Amílcar Roberto

Polymeric nanoparticles modified with fatty acids encapsulating betamethasone for anti-inflammatory treatment.

Topical glucocorticosteroids were incorporated into nanocarrier-based formulations, to overcome side effects of conventional formulations and to achieve maximum skin deposition. Nanoparticulate carriers have the potential to prolong the anti-inflammatory effect and provide higher local concentration of drugs, offering a better solution for treating dermatological conditions and improving patient compliance. Nanoparticles were formulated with poly-ϵ-caprolactone as the polymeric core along with stearic acid as the fatty acid, for incorporation of betamethasone-21-acetate. Oleic acid was applied as the coating fatty acid. Improvement of the drug efficacy, and reduction in drug degradation with time in the encapsulated form was examined, while administering it locally through controlled release. Nanoparticles were spherical with mean size of 300 nm and negatively charged surface. Encapsulation efficiency was 90%. Physicochemical stability in aqueous media of the empty and loaded nanoparticles was evaluated for six months. Drug degradation was reduced compared to free drug, after encapsulation into nanoparticles, avoiding the potency decline and promoting a controlled drug release over one month. Fourier transform infrared spectroscopy and thermal analysis confirmed drug entrapment, while cytotoxicity studies performed in vitro on human keratinocytes, Saccharomyces cerevisiae models and Artemia salina, showed a dose-response relationship for nanoparticles and free drug. In all models, drug loaded nanoparticles had a greater inhibitory effect. Nanoparticles increased drug permeation into lipid membranes in vitro. Preliminary safety and permeation studies conducted on rats, showed betamethasone-21-acetate in serum after 48 h application of a gel containing nanoparticles. No skin reactions were observed. In conclusion, the developed nanoparticles may be applied as topical treatment, after encapsulation of betamethasone-21-acetate, as nanoparticles promote prolonged drug release, increase drug stability in aqueous media, reducing drug degradation, and increase drug permeability through lipid membranes.

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

Abstract 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.

Design of Finasteride-Loaded Nanoparticles for Potential Treatment of Alopecia

Background/Aims: Androgenetic alopecia is an extremely common dermatological disorder affecting both men and women. Oral finasteride (FNS), a synthetic 4-aza-3-oxosteroid compound with poor aqueous solubility, blocks the peripheral conversion of testosterone to dihydrotestosterone (DHT) in a significant reduction in DHT concentration, achieving satisfactory results in alopecia treatment. However, its oral intake generally causes severe side effects. Considering that there is currently no scientifically proven treatment, new drug delivery systems able to improve alopecia therapy are urgently required. Methods: In this study, polymeric nanoparticles have been proposed as a new carrier for topical delivery of FNS in hair follicles. Results and Conclusions: Polymeric nanoparticles, prepared by using a modified method of the emulsification/solvent diffusion, showed a mean particle size around 300 nm, which may be sufficient for reaching the dermis and hair follicles and negative zeta potential values. Scanning electron microscope measurements showed that all the polymeric nanoparticles exhibited a spherical shape and a smooth surface regardless of their composition. A high encapsulation efficiency was achieved for FNS (79.49 ± 0.47%). In vitro release assays in physiological conditions demonstrated that nanoparticles yielded a prolonged release of FNS for 3 h. Skin assays through an in vitro permeation study demonstrated that nanoparticles had low levels of penetration of FNS, improving its time residence onto the skin. All excipients used in nanoparticle composition and in 3 different vehicles were safe. These results suggest that the proposed novel formulation presents several good characteristics indicating its suitability for dermal delivery of FNS for alopecia treatment.

Bioproduction of gold nanoparticles for photothermal therapy

BACKGROUND Photothermal response of plasmonic nanomaterials can be utilized for a number of therapeutic applications such as the ablation of solid tumors. METHODS & RESULTS Gold nanoparticles were prepared using different methods. After optimization, we applied an aqueous plant extract as the reducing and capping agent of gold and maximized the near-infrared absorption (650-900 nm). Resultant nanoparticles showed good biocompatibility when tested in vitro in human keratinocytes and yeast Saccharomyces cerevisiae. Gold nanoparticles were easily activated by controlled temperature with an ultrasonic water bath and application of a pulsed laser. CONCLUSION These gold nanoparticles can be synthesized with reproducibility, modified with seemingly limitless chemical functional groups, with adequate controlled optical properties for laser phototherapy of tumors and targeted drug delivery.

Unsaponifiable matter from oil of green coffee beans: cosmetic properties and safety evaluation

Abstract Context: Unsaponifiable matter (UM), a fraction of green coffee oil (GCO) contains functional compounds responsible for desirable cosmetic properties such as UV-B absorption. Objectives: To evaluate oil content and sun protection factor (SPF) variability of the two most important species of coffee and, the toxic and cytotoxic effects, as well as cosmetic properties, including antioxidant and antimicrobial activities of UM obtained from green Coffea arabica seed oil. Materials and methods: The safety and potential cosmetic properties of UM extracted from green coffee oil (GCO) were evaluated by the brine shrimp viability and the MTT cytotoxicity assays. The SPF and antioxidant activity were evaluated using in vitro methods. Results: Relevant cytotoxicity was found against keratinocytes for concentrations ≥25 µg/mL and in the brine shrimp assay (LC50 24 µg/mL). Antimicrobial and antioxidant activities (IC50 1448 µg/mL) were low in UM but SPF was 10 times higher than in GCO. Conclusion: UM is a novel potential UV-B absorbent but its use as a cosmetic ingredient should be better considered due to the considerable cytotoxicity shown in the experimental conditions described.

Evaluation of a New Topical Treatment for Acne with Azelaic Acid-Loaded Nanoparticles

Azelaic acid, a saturated dicarboxylic acid, is used in the treatment of acne [1,2]. However, some side effects and low patient compliance have been associated with several topical formulations of azelaic acid [3,4]. Thus, nanotechnology presents an innovative strategy that can overcome these problems [5]. Polymeric nanoparticles are generally applied to control drug release and to reduce local drug toxicity. In this study, we used the polymer PLGA (acid poly (DL-lactic-co-glycolic)) which is a biocompatible and biodegradable polymer that provides a slow and controlled drug release [6]. The aim of this study was to evaluate a new topical treatment for acne with azelaic acid-loaded PLGA nanoparticles in terms of size, surface charge, encapsulation efficiency, morphology, drug-polymer interactions, efficacy, toxicity and safety of excipients.

Biological activity screening of seven Plectranthus species: Pesquisa de actividade biológica de sete espécies de Plectranthus

Natural products from Plectranthus spp. plants have an ethnopharmacological use, inspiring several scientific investigations. As such, this work aims to perform a biological activity screening in order to scientifically validate the use of these plants. Assays on in vitro acetylcholinesterase (AChE) inhibition, antioxidant effects, antimicrobial activity and Artemia salina lethality were performed on seven Plectranthus spp. extracts (P. swynnertonii, P. welwischii, P. woodii, P. cylindraceus, P. spicatus, P. ramosior and P. petiolaris). Acetonic extracts were obtained by sonication (10% w/v), where P. ramosior had the highest yield of dry extract (13.49% w/w). In the AChE inhibition assay, only P. cylindraceus extract decreased enzymatic activity (30.2 ± 3.78%). The antimicrobial activity was screened using the well diffusion method, against Gram positive and negative bacteria and yeast. P. ramosior extract showed not only an inhibition zone against S. aureus and C. albicans (15 and 11 mm, respectively), but also the highest scavenging activity (DPPH method, 36.4 ± 0.04%). On the lethality test in A. salina, P. swynnertonnii extract was the most toxic (LC50 = 0.036 mg/L). These preliminary results showed that P. cylindraceus, P. ramosior and P. swynnertonnii are potential bioactive extracts for further isolation and antimicrobial and cytotoxic studies.