ImprovedIn vitroandIn vivoCutaneous Delivery of Protoporphyrin IX from PLGA-based Nanoparticles

Antimicrobial Photodynamic Therapy Using Encapsulated Protoporphyrin IX for the Treatment of Bacterial Pathogens

Herein, we report on the antimicrobial photodynamic effect of polymeric nanoparticles containing the endogenous photosensitizer protoporphyrin IX. Compared to equivalent doses of the free photosensitizer, we demonstrated that the photodynamic antimicrobial efficacy of PLGA (polylactic-co-glycolic acid) nanoparticles containing protoporphyrin IX (PpIX) against pathogenic Staphylococcus aureus (S. aureus) is preserved after encapsulation, while photobleaching is reduced. In addition, compared to equivalent doses of the free porphyrin, we show that a reduction in the cytotoxicity in mammalian cell cultures is observed when encapsulated. Therefore, the encapsulation of protoporphyrin IX reduces its photodegradation, while the released photosensitizer maintains its ability to generate reactive oxygen species upon light irradiation. The polymeric nanoencapsulation promotes aqueous solubility for the hydrophobic PpIX, improves its photostability and reduces the cytotoxicity, while providing an extended release of this endogenous photosensitizer.

Multi-charged nanoemulsion for photodynamic treatment of glioblastoma cell line in 2D and 3D in vitro models

Multi-charged nanoemulsions (NE) were designed to deliver Cannabidiol (CBD), Indocyanine green (ICG), and Protoporphyrin (PpIX) to treat glioblastoma (GBM) through Photodynamic Therapy (PDT). The phase-inversion temperature (PIT) method resulted in a highly stable NE that can be scaled easily, with a six-month shelf-life. We observed the quasi-spherical morphology of the nanoemulsions without any unencapsulated material and that 89% (± 5.5%) of the material was encapsulated. All physicochemical properties were within the expected range for a nanostructured drug delivery system, making these multi-charged nanoemulsions promising for further research and development. NE-PIC (NE-Protoporphyrin + Indocyanine + CBD) was easily internalized on GBM cells after three hours of incubation. Nanoemulsion (NE and NE-PIC) did not result in significant cytotoxicity, even for GBM or non-tumorigenic cell lines (NHF). Phototoxicity was significantly higher for the U87MG cell than the T98G cell when exposed to: visible (430 nm) and infrared (810 nm) laser light, with a difference of about 20%. From 50 mJ.cm-2, the viability of GBM cell lines decreases significantly, ranging from 65% to 85%. The NE-PIC was also effective for inhibiting cell proliferation into a 3D spheroidal GBM cell model, which is promising for mimicking the tumor cell environment. Irradiation at 810 nm was more effective in treating spheroid due to its deeper penetration in complex structures. NE-PIC has the potential as a drug delivery system for photoinactivation and photo diagnostic of GBM cell lines, taking advantage of the versatility of its active components.

Polymeric Nanoparticles as Tunable Nanocarriers for Targeted Delivery of Drugs to Skin Tissues for Treatment of Topical Skin Diseases

The topical route is the most appropriate route for the targeted delivery of drugs to skin tissues for the treatment of local skin diseases; however, the stratum corneum (SC), the foremost layer of the skin, acts as a major barrier. Numerous passive and active drug delivery techniques have been exploited to overcome this barrier; however, these modalities are associated with several detrimental effects which restrict their clinical applicability. Alternatively, nanotechnology-aided interventions have been extensively investigated for the topical administration of a wide range of therapeutics. In this review, we have mainly focused on the biopharmaceutical significance of polymeric nanoparticles (PNPs) (made from natural polymers) for the treatment of various topical skin diseases such as psoriasis, atopic dermatitis (AD), skin infection, skin cancer, acute-to-chronic wounds, and acne. The encapsulation of drug(s) into the inner core or adsorption onto the shell of PNPs has shown a marked improvement in their physicochemical properties, avoiding premature degradation and controlling the release kinetics, permeation through the SC, and retention in the skin layers. Furthermore, functionalization techniques such as PEGylation, conjugation with targeting ligand, and pH/thermo-responsiveness have shown further success in optimizing the therapeutic efficacy of PNPs for the treatment of skin diseases. Despite enormous progress in the development of PNPs, their clinical translation is still lacking, which could be a potential future perspective for researchers working in this field.

Mesoporous Silica-Coated Upconversion Nanoparticles Assisted Photodynamic Therapy Using 5-Aminolevulinic Acid: Mechanistic and In Vivo Studies

Exclusively red-emitting upconversion nanoparticles (UCNPs) with the composition NaErF₄:0.5%Tm as a core and NaYF₄ as a shell were synthesized for performing photodynamic therapy (PDT). A possible mechanism was proposed for core-shell UCNPs formation. For loading a maximum amount of 5-aminolevulinic acid (5-ALA), mesoporous silica coating was performed on UCNPs. Studies under dark conditions confirmed the biocompatibility of 5-ALA-loaded UCNPs formulation (UCNPs-5-ALA) with MCF-7 cells. Meanwhile, studies under light-exposed conditions exhibited effective cytotoxicity against MCF-7 cells. Studies employing D₂O-based cell cultured media and addition of DABCO in cell culture established that the cell death was due to oxidation of cellular components by reactive oxygen species (ROS) triggering the apoptosis. The formation of ROS was confirmed by DCF(H)DA-based ROS analysis via fluorescence microscopy to demonstrate the ROS production, which mediates the programmed cell death. Additionally, we have validated the apoptosis in MCF-7 cells with flow cytometry analyses. This was further confirmed by an electrophoretic mobility shift assay on nuclear extract and measurement of mitochondrial membrane potential. In the case of animal model studies, the formulation UCNPs-5-ALA without irradiation (980 nm) did not possess any in vivo cytotoxicity on tumor-induced SCID mice and there was a minimum migration of UCNPs-5-ALA to the vital organs but maximum retention at the tumor site only. Meanwhile, only the mice treated with UCNPs-5-ALA and irradiated on the tumor region with 980 nm laser (500 mW) for 20 min possessed a tumor with a size reduced to about 75% as compared with the corresponding control groups. To the best of our knowledge, this type of study was conducted for the first time employing exclusively red-emitting phosphors for effective PDT.

Nanocarriers for Photodynamic Therapy Intended to Cutaneous Tumors

Photodynamic Therapy (PDT) is a therapeutic modality used for several malignant and premalignant skin disorders, including Bowen's disease skin cancers and Superficial Basal Cell Carcinoma (BCC). Several photosensitizers (PSs) have been explored for tumor destruction of skin cancers, after their activation by a light source of appropriate wavelength. Topical release of PSs avoids prolonged photosensitization reactions associated with systemic administration; however, its clinical usefulness is influenced by its poor tissue penetration and the stability of the active agent. Nanotechnology-based drug delivery systems are promising tool to enhance the efficiency for PDT of cancer. This review focuses on PSs encapsulated in nanocarriers explored for PDT of skin tumors.

Protoporphyrin IX (PpIX) loaded PLGA nanoparticles for topical Photodynamic Therapy of melanoma cells

INTRODUCTION

Nanoparticles (Np) can increase drug efficacy and overcome problems associated with solubility and aggregation in a solution of PpIX.

PURPOSE

Evaluate if Np interferes in the photophysical and photobiological capacity of the PpIX comparing with free PpIX intended for topical PDT of melanoma.

METHODS

In vitro photophysical evaluation of Np-PpIX was carried out through singlet oxygen (₁O²) quantum yield. In vitro cytotoxicity and phototoxicity assays have used murine melanoma cell culture.

RESULTS

The quantum yield of singlet oxygen has shown that Np did not influence the formation capacity of this reactive species. In the dark, all PpIX-Nps concentrations were less cytotoxic compared to free drugs. At a higher light dose (1500 mJ.cm²) 3.91 μg / mL PpIX had similar % viable cells for free and Np (∼34 %) meaning Nps did not interfere in the photodynamic effect of PpIX. However, at 7.91 μg / mL the phototoxicity increased for both (5.8 % viable cells for free versus 21.7 % for Nps). Despite the higher phototoxicity of free PpIX at this concentration, greater cytotoxicity in the dark was obtained (∼49 % viable cells for free versus ∼90.6 % Np) which means Nps protect the tumor tissue from the photodynamic action of PpIX.

CONCLUSIONS

Np is a potential delivery system for melanoma skin cancer, since it maintained the photophysical properties of PpIX and excellent in vitro phototoxicity effect against melanoma cells, reducing cell viability ∼80 % (7.91 μg / mL PpIX in Nps) and provides safe PDT (due to lower cytotoxicity in the dark).

Oleic Acid Vesicles as a new Approach for Transdermal Delivery of Econazole Nitrate: Development, Characterization, and In-vivo Evaluation in Wistar rats

BACKGROUND

Cutaneous candidiasis is a deep-seated skin fungal infection that is most commonly observed in immunocompromised patients. This fungal infection is conventionally treated with various formulations like gels and creams which are having different side effects and least therapeutic efficacy. Hence, it becomes necessary to develop a novel carrier system for the treatment of this deep-seated skin fungal infection. Econazole nitrate is the most widely used antifungal for the treatment of cutaneous candidiasis, therefore, in present research work we developed and evaluated econazole nitrate loaded oleic acid vesicles for treatment of cutaneous candidiasis through transdermal route.

METHODS

Econazole nitrate loaded oleic acid vesicles were prepared by thin-film hydration and characterized for drug entrapment, vesicle size, zeta potential, polydispersity index (PDI), Fourier Transform-infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) analysis. Furthermore, the oleic acid vesicular gel was evaluated for ex-vivo skin permeation/retention and in-vitro and in-vivo antifungal activity in Wistar rats.

RESULTS

Econazole nitrate loaded oleic acid vesicles showed high encapsulation of drug (74.76 ± 3.0%), acceptable size (373.4 ± 2.9 nm), and colloidal characteristics (PDI = 0.231 ± 0.078, zeta potential = -13.27 ± 0.80 mV). The oleic acid vesicular gel showed high skin permeation (Transdermal flux = 61.98 ± 2.45 μg/cm2/h), skin retention (35.90 ± 2.06%), in-vitro, and in-vivo antifungal activity compared to marketed cream (EcodermR) of econazole nitrate for a prolonged period of time (4 days).

CONCLUSION

Developed econazole nitrate loaded oleic acid vesicles could be used effectively in the treatment of cutaneous candidiasis with minimization of side effects of econazole nitrate with increased therapeutic efficacy.

In vitro Studies of Antitumor Effect, Toxicity/Cytotoxicity and Skin Permeation/Retention of a Green Fluorescence Pyrene-based Dye for PDT Application

Photosensitizers (PS) are compounds that can generate reactive oxygen species under irradiation of appropriate light and are widely used in photodynamic therapy (PDT). Currently, topical PDT is an effective treatment for several skin diseases, including bacterial infections, fungal mycoses and psoriasis. In addition, PDT is also used to treat nonmelanoma skin cancer and can be a potential tool for melanoma, associated with other treatments. In this work, we evaluated the antitumor photoactivity of a new pyrene-based PS (TPPy) by using the murine melanoma cell line (B16F10). The in vitro permeation/retention tests in porcine ear skin were also performed in order to evaluate the potential application of the PS for topical use in skin cancer. Moreover, to determine the toxicity in vivo, we used the Galleria mellonella as an alternative animal model of study. The results showed that TPPy is a promising PS for application in PDT, with potential antitumor photoactivity (IC₅₀ 6.5 μmol L^-1 ), absence of toxicity in the G. mellonella model at higher concentration (70.0 mmol L^-1 ) and the accumulation tendency in the epidermis plus dermis sites (165.20 ± 4.12 ng cm^-2 ).

Recent Progress in the Development of Poly(lactic-co-glycolic acid)-Based Nanostructures for Cancer Imaging and Therapy

Diverse nanosystems for use in cancer imaging and therapy have been designed and their clinical applications have been assessed. Among a variety of materials available to fabricate nanosystems, poly(lactic-co-glycolic acid) (PLGA) has been widely used due to its biocompatibility and biodegradability. In order to provide tumor-targeting and diagnostic properties, PLGA or PLGA nanoparticles (NPs) can be modified with other functional materials. Hydrophobic or hydrophilic therapeutic cargos can be placed in the internal space or adsorbed onto the surface of PLGA NPs. Protocols for the fabrication of PLGA-based NPs for cancer imaging and therapy are already well established. Moreover, the biocompatibility and biodegradability of PLGA may elevate its feasibility for clinical application in injection formulations. Size-controlled NP’s properties and ligand–receptor interactions may provide passive and active tumor-targeting abilities, respectively, after intravenous administration. Additionally, the introduction of several imaging modalities to PLGA-based NPs can enable drug delivery guided by in vivo imaging. Versatile platform technology of PLGA-based NPs can be applied to the delivery of small chemicals, peptides, proteins, and nucleic acids for use in cancer therapy. This review describes recent findings and insights into the development of tumor-targeted PLGA-based NPs for use of cancer imaging and therapy.

Copaiba oil enhances in vitro/in vivo cutaneous permeability and in vivo anti-inflammatory effect of celecoxib

OBJECTIVES

The aim of this article was to use copaiba oil (C.O) to improve skin permeability and topical anti-inflammatory activity of celecoxib (Cxb).

METHODS

Formulations containing C.O (1-50%) were associated with Cxb (2%). In vitro skin permeability studies were conducted using porcine ear skin. Histological analysis of the hairless mice skin samples after application of formulations was achieved with the routine haematoxylin/eosin technique. The anti-inflammatory activity was assessed using the AA-induced ear oedema mice model.

KEY FINDINGS

The formulation containing 25% C.O promoted the highest levels of in vitro Cxb permeation through pig ear skin, retention in the stratum corneum (SC) and epidermis/dermis of pig ear skin in vitro (~5-fold) and hairless mice skin in vivo (~2.0-fold), as compared with the control formulation. At 25%, C.O caused SC disorganization and increased cell infiltration and induced angiogenesis without clear signs of skin irritation. The formulation added to 25% C.O as adjuvant inhibited ear oedema and protein extravasation by 77.51 and 89.7%, respectively, and that it was, respectively, 2.0- and 3.4-fold more efficient than the commercial diethylammonium diclofenac cream gel to suppress these inflammatory parameters.

CONCLUSIONS

25% C.O is a potential penetration enhancer for lipophilic drugs like Cxb that can improve cutaneous drug penetration and its anti-inflammatory activity.

Strategies for optimizing the delivery to tumors of macrocyclic photosensitizers used in photodynamic therapy (PDT)

This review briefly summaries the principles and mechanisms of action of photodynamic therapy (PDT) as concerns its application in the oncological field, highlighting its drawbacks and some of the strategies that have been or are being explored to overcome them. The major aim is to increase the efficiency and selectivity of the photosensitizer (PS) uptake in the cancer cells for optimizing the PDT effects on tumors while sparing normal cells. Some attempts to achieve this are based on the conjugation of the PS to biomolecules (small ligands, peptides) functioning as carriers with the ability to efficiently penetrate cells and/or specifically recognize and bind proteins/receptors overexpressed on the surface of cancer cells. Alternatively, the PS can be entrapped in nanocarriers derived from various types of materials that can target the tumor by exploiting the enhanced permeability and retention (EPR) effects. The use of nanocarriers is particularly attractive because it allows the simultaneous delivery of more than one drug with the possibility of combining PDT with other therapeutic modalities.

Optimization of protoporphyrin IX skin delivery for topical photodynamic therapy: Nanodispersions of liquid-crystalline phase as nanocarriers

Nanodispersions of liquid-crystalline phases (NLPs) composed of monoolein and oleic acid were chosen as nanocarriers to improve the topical retention of the photosensitizer protoporphyrin IX (PpIX) and thereby optimize photodynamic therapy (PDT) using this photosensitizer. The nanodispersions were characterized by polarized light microscopy, small-angle X-ray diffraction and dynamic light scattering. The stability and encapsulation efficiency (EE%) of the nanodispersions were also evaluated. In vitro and in vivo skin penetration studies were performed to determine the potential of the nanodispersions for cutaneous application. In addition, skin penetration and skin irritancy (in an animal model) after in vivo application were visualized by fluorescence light microscopy. The nanodispersion obtained was characterized as a monodisperse system (~150.0 nm) of hexagonal liquid-crystalline phase, which provided a high encapsulation efficiency of PpIX (~88%) that remained stable over 90 days of investigation. Skin penetration studies demonstrated that the nanodispersion enhanced PpIX skin uptake 11.8- and 3.3-fold (in vitro) and 23.6- and 20.8-fold (in vivo) compared to the PpIX skin uptake of control formulations, respectively. In addition, the hexagonal phase nanodispersion did not cause skin irritation after application for two consecutive days. Overall, the results show that the nanocarrier developed is suitable for use in topical PDT with PpIX.

Targeted delivery of 5-aminolevulinic acid by multifunctional hollow mesoporous silica nanoparticles for photodynamic skin cancer therapy

5-Aminolevulinic acid (5-ALA) is a precursor of a strong photosensitizer, protoporphyrin IX (PphIX), for photodynamic therapy (PDT). Developing appropriate delivery carriers that can assist 5-ALA in bypassing the lipophilic barrier to directly enter into cancer cells is a research focus. The improved delivery of 5-ALA is even important for skin cancer therapy through PDT process. In this work, targeting ligand folic acid (FA)-functionalized hollow mesoporous silica nanoparticles (HMSNPs) were fabricated to deliver 5-ALA for PDT against B16F10 skin cancer cells. The FA targeting ligand enabled selective endocytosis of 5-ALA loaded HMSNPs into cancer cells. PphIX formed from delivered 5-ALA exhibited high photocytotoxicity to the cancer cells in vitro.

Computer modeling of the complexes of Chlorin e6 with amphiphilic polymers

Recently it has been shown that Chlorin e6 (Ce6) when complexed with Pluronics (hydrophilic ethylene and propylene oxide block copolymers) and poly(N-vinylpyrrolidone) (PVP) exhibits considerably higher phototoxicity towards tumor cells than free Ce6. The present work aimed to model Ce6 interactions with hydrophilic Pluronic F127 and PVP and find out the nature of intermolecular forces stabilizing these complexes. Modeling included 3 steps: (i) application of molecular dynamics to study polymer folding using AMBER 8 program, (ii) evaluation of partial charges in the Ce6 molecule using different quantum mechanical, semi-empirical and topological approaches and (iii) docking analysis of Ce6 interactions with polymer coils using AUTODOCK 4.2. It was found that the folding in regular polymers does not occur stochastically, but involves the formation of "primary" helical structures, which further combined to form hairpin-like "secondary" structures. The latter in turn associated to form coils with minimal solvent accessible hydrophobic area. The Ce6 ring lies flat on the surface of the polymer coil at the interface between hydrophobic and hydrophilic regions. Calculations showed higher affinity of Ce6 for PVP in comparison to Pluronic and revealed marginal contribution of Coulomb forces to the stabilization of both complexes, which are mainly stabilized by van der Waals and hydrogen interactions.

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.

Preparation and evaluation of hypocrellin A loaded poly(lactic-co-glycolic acid) nanoparticles for photodynamic therapy

The PLGA/HA NPs showed improved dispersibility and enhanced photostability, while maintaining high phototoxicity and ROS production ability.