting cells, and what is due to a systemic effect from vaccines reaching the systemic circulation, must be determined. Moreover, industry will need to invest significantly in new equipment and instrumentation in order to mass-produce microneedle vaccines consistently. Finally, microneedles will need to demonstrate consistent dose delivery across patient groups and match this to reliable immune responses before they will replace tried-and-tested needle-and-syringe-based approaches.

Assembling nanoparticle coatings to improve the drug delivery performance of lipid based colloids

Lipid based colloids (e.g. emulsions and liposomes) are widely used as drug delivery systems, but often suffer from physical instabilities and non-ideal drug encapsulation and delivery performance. We review the application of engineered nanoparticle layers at the interface of lipid colloids to improve their performance as drug delivery systems. In addition we focus on the creation of novel hybrid nanomaterials from nanoparticle-lipid colloid assemblies and their drug delivery applications. Specifically, nanoparticle layers can be engineered to enhance the physical stability of submicron lipid emulsions and liposomes, satbilise encapsulated active ingredients against chemical degradation, control molecular transport and improve the dermal and oral delivery characteristics, i.e. increase absorption, bioavailability and facilitate targeted delivery. It is feasible that hybrid nanomaterials composed of nanoparticles and colloidal lipids are effective encapsulation and delivery systems for both poorly soluble drugs and biological drugs and may form the basis for the next generation of medicines. Additional pre-clinical research including specific animal model studies are required to advance the peptide/protein delivery systems, whereas the silica lipid hybrid systems have now entered human clinical trials for poorly soluble drugs.

Skin permeating nanogel for the cutaneous co-delivery of two anti-inflammatory drugs

The aim of this study was to develop an effective drug delivery system for the simultaneous topical delivery of two anti-inflammatory drugs, spantide II (SP) and ketoprofen (KP). To achieve this primary goal, we have developed a skin permeating nanogel system (SPN) containing surface modified polymeric bilayered nanoparticles along with a gelling agent. Poly-(lactide-co-glycolic acid) and chitosan were used to prepare bilayered nanoparticles (NPS) and the surface was modified with oleic acid (NPSO). Hydroxypropyl methyl cellulose (HPMC) and Carbopol with the desired viscosity were utilized to prepare the nanogels. The nanogel system was further investigated for in vitro skin permeation, drug release and stability studies. Allergic contact dermatitis (ACD) and psoriatic plaque like model were used to assess the effectiveness of SPN. Dispersion of NPSO in HPMC (SPN) produced a stable and uniform dispersion. In vitro permeation studies revealed increase in deposition of SP for the SP-SPN or SP+KP-SPN in the epidermis and dermis by 8.5 and 9.5 folds, respectively than SP-gel. Further, the deposition of KP for KP-SPN or SP+KP-SPN in epidermis and dermis was 9.75 and 11.55 folds higher, respectively than KP-gel. Similarly the amount of KP permeated for KP-SPN or SP+KP-SPN was increased by 9.92 folds than KP-gel. The ear thickness in ACD model and the expression of IL-17 and IL-23; PASI score and TEWL values in psoriatic plaque like model were significantly less (p < 0.001) for SPN compared to control gel. Our results suggest that SP+KP-SPN have significant potential for the percutaneous delivery of SP and KP to the deeper skin layers for treatment of various skin inflammatory disorders.

Effect of oleic acid modified polymeric bilayered nanoparticles on percutaneous delivery of spantide II and ketoprofen

The objective of the present study was to evaluate the effect of oleic acid modified polymeric bilayered nanoparticles (NPS) on combined delivery of two anti-inflammatory drugs, spantide II (SP) and ketoprofen (KP) on the skin permeation. NPS were prepared using poly(lactic-co-glycolic acid) (PLGA) and chitosan. SP and KP were encapsulated in different layers alone or/and in combination (KP-NPS, SP-NPS and SP+KP-NPS). The surface of NPS was modified with oleic acid (OA) ('Nanoease' technology) using an established procedure in the laboratory (KP-NPS-OA, SP-NPS-OA and SP+KP-NPS-OA). Fluorescent dyes (DiO and DID) containing surface modified (DiO-NPS-OA and DID-NPS-OA) and unmodified NPS (DiO-NPS and DID-NPS) were visualized in lateral rat skin sections using confocal microscopy and Raman confocal spectroscopy after skin permeation. In vitro skin permeation was performed in dermatomed human skin and HPLC was used to analyze the drug levels in different skin layers. Further, allergic contact dermatitis (ACD) model was used to evaluate the response of KP-NPS, SP-NPS, SP+KP-NPS, KP-NPS-OA, SP-NPS-OA and SP+KP-NPS-OA treatment in C57BL/6 mice. The fluorescence from OA modified NPS was observed up to a depth of 240μm and was significantly higher as compared to non-modified NPS. The amount of SP and KP retained in skin layers from OA modified NPS increased by several folds compared to unmodified NPS and control solution. In addition, the combination index value calculated from ACD response for solution suggested an additive effect and moderate synergism for NPS-OA. Our results strongly suggest that surface modification of bilayered nanoparticles with oleic acid improved drug delivery to the deeper skin layers.

Hair dye-incorporated poly-γ-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation

Background

p-Phenylenediamine (PDA) or its related chemicals are used more extensively than oxidative hair dyes. However, permanent hair dyes such as PDA are known to have potent contact allergy reactions in humans, and severe allergic reactions are problematic.

Methods

PDA-incorporated nanoparticles were prepared based on ion-complex formation between the cationic groups of PDA and the anionic groups of poly(γ-glutamic acid) (PGA). To reinforce PDA/PGA ion complexes, glycol chitosan (GC) was added. PDA-incorporated nanoparticles were characterized using field-emission scanning electron microscopy, Fourier- transform infrared (FT-IR) spectroscopy, dynamic light scattering, and powder X-ray diffractometry (XRD).

Results

Nanoparticles were formed by ion-complex formation between the amine groups of PDA and the carboxyl groups of PGA. PDA-incorporated nanoparticles are small in size (<100 nm), and morphological observations showed spherical shapes. FT-IR spectra results showed that the carboxylic acid peak of PGA decreased with increasing PDA content, indicating that the ion complexes were formed between the carboxyl groups of PGA and the amine groups of PDA. Furthermore, the intrinsic peak of the carboxyl groups of PGA was also decreased by the addition of GC. Intrinsic crystalline peaks of PDA were observed by XRD. This crystalline peak of PDA was completely nonexistent when nanoparticles were formed by ion complex between PDA, PGA, and GC, indicating that PDA was complexed with PGA and no free drug existed in the formulation. During the drug-release experiment, an initial burst release of PDA was observed, and then PDA was continuously released over 1 week. Cytotoxicity testing against HaCaT human skin keratinocyte cells showed PDA-incorporated nanoparticles had lower toxicity than PDA itself. Furthermore, PDA-incorporated nanoparticles showed reduced apoptosis and necrosis reaction at HaCaT cells.

Conclusion

The authors suggest that these microparticles are ideal candidates for a vehicle for decreasing side effects of hair dye.

Stability of polylactic acid particles and release of fluorochromes upon topical application on human skin explants

Particle-based drug delivery systems allow the controlled and targeted release of incorporated active compounds to the skin and are promising tools to improve the efficacy of topical therapies. In this study we investigated the stability and release properties of biodegradable polylactic acid (PLA) particles upon topical application on human skin explants. PLA particles loaded with the hydrophilic fluorochrome 4-Di-2-Asp (DiAsp-PLA) were compared to PLA particles loaded with the lipophilic fluorochrome Bodipy 630/650 (BP-PLA). Changes of the particle morphology after their incubation on skin surface were investigated by means of electron microscopy while fluorescence microscopy and flow cytometry were used to evaluate particle penetration in hair follicles and fluorochrome release. We found that BP-PLA particles released rapidly the loaded fluorochrome and lost the particulate morphology within a few hours after application on skin surface. On the contrary, DiAsp-PLA particles maintained the particulate morphology, accumulated in hair follicles, and allowed a constant release of the incorporated fluorochrome for up to 16 h. These results show that, once applied to skin surface, PLA particles release the incorporated fluorochromes in a time-dependent manner and suggest the perspective to modulate particle stability and release properties by incorporating excipients with different degree of lipophilicity.

Nanoparticles in dermatology

Recent advances in the field of nanotechnology have allowed the manufacturing of elaborated nanometer-sized particles for various biomedical applications. A broad spectrum of particles, extending from various lipid nanostructures such as liposomes and solid lipid nanoparticles, to metal, nanocrystalline and polymer particles have already been tested as drug delivery systems in different animal models with remarkable results, promising an extensive commercialization in the coming years. Controlled drug release to skin and skin appendages, targeting of hair follicle-specific cell populations, transcutaneous vaccination and transdermal gene therapy are only a few of these new applications. Carrier systems of the new generation take advantage of improved skin penetration properties, depot effect with sustained drug release and of surface functionalization (e.g., the binding to specific ligands) allowing specific cellular and subcellular targeting. Drug delivery to skin by means of microparticles and nanocarriers could revolutionize the treatment of several skin disorders. However, the toxicological and environmental safety of micro- and nanoparticles has to be evaluated using specific toxicological studies prior to a wider implementation of the new technology. This review aims to give an overview of the most investigated applications of transcutaneously applied particle-based formulations in the fields of cosmetics and dermatology.

Nanoparticles and their interactions with the dermal barrier

The dermal application of drugs is promising due to the ease of application. In this context nano-scale carrier systems were already evaluated in several studies with respect to the skin interaction and the impact on drug penetration. At the same time the upcoming production of engineered nano-scale materials requires a thorough safety evaluation. Drug delivery as well as risk assessment depends crucially on the ability of such carriers to overcome the skin barrier and reach deeper tissue layers. Therefore, the interaction of nanoparticles with skin and especially skin models is an intriguing field. However, the data obtained do not show a clear image on the effect of nano-carriers. Especially the penetration of such particles is an open and controversially discussed topic. The literature reports different results mainly on pig or murine skin showing strong penetration (pig and mouse) or the opposite. Looking only at the sizes of the particles also no conclusive picture can be obtained. Nevertheless, size is regarded to play an important role for skin penetration. Furthermore, the state of the skin influences penetration (hydration) and the mechanical stress is of outmost importance.