NLC-Based Sunscreen Formulations with Optimized Proportion of Encapsulated and Free Filters Exhibit Enhanced UVA and UVB Photoprotection.

The topical use of sunscreens is recommended for avoiding the damaging effects of UV radiation. However, improvements are still needed in the existing products to enhance their photoprotection effectiveness and safety. This involves minimizing the use of chemical UV filters while providing enhanced and prolonged photoprotection. This work investigated novel sunscreen formulations and their UV protection effects by encapsulating Uvinul® A, Tinosorb® S, and Uvinul® T150 into nanostructured lipid carriers (NLCs) based on bacuri butter and raspberry seed oil. First, the impact of critical formulation and process parameters on NLCs' particle size was evaluated using a 22 Face Centered Central Composite Design. Then, formulations were evaluated in terms of critical quality factors, in vitro skin permeation, and in vitro and in vivo photoprotection activities. The developed NLCs-containing formulations exhibited appropriate size (122-135 nm), PdI (<0.3), encapsulation efficiency (>90%), and drug content (>80%), which were preserved for at least 90 days under different stability conditions. Moreover, these NLCs-based formulations had equivalent skin permeation to emulsion-based controls, and the addition of NLCs into sunscreen cream bases in the optimum proportion of 20% (w/w) resulted in enhanced UVA and UVB photoprotection levels, despite a 10% reduction in the total filters content. Altogether, these results describe the application of nanoencapsulated organic UV filters in innovative sunscreen formulations to achieve superior photoprotection and cosmeceutical properties.

A new case of trombiculiasis caused by Eutrombicula daemoni Bassini-Silva & Jacinavicius, 2018 (Trombidiformes Trombiculidae) in a dog from Brazil

Chiggers are ectoparasites and can cause severe dermatitis in their hosts, known as trombiculiasis. Besides that, these mites can be vectors of bacteria of the genus Orientia, in various regions of the world. The genera Eutrombicula Ewing, 1938 is currently represented by more than 80 species worldwide. Species of this genus are recorded parasitizing reptiles, birds, and mammals. One of this species, Eutrombicula daemoni Bassini-Silva & Jacinavicius, 2018 was recently described causing trombiculiasis in a dog. Our goal is to report a new case of a dog’s trombiculiasis, including a new locality record for E. daemoni in Brazil. In May 2021, a female Shih-Tzu dog with three years old and with access to the forest of the Santa Tereza municipality, southeastern Brazil, sought veterinary medical attention for intense itching and erythema in the facial region. Mites were collected directly from the face of the dog. These materials were slide-mounted and deposited in the Acarological Collection of the Butantan Institute (IBSP). The material extracted from the dog was examined and identified as E. daemoni. Part of the fixation site tissue of the dog was collected, showing the feeding tube produced by the enzymatic reaction of saliva by the mite, known as a stylostome. In this report, we emphasize the occurrence of trombiculiasis in domestic animals that have access to forest regions, places that unfed chigger larvae live. Additionally, this record represents a new locality record for E. daemoni to the Espírito Santo State, Brazil.

Development and In Vitro Evaluation of Lyotropic Liquid Crystals for the Controlled Release of Dexamethasone.

In this study, amphiphilic polymers were investigated as biomaterials that can control dexamethasone (DXM) release. Such materials present interfacial properties in the presence of water and an oily phase that can result in lyotropic liquid crystalline systems (LLCS). In addition, they can form colloidal nanostructures similar to those in living organisms, such as bilayers and hexagonal and cubic phases, which can be exploited to solubilize lipophilic drugs to sustain their release and enhance bioavailability. It was possible to obtain lamellar and hexagonal phases when combining polyoxyethylene (20) cetyl ether (CETETH-20) polymer with oleic acid (OA), N-methylpyrrolidone (P), isopropyl myristate (IM), and water. The phases were characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheological, textural, and bioadhesion analyses followed by an in vitro release assay. All samples showed elastic behavior in the rheology studies and hexagonal samples containing P and IM showed the highest adhesiveness. The drug release profile of all LLCS presented an average lag time of 3 h and was best fitted to the Korsmeyer-Peppas and Weibull models, with controlled release governed by a combination of diffusion and erosion mechanisms. These systems are potential carriers for DXM and can be explored in several routes of administration, providing potential advantages over conventional pharmaceutical forms.

Surfactant systems for nasal zidovudine delivery: structural, rheological and mucoadhesive properties.

OBJECTIVES: Zidovudine is the antiretroviral drug most frequently used for the treatment of AIDS. Although its effectiveness is recognized, it undergoes extensive first-pass metabolism and exhibits poor oral bioavailability. The nasal route is an option for enhanced therapeutic efficacy and to reduce the extent of the first-pass effect. There are some mechanisms that limit intranasal absorption, such as mucociliary clearance, which rapidly removes the formulation from the nasal cavity. To improve the nasal residence time of zidovudine on the nasal mucosa, we aimed to develop a mucoadhesive surfactant system for zidovudine nasal administration. METHODS: Systems composed of PPG-5-CETETH-20 as surfactant, oleic acid and water were characterized by polarized light microscopy, small-angle X-ray scattering and rheological measurements. Mucoadhesion was investigated by phase behaviour studies, rheological synergism and mucoadhesive strength determination. KEY FINDINGS: Results indicate that the original formulations were microemulsions that displayed phase transition to a lamellar phase when brought into contact with aqueous nasal simulated mucus. The phase transition was accompanied by an increase in system elasticity and, irrespective of phase behaviour, all the systems showed a good mucoadhesive force. Thus, a viscous and mucoadhesive liquid crystalline matrix could be formed when the formulations were in contact with simulated mucus, which may prolong the residence time of zidovudine in the nasal cavity. CONCLUSIONS: These findings indicate a potentially useful system for nasal administration of zidovudine.

Development and in vitro evaluation of surfactant systems for controlled release of zidovudine.

The development of a controlled-release dosage form of zidovudine (AZT) is of crucial importance, in view of the pharmacokinetics of its toxic activity. A suitable drug delivery system could increase AZT bioavailability, reducing its dose-dependent side effects. In this study, systems composed of polyoxypropylene (5) polyoxyethylene (20) cetyl alcohol as surfactant (S), oleic acid as oil phase (O), and water (W) were developed, as possible AZT control release systems. They were characterized by polarized light microscopy (PLM), SAXS, and rheological analysis, followed by in vitro release assay. PLM and SAXS results indicated that the mixtures of S/O/W in the proportions 55/35/10 and 55/25/20 formed microemulsion (ME) systems, while 55/20/25 formed lamellar phase. The incorporation of AZT in these systems was greater than in water or oil; moreover, AZT incorporation did not significantly change the phase behavior of the mixtures. MEs behave as Newtonian fluids in flow rheological analysis and the lamellar phase as a pseudoplastic fluid. The release profile indicated that AZT could be released in a controlled manner, since an exponential pattern governs AZT diffusion, as demonstrated by the Weibull mathematical model. These systems are potential carriers for AZT and could have advantages over conventional pharmaceutical forms.

Doença de Paget com manifestaçöes nos maxilares / Paget's disease with maxillary manifestations

Discutimos um caso incomum de doença de Paget do osso, de apresentação nos maxilares. Esta forma rara de manifestação de uma doença sistêmica levou à dificuldade inicial em estabelecer o diagnóstico, sendo a etiologia firmada apenas pela biópsia da lesão. Utilizamos bisfosfonatos com boa resposta. Ressaltamos no artigo a necessidade do acompanhamento multidisciplinar desses pacientes devido às complicações odontológicas da doença quando localizada nos maxilares.