Photodynamic therapy (PDT) is a therapeutic modality that has shown effectiveness in the inactivation of cancer cell lines and microorganisms. Treatment consists of activating the photosensitizer (PS) upon light irradiation of adequate wavelength. After reaching the excited state, the PS can handle the intersystem conversion through energy transfer to the molecular oxygen, generating reactive oxygen species. This especially applies to singlet oxygen (O), which is responsible for the selective destruction of the sick tissue. Photosensitizing compounds (chlorophylls and derivatives) existing in the spinach extract have applicability for PDT. This study aimed to develop and characterize the thermoresponsive bioadhesive system composed of Pluronic F127 20.0%- and Carbopol 934P 0.2% (w/w) (FC)-containing chlorophyll-based extract 0.5% (w/w) (FC-Chl). Mechanical and rheological properties, in vitro release, sol-gel transition temperature, and ex vivo permeability of the spinach extract PS components (through pig ear skin) were investigated. Furthermore, photodynamic activity of the system was accessed through uric acid and time-solved measurements. The sol-gel transition temperature obtained for the FC-Chl system was 28.8 ± 0.3 °C. Rheological and texture properties of the platform were suitable for use as a dermatological system, exhibiting easy application and good characteristics of retention in the place of administration. In vitro release studies showed the presence of two distinct mechanisms that reasonably obey the zero-order and first-order kinetics models. PS components presented skin permeability and reached a permeation depth of 830 μm (between the epidermis and dermis). The photodynamic evaluation of the FC-Chl system was effective in the degradation of uric acid. The quantum yield (ΦO) and life time (τO) of singlet oxygen showed similar values for the spinach extract and the isolated chlorophyll a species in ethanol. These results allowed for the classification of the FC-Chl platform as potentially useful for the delivery of the chlorophyll-based extract in the topic PDT, suggesting that it is worthy for in vivo evaluation.

The design results were useful for developing of curcumin dosage form with good physicochemical characteristics and mucoadhesive properties for the bladder administration.

Safranine-O (Sf) is a photosensitizer (PS) displaying a remarkable potential for photodynamic therapy (PDT). In this work, we have used the combination of Sf with F127 Pluronic and Carbopol (C934P) to obtain a stimuliresponsive hydrogel (SR-Sf). This thermoresponsive-photoactive nanostructured system was prepared by two different methods: direct addition (DA) and solid dispersion (SD). Both SR-Sf have had their physical and chemical properties evaluated for veterinary applications, especially considering their ability to be used as a commercial product, aiming at the prophylactic or therapeutic treatment of breast gland infections. In general, the rheological and mechanical properties, as well as the sol−gel transition temperature, indicated suitable properties for using them as a topical system in veterinary (and human) applications. The ex vivo release studies showed a satisfactory permeation profile of the SR-Sf hydrogel, reaching the full length of the overall skin toward the dermis within 30 min of application (989 μm). The in vitro studies showed photodynamic inactivation using Sf-F127 with a significant reduction in isolated colonies. The in vivo case report with dairy goat demonstrated that the SR-Sf hydrogel veterinary use platform emerged as an innovative approach for the treatment of local infections without generating antibiotic residues in the milk produced.

Small wetlands are strongly bound to surrounding terrestrial habitats, so understanding their suitability after conversion to human land uses is critically important to produce an ecologically centred planning for amphibian species. Here, we explored how responses of amphibian assemblage to habitat conversion were influenced by reproductive modes in freshwater coastal wetlands in southern Brazil. We also assessed whether species from different biomes are affected in different ways by land conversion. Using data from tadpole assemblages in a transition zone between Atlantic Forest and Pampa, we tested the hypothesis that aquatic modes would be more affected by habitat conversion than are foam-nest species. Overall, quantitative data were influenced by the percentage of crop area, whereas assemblage structure derived from presence–absence data was associated with biome type. Species with aquatic egg-laying were influenced by the percentage of crop area, and many species were more abundant in ponds surrounded by up to 15% crop area in a 1000-m radius. However, foam-nest species were not influenced by any variable investigated (crops, planted pastures, urban areas and biome). This study has highlighted that agricultural conversion poses environmental filters to amphibian communities, selecting species according to some traits (adult reproductive strategies and tadpole plasticity).

In recent decades, the development of the environmentally responsive systems for drug delivery has been well regarded, with enormous potential in different applications. <P><P> Methods: These environmentally sensitive, smart, intelligent formulations have the ability to alter their physical properties in response to small changes in physical or chemical conditions, such as temperature, glucose, pH, ultrasound, light, electric field and redox potential with a huge potential in drug delivery systems. The use of formulations containing smart materials enables to carry the drug to the target tissue, cells and release in a triggered way. Consequently, they have demonstrated several advantages like decreased dose frequency, ease of preparation and administration, prolonged release with reduced side effects, as well as, reduced costs when compared to conventional processes for industrial applications. In this sense, many patents have deposited, displaying different pharmaceutical devices using responsive systems. <P><P> Results: There are more than twenty-five patents deposited about thermoresponsive systems. Furthermore, a few number of patents within glucose responsive, ultrasound responsive and light responsive deposited. There also are about eight patents that are pH-responsive, four as electric-field responsive. Most of them cover more than one type of stimuli. <P><P> Conclusion: Therefore, in this review, since 1975 to 2016, we have categorized, reviewed and discussed the patents, applications, pharmaceutical dosage forms, the importance and perspectives of this environmentally responsive approach as potentially useful therapeutic modality.