Cineole-containing nanoemulsion: Development, stability, and antibacterial activity.

1,8-cineole is a monoterpene commonly used by the food, cosmetic, and pharmaceutical industries owing to its flavor and fragrances properties. In addition, this bioactive monoterpene has demonstrated bactericidal and fungicidal activities. However, such activities are limited due to its low aqueous solubility and stability. This study aimed to develop nanoemulsion containing cineole and assess its stability and antibacterial activity in this context. The spontaneous emulsification method was used to prepare nanoemulsion (NE) formulations (F1, F2, F3, F4, and F5). Following the development of NE formulations, we chose the F1 formulation that presented an average droplet size (in diameter) of about 100 nm with narrow size distribution (PdI <0.2) and negative zeta potential (∼ - 35 mV). According to the analytical centrifugation method with photometric detection, F1 and F5 formulations were considered the most stable NE with lower droplet migration velocities. In addition, F1 formulation showed high incorporation efficiency (> 80 %) and TEM analyses demonstrated nanosized oil droplets with irregular spherical shapes and without any aggregation tendency. Antibacterial activity assessment showed that F1 NE was able to enhance the cineole action against Staphylococcus aureus, Enterococcus faecalis, and Streptococcus pyogenes. Therefore, using a simple and reproducible method of low energy emulsification we designed a stable nanoemulsion containing 1,8-cineole with improved antibacterial activity against Gram-positive strains.

Anthraquinone encapsulation into polymeric nanocapsules as a new drug from biotechnological origin designed for photodynamic therapy.

Photodynamic therapy has been applied for the treatment of many diseases, especially skin diseases. However, poor aqueous solubility and toxicity of some photosensitizer drugs are the main disadvantages for their direct clinical applications. Thus, biotechnology and nanotechnology are important tools in the development of new ways of obtaining photoactive compounds that are biocompatible. We investigated the potential of a new nanostructured photosensitizer, an anthraquinone derivative produced by biotechnological process; then we associated nanotechnology to obtain a nanostructured anthraquinone active molecule. For this, it was prepared a classical nanocapsule formulations containing poly(lactide-co-glycolide) (PLGA) coating for encapsulation of anthraquinone derivative. These formulations were characterized by their physicochemical, morphological, photophysical properties, and stability. We performed in vitro biocompatibility and photodynamic activity assays of free and nanostructured anthraquinone. Nanocapsule formulations containing anthraquinone derivative showed a nanometric profile with particle size around 250 nm, negative zeta potential around -30 mV, and partially monodisperse. Besides that, characteristic spherical morphology of nanocapsules and homogeneous particle surface were observed by AFM analyses. The in vitro biocompatibility assay showed absence of cytotoxicity for all tested RD/NC concentrations and also for unloaded/NC in NIH3T3 cells. In vitro photoactivation assay using NIH3T3 cells showed that nanocapsules promoted greater drug uptake by NIH3T3 cells, around of 87%, of cell death compared to free drug showed around 48% of cell death. The anthraquinone derivative showed potential for use in PDT. Besides the association with nanocapsules improved cell uptake of photosensitizer resulting in increased cell death compared to free anthraquinone.

Application of aluminum chloride phthalocyanine-loaded solid lipid nanoparticles for photodynamic inactivation of melanoma cells.

Cutaneous melanoma is the most aggressive skin cancer and is particularly resistant to current therapeutic approaches. Photodynamic therapy (PDT) is a well-established photoprocess that is employed to treat some cancers, including non-melanoma skin cancer. Aluminum chloride phthalocyanine (ClAlPc) is used as a photosensitizer in PDT; however, its high hydrophobicity hampers its photodynamic activity under physiological conditions. The aim of this study was to produce solid lipid nanoparticles (SLN) containing ClAlPc using the direct emulsification method. ClAlPc-loaded SLNs (ClAlPc/SLNs) were characterized according to their particle size and distribution, zeta potential, morphology, encapsulation efficiency, stability, and phototoxic action in vitro in B16-F10 melanoma cells. ClAlPc/SLN had a mean diameter between 100 and 200nm, homogeneous size distribution (polydispersity index <0.3), negative zeta potential, and spherical morphology. The encapsulation efficiency was approximately 100%. The lipid crystallinity was investigated using X-ray diffraction and differential scanning calorimetry and indicated that ClAlPc was integrated into the SLN matrix. The ClAlPc/SLN formulations maintained their physicochemical stability without expelling the drug over a 24-month period. Compared to free ClAlPc, ClAlPc/SLN exerted outstanding phototoxicity effects in vitro against melanoma cells. Therefore, our results demonstrated that the ClAlPc/SLN described in the current study has the potential for use in further preclinical and clinical trials in PDT for melanoma treatment.

Development, characterization, and photocytotoxicity assessment on human melanoma of chloroaluminum phthalocyanine nanocapsules.

In this work we have developed nanocapsules containing chloroaluminum phthalocyanine (ClAlPc) and assessed their phototoxic action on WM1552C, WM278, and WM1617 human melanoma cell lines. The ClAlPc-loaded nanocapsules were prepared by the nanoprecipitation method and optimized by means of a 2(3) full factorial design. The ClAlPc nanocapsules were characterized by particle size and distribution, zeta potential, morphology, encapsulation efficiency, singlet oxygen production, stability, and phototoxic action on melanoma cells. Both the development and optimization studies revealed that stable colloidal formulations could be obtained by using 1.75% (w/v) soybean lecithin, 1.25% (w/v) Poloxamer 188, 2.5% (v/v) soybean oil, and 0.75% (w/v) poly(D,L-lactide-co-glycolide). The nanocapsules had a mean diameter of 230 nm, homogeneous size distribution (polydispersity index<0.3), and negative zeta potential (about -30 mV). Their morphology was spherical, with evident polymer membrane coating droplet. The encapsulation efficiency was 70%, as expected for hydrophobic drugs, and the nanoencapsulated ClAlPc was able to produce high singlet oxygen quantum yield. ClAlPc nanocapsules exhibited good physical stability over a 12-month period. WM1552C primary melanoma cells were more sensitive (p<0.05) to the phototoxic effect elicited by ClAlPc nanocapsules (0.3 µg ml(-1)) under light irradiation at 20 mJ cm(-2). On the other hand, the cell survival percentage for all the melanoma cell lines treated with the highest light dose (150 mJ cm(-2)) was lower than 10%. In summary, ClAlPc nanoencapsulation could enable application of this hydrophobic photosensitizer in the treatment of malignant melanoma with the use of both low sensitizer drug concentration and light dose.

Gelled oil particles: a new approach to encapsulate a hydrophobic metallophthalocyanine.

Chloroaluminum phthalocyanine (ClAlPc) is a promising sensitizer molecule for photodynamic therapy, but its hydrophobicity makes it difficult to formulate. In this study, we have efficiently encapsulated ClAlPc into gelled soybean oil particles dispersed in water. 12-Hydroxystearic acid (HSA) and polyethyleneimine (PEI) were the gelling and stabilizing agents, respectively. The preparation process involved hot emulsification above the gelation temperature (Tgel), followed by cooling to room temperature, which gave a colloidal dispersion of gelled particles of oil in aqueous medium. The gelled particles containing ClAlPc had a medium diameter of 280 nm, homogeneous size distribution (polydispersity index ≈0.3) and large positive zeta potential (about +50 mV) and showed a spherical morphology. The gelled oil particle formulations exhibited good physical stability over a 6-month period. ClAlPc interfered with the HSA self-assembly only slightly, and decreased the gelation temperature to a small extent; however it did not affect gelation process of the oil droplets. The amounts of PEI and HSA employed during the preparation allowed us to control particle size and the dispersion stability, a phenomenon that results from complex electrostatic interactions between the positively charged PEI and the negatively charged HSA fibers present on the gelled particles surface. In summary, by using the right ClAlPc, HSA, and PEI proportions, we prepared very stable dispersions of gelled soybean oil particles with excellent ClAlPc encapsulation efficiency. The obtained colloidal formulation of gelled oil particles loaded with ClAlPc shall be very useful for photodynamic therapy protocols.

In vitro evaluation of combined hyperthermia and photodynamic effects using magnetoliposomes loaded with cucurbituril zinc phthalocyanine complex on melanoma.

The aims of this study were two fold; to develop magnetoliposomes (MLs) loaded with zinc phthalocyanine (ZnPc) complexed with cucurbituril (CB) (CB:ZnPc-MLs) and to evaluate their in vitro photodynamic (PD) and/or hyperthermia (HT) effects while using melanoma cells (B16-F10) as model. The liposomal formulations were characterized by both average diameter and zeta potential. The vesicle average size ranged from 150 to 200 nm and the polydispersity index (PdI) from 0.093 to 0.230. The zeta potential was significantly positive with values between 48 and 57 mV. The cell viability (CV) after PD and HT treatments was assessed by colorimetric MTT method. Melanoma cells were initially treated with the liposome formulation without light and magnetic field application, revealing cell viability not different from the control cells (p>0.05). Photodynamic and hyperthermia assays were also applied separately, demonstrating that PD is more effective than HT in reducing the CV of the neoplastic cells. Combined application of both PD and HT treatments was even more effective in reducing the CV of B16-F10 cells. At the highest light dose (2 J/cm(2)) and under magnetic field activation the CV was about half than PD applied alone. Therefore, the use of the photosensitizer-loaded magnetoliposome for combined photodynamic therapy (PDT) and magnetohyperthermia (MHT) application can be considered as a potential tool to treat malignant melanoma.

In vitro antifungal activity and toxicity of itraconazole in DMSA-PLGA nanoparticles.

Itraconazole (ITZ) is a drug used to treat various fungal infections and may cause side effects. The aim of this study was to develop and evaluate the in vitro activity of DMSA-PLGA nanoparticles loaded with ITZ against Paracoccidioides brasiliensis, as well as their cytotoxicity. Nanoparticles were prepared using the emulsification-evaporation technique and characterized by their encapsulation efficiency, morphology (TEM), size (Nanosight) and charge (zeta potential). Antifungal efficacy in P. brasiliensis was determined by minimal inhibition concentration (MIC), and cytotoxicity using MTT assay. ITZ was effectively incorporated in the PLGA-DMSA nanoparticles with a loading efficiency of 72.8 +/- 3.50%. The shape was round with a solid polymeric structure, and a size distribution of 174 +/- 86 nm (Average +/- SD). The particles were negatively charged. ITZ-NANO presented antifungal inhibition (MIC = 6.25 ug/mL) against P. brasiliensis and showed lower in vitro cytotoxicity than free drug (ITZ).

In vitro phototoxicity of liposomes and nanocapsules containing chloroaluminum phthalocyanine on human melanoma cell line.

In this study, the photodynamic action of liposomes (LP) and nanocapsules (NC) containing Chloroaluminum phthalocyanine (CIAIPc), on the human melanoma cell (WM 1552C), was assessed. The light source was setup at 672 nm, which corresponds to the maximum absorption wavelength of the CIAIPc. Both colloidal carriers presented size in nanometric scale as well as negative zeta potential. The cellular damage was light dose dependent ranging from 30% of cell death at 70 mJ x cm-2 to 90% of death at 700 mJ x cm(-2). However, the photocytotoxic effect of LP at 70 mJ x cm(-2) was slightly more efficient to induce cellular death than NC formulation. At 140 mJ x cm(-2), and 700 mJ x cm(-2) both nanocarriers were equally efficient to induce cellular damage. Therefore, in the present work, the maximum phototoxic effect was obtained with 700 mJ x cm(-2) of light dose, in combination with 0.29 microg x mL(-1) of CIAIPc encapsulated into LP and NC. The cells were also positive to annexin V, after the PDT treatment with LP and NC, showing that one of the mechanisms of cellular death involved is apoptosis. In summary, the potential of LP and NC as a drug delivery system, in Photodynamic Therapy (PDT) against melanoma, has been confirmed using a lower concentration of the photosensitizer and lower light doses than that applied in current protocols. This is an innovative proposal to treat melanoma cell lines that until now have not received the benefit of the PDT protocol for treatment.

In vitrouptake and antimycobacterial activity of liposomal usnic acid formulation.

The cellular uptake and antimycobacterial activity of usnic acid (UA) and usnic acid-loaded liposomes (UA-LIPOs) were assessed on J774 macrophages. The minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) of UA and UA-LIPO against Mycobacterium tuberculosis were determined. Concentrations required to inhibit 50% of cell proliferation (IC(50)) were 22.5 (+/-0.60) and 12.5 (+/-0.26) microg/ml, for UA and UA-LIPO, respectively. The MICs of UA and UA-LIPO were 6.5 and 5.8 microg/mL, respectively. The MBC of UA-LIPO was twice as low (16 microg/mL) as that of UA (32 microg/mL). An improvement in the intracellular uptake of UA-LIPO was found (21.6 x 10(4) +/- 28.3 x 10(2) c.p.s), in comparison with UA (9.5 x 10(4) +/- 11.4 x 10(2) c.p.s). In addition, UA-LIPO remains much longer inside macrophages (30 hours). All data obtained from the encapsulation of usnic acid into liposomes as a drug delivery system (DDS) indicate a strong interaction between UA-liposomes and J774 macrophages, thereby facilitating UA penetration into cells. Considering such a process as ruling the Mycobacterium-transfection by magrophages, we could state that associating UA with this DDS leads to an improvement in its antimycobacterial activity.