Bio-Inspired Carbon Dots as Malondialdehyde Indicator for Real-Time Visualization of Lipid Peroxidation in Depression.

Brain lipidic peroxidation is closely associated with the pathophysiology of various psychiatric diseases including depression. Malondialdehyde (MDA), a reactive aldehyde produced in lipid region, serves as a crucial biomarker for lipid peroxidation. However, techniques enabling real-time detection of MDA are still lacking due to the inherent trade-off between recognition dynamics and robustness. Inspired by the structure of phospholipid bilayers, amphiphilic carbon dots named as CG-CDs targeted to cell membrane are designed for real-time monitoring of MDA fluctuations. The design principle relies on the synergy of dynamic hydrogen bonding recognition and cell membrane targetability. The latter facilitates the insertion of CG-CDs into lipid regions and provides a hydrophobic environment to stabilize the labile hydrogen bonding between CG-CDs and MDA. As a result, recognition robustness and dynamics are simultaneously achieved for CG-CDs/MDA, allowing for in situ visualization of MDA kinetics in cell membrane due to the instant response (<5 s), high sensitivity (9-fold fluorescence enhancement), intrinsic reversibility (fluorescence on/off), and superior selectivity. Subsequently, CG-CDs are explored to visualize nerve cell membrane impairment in depression models of living cells and zebrafish, unveiling the extensive heterogeneity of the lipid peroxidation process and indicating a positive correlation between MDA levels and depression.

Core-shell structured carbon dots with up-conversion fluorescence and photo-triggered nitric oxide-releasing properties.

Cancer-targeted nanotechnology has a new trend in the design and preparation of new materials with functions for imaging and therapeutic applications simultaneously. As a new type of carbon nanomaterial, the inherent core-shell structured carbon dots (CDs) can be designed to provide a modular nanoplatform for integration of bioimaging and therapeutic capabilities. Here, core-shell structured CDs are designed and synthesized from levofloxacin and arginine and named Arg-CDs, in which levofloxacin-derived chromophores with up-conversion fluorescence are densely packed into the carbon core while guanidine groups are located on the shell, providing nitric oxide (NO) for photodynamic therapy of tumors. Moreover, the chromophores in the carbon core irradiated by visible LED light generate large amounts of reactive oxygen species (ROSs) that will oxidize the guanidine groups located on the shell of the Arg-CDs and further increase the NO releasing capacity remarkably. The as-synthesized Arg-CDs show excellent biocompatibility, bright up-conversion fluorescence, and a light-controlled ROS & NO releasing ability, which can be a potential light-modulated nanoplatform to integrate bioimaging and therapeutic functionalities.

Efficiency of the photodynamic therapy on viability of Streptococcus mutans in the oral cavity using chitosan nanoparticles: an in vitro study.

PURPOSE: This study aimed to investigate the efficiency of antimicrobial photodynamic therapy (aPDT) on Streptococcus mutans biofilm in the oral cavity using the photosensitizer chloroaluminum phthalocyanine encapsulated in chitosan nanoparticles (ClAlPc/Ch) at three preirradiation times. METHODS: Biofilms of Streptococcus mutans strains (ATCC 25,175) were cultivated on bovine tooth blocks and exposed to a 10% sucrose solution three times a day for 1 min over three consecutive days. The samples were randomly distributed into five treatment groups (n = 5): (I) aPDT with ClAlPc/Ch with a preirradiation time of 5 min (F5), (II) aPDT with ClAlPc/Ch with a preirradiation time of 15 min (F15), (III) aPDT with ClAlPc/Ch with a preirradiation time of 30 min (F30), (IV) 0.12% chlorhexidine digluconate (CHX), and (V) 0.9% saline solution (NaCl). After treatment, the S. mutans biofilms formed on each specimen were collected to determine the number of viable bacteria (colony-forming units (CFU)/mL). Data were analyzed for normality using the Shapiro-Wilk test and the analysis of variance (ANOVA) and Tukey HSD tests to analyze the number of viable bacteria (α = 0.05). RESULTS: The one-way ANOVA showed a difference between the groups (p = 0.0003), and the Tukey HSD posttest showed that CHX had the highest microbial reduction of S. mutans, not statistically different from the F5 and F15 groups, whereas the NaCl group had the lowest microbial reduction statistically similar to the F30 group. CONCLUSION: The results demonstrate that aPDT mediated by ClAlPc/Ch when used at preirradiation times of 5-15 min can be an effective approach in controlling cariogenic biofilm of S. mutans, being an alternative to 0.12% CHX.

Renal proximal tubule-on-a-chip in PDMS: fabrication, functionalization, and RPTEC:HUVEC co-culture evaluation.

'On-a-chip' technology advances the development of physiologically relevant organ-mimicking architecture by integrating human cells into three-dimensional microfluidic devices. This method also establishes discrete functional units, faciliting focused research on specific organ components. In this study, we detail the development and assessment of a convoluted renal proximal tubule-on-a-chip (PT-on-a-chip). This platform involves co-culturing Renal Proximal Tubule Epithelial Cells (RPTEC) and Human Umbilical Vein Endothelial Cells (HUVEC) within a polydimethylsiloxane microfluidic device, crafted through a combination of 3D printing and molding techniques. Our PT-on-a-chip significantly reduced high glucose level, exhibited albumin uptake, and simulated tubulopathy induced by amphotericin B. Remarkably, the RPTEC:HUVEC co-culture exhibited efficient cell adhesion within 30 min on microchannels functionalized with plasma, 3-aminopropyltriethoxysilane, and type-I collagen. This approach significantly reduced the required incubation time for medium perfusion. In comparison, alternative methods such as plasma and plasma plus polyvinyl alcohol were only effective in promoting cell attachment to flat surfaces. The PT-on-a-chip holds great promise as a valuable tool for assessing the nephrotoxic potential of new drug candidates, enhancing our understanding of drug interactions with co-cultured renal cells, and reducing the need for animal experimentation, promoting the safe and ethical development of new pharmaceuticals.

Chitosan nanoparticles loaded with epigallocatechin-3-gallate: synthesis, characterisation, and effects against Streptococcus mutans biofilmEpigallocatechin-loaded chitosan nanoparticles: effects against Streptococcus mutans biofilm.

This study evaluated the effects of chitosan nanoparticles loaded with epigallocatechin-3-gallate (EGCG) against Streptococcus mutans biofilm. EGCG-loaded chitosan (Nchi + EGCG) nanoparticles and Chitosan (Nchi) nanoparticles were prepared by ion gelation process and characterised regarding particle size, polydispersion index, zeta potential, and accelerated stability. S mutans biofilms were treated twice daily with NaCl 0.9% (negative control), Nchi, Nchi + EGCG, and chlorhexidine (CHX) 0.12% (positive control). After 67 h, the biofilms were evaluated for acidogenesis, bacterial viability and dry weight. Biofilm morphology and structure were analysed by scanning electron microscopy. The nanoformulations presented medium to short-term stability, size of 500 nm, and polydispersion index around 0.400. Treatments affected cell morphology and biofilm structure. However, no effects on microbial viability, biofilm dry weight, and acidogenesis were observed. Thus, the nanoformulations disassembled the biofilm matrix without affecting microbial viability, which makes them promising candidates for the development of dental caries preventive and therapeutic agents.

Development of Liposomes Loaded with Chloroaluminum Phthalocyanine for Application of Photodynamic Therapy in Breast Cancer.

Chloraluminium phthalocyanine (ClAlPc) has potential therapeutic effect for the treatment of cancer; however, the molecule is lipophilic and may present self-aggregation which limits its clinical success. Thus, nanocarriers like liposomes can improve ClAlPc solubility, reduce off-site toxicity and increase circulation time. For this purpose, developing suitable liposomes requires the evaluation of different lipid compositions. Herein, we aimed to develop liposomes containing soy phosphatidylcholine (SPC), 1,2-distearoyl-sn-glycero- 3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPEPEG2000), cholesterol and oleic acid loaded with ClAlPc using the surface response methodology and the Box-Behnken design. Liposomes with particle size from 110.93 to 374.97 nm and PdI from 0.265 to 0.468 were obtained. The optimized formulation resulted in 69.09 % of ClAlPc encapsulated, with particle size and polydispersity index, respectively, at 153.20 nm and 0.309, providing stability and aggregation control. Atomic force microscopy revealed vesicles in a spherical or almost spherical shape, while the analyzes by Differential Scanning Calorimetry (DSC), Powder X-ray Diffraction (PXRD), and Fourier transform infrared spectroscopy (FTIR) suggested that the drug was adequately incorporated into the lipid bilayer of liposomes, in its amorphous state or molecularly dispersed. In vitro studies conducted in breast cancer cells (4T1) showed that liposome improved phototoxicity compared to the ClAlPc solution. ClAlPc-loaded liposomes also enhanced the production of ROS 3-fold compared to the ClAlPc solution. Finally, confocal microscopy and flow cytometry demonstrated the ability of the liposomes to enter cells and deliver the fluorescent ClAlPc photosensitizer with dose and time-dependent effects. Thus, this work showed that Box-Behnken factorial design was an effective strategy for optimizing formulation development. The obtained ClAlPc liposomes can be applied for photodynamic therapy in breast cancer cells.

Longitudinal analyses of composite resin restoration on erosive lesions: effect of dentin treatment with a chitosan nanoformulation containing green tea

Aim To evaluate the influence of the biomodification of erosive lesions with a chitosan nanoformulation containing green tea (NanoCsQ) on the clinical performance of a composite resin. Methods The study was performed in a split-mouth, randomized and double-blinded model with 20 patients with 40 erosive lesions. The patient's teeth were randomized into two groups (n=20) according to the surface treatment: 1) Without biomodification (control), and 2) Biomodification with NanoCsQ solution (experimental). The lesions were restored with adhesive (Tetric N-bond, Ivoclar) and composite resin (IPS Empress Direct, Ivoclar). The restorations were polished and 7 days (baseline), 6 months, and 12 months later were evaluated according to the United States Public Health Service (USPHS) modified criteria, using clinical exam and photographics. Data were analyzed by Friedman's and Wilcoxon signed-rank tests. Results No significant differences were found between the control and experimental groups (p=0.423), and also among the follow-up periods (baseline, six months, and 12 months) (p=0.50). Regarding the retention criteria, 90% of the restoration had an alpha score in the control group. Only 10% of the restorations without biomodification (control) had a score charlie at the 12-month follow-up. None of the patients reported post-operatory sensitivity. Conclusion The NanoCsQ solution did not negatively affect the performance of the composite resin restorations after 12 months.

Experimental study of the neurotoxic effects of photodynamic therapy on the spinal cord / Estudo experimental dos efeitos neurotóxicos da terapia fotodinâmica na medula espinhal / Estudio experimental de los efectos neurotóxicos de la terapia fotodinámica en la médula espinal

ABSTRACT Objective To evaluate the effects of photodynamic therapy (PDT) on the dura mater using the photosensitizers aluminum chloride phthalocyanine and methylene blue in in vivo assays. Methods Fifty-six male Wistar rats were divided into two groups; one submitted to PDT and the other submitted to the photosensitizers without their photoactivation (control). The photosensitizers were applied to the dura mater after laminectomy at the T10 level. The methods used for assessment were the Basso, Beattie and Bresnahan (BBB) functional evaluation scale and study of the dura mater by light microscopy. Results No changes in motor activity were observed in the animals submitted to PDT compared to control. Histological and pathological evaluation did not show any differences between the group exposed to activated photosensitizers and the control group with regard to the inflammatory process and tissue necrosis. Conclusion The joint use of PDT with the photosensitizing pharmaceuticals aluminum chloride phthalocyanine and methylene blue did not induce any clinical neurotoxic effects or histological changes in the dura mater of the animals studied. Level de evidence V; Expert Opnion.

RESUMO Objetivo Avaliar os efeitos da terapia fotodinâmica (PDT) na dura-máter usando os fotossensibilizadores cloreto de alumínio ftalocianina e azul de metileno em ensaios in vivo. Métodos Cinquenta e seis ratos Wistar machos divididos em dois grupos; um submetido à PDT e o outro submetido aos fotossensibilizadores sem a fotoativação (controle). Os fotossensibilizadores foram aplicados sobre a dura-máter depois de laminectomia no nível T10. Os métodos de avaliação usados foram a escala de avaliação funcional de Basso, Beattie e Bresnahan (BBB) e o estudo da dura-máter por microscopia óptica. Resultados Não foram observadas alterações da atividade motora dos animais submetidos à PDT com relação ao grupo controle. A avaliação histológica e histopatológica não mostrou diferenças entre o grupo exposto aos fotossensibilizadores ativados e o grupo controle, com relação ao processo inflamatório e à necrose tecidual. Conclusões O uso conjunto de PDT e os fármacos fotossensibilizantes cloreto de alumínio ftalocianina e azul de metileno não induziu efeitos neurotóxicos clínicos e/ou alterações histológicas sobre a dura-máter dos animais estudados. Nível de evidência V; Opinião de Especialista.

RESUMEN Objetivo Evaluar los efectos de la terapia fotodinámica (PDT) en la duramadre utilizando los fotosensibilizadores de ftalocianina de aluminio clorada y azul de metileno en ensayos in vivo. Métodos Cincuenta y seis ratas Wistar machos se dividieron en 2 grupos; uno fue sometido a PDT y el otro sometido a fotosensibilizadores sin fotoactivación (control). Los fotosensibilizadores se aplicaron a la duramadre después de la laminectomía en el nivel T10. Los métodos de evaluación utilizados fueron la escala de evaluación funcional de Basso, Beattie y Bresnahan (BBB) y el estudio de la duramadre mediante microscopía óptica. Resultados No hubo cambios en la actividad motora de los animales sometidos a PDT en relación con el grupo de control. La evaluación histológica e histopatológica no mostró diferencias entre el grupo expuesto a fotosensibilizadores activados y el grupo de control con respecto al proceso inflamatorio y la necrosis tisular. Conclusiones El uso conjunto de PDT con las sustancias fotosensibilizadores ftalocianina de aluminio clorada y azul de metileno no indujo efectos neurotóxicos clínicos o cambios histológicos en la duramadre de los animales estudiados. Nivel de evidencia V; Opinión del Especialista.

Fluorometric quantification of protoporphyrin IX in biological skin samples from in vitro penetration/permeation studies

A fluorometric analytical method was developed for quantification of protoporphyrin IX (PpIX) in skin samples and receptor phase solution after in vitro cutaneous penetration/permeation studies. Analytical conditions used were: excitation and emission wavelengths: 400 nm and 632 nm; bandwidth: 0.5 nm; excitation and emission slits: 10/10. PpIX was recovered from two different layers of skin, the stratum corneum (SC) and the epidermis plus dermis ([E+D]), by vortex homogenization, probe and bath sonication, using DMSO as an extraction solvent. The detection and quantification limits were 0.002 and 0.005 μg/mL, respectively. The assay was linear from 0.005 - 0.5 μg/mL. The within-day and between-day assay precision and accuracy in DMSO and receptor phase solution were each studied at the two concentration levels 0.04 and 0.2 μg/mL, and 0.01 and 0.08 μg/mL, respectively. The coefficients of variation and deviation from the theoretical values were lower than 5%. The skin recovery of PpIX from SC and [E+D] layers using two different concentrations (0.5 and 1.0 μg/mL) were all above 90.0%. The method described has potential application to in vitro penetration/permeation studies of PpIX using porcine skin as a biological membrane model.

Um método analítico por espectrofluorimetria foi desenvolvido para quantificar a protoporfirina IX (Pp IX) em amostras de pele e fase receptora após a realização de testes in vitro de penetração/permeação cutâneas. As condições analíticas utilizadas foram: comprimentos de onda de excitação e emissão: 400 nm e 632 nm; largura de banda: 0,5 nm; fendas de excitação e emissão: 10/10. A PpIX foi extraída de amostras de estrato córneo (EC) e da epiderme sem estrato córneo + derme ([E+D]) através da agitação em vórtex e sonicação por haste e banho, utilizando-se o DMSO como solvente extrator. O limite de detecção e quantificação foram, respectivamente, de 0,002 e 0,005 μg/mL. O método mostrou-se linear da faixa de 0,005 - 0,5 μg/mL. A precisão e exatidão intra e inter-ensaio em DMSO e na fase receptora foram validadas utilizando-se duas concentrações distintas, respectivamente, de 0,004 e 0,2 μg/mL, e 0,01 e 0,08 μg/mL. Os valores de coeficiente de variação e o desvio do valor teórico foram inferiores a 5%. A recuperação da PpIX das camadas da pele (EC e [E+D]) utilizando-se duas concentrações distintas (0,5 e 1,0 μg/mL) foram todas acima de 90,0%. O método descrito pode ser utilizado para determinação da PpIX após estudos de penetração/permeação cutânea in vitro utilizando pele de porco como modelo de membrana.

Enhancing effect of modified beta-cyclodextrins on in vitro skin permeation of estradiol

Estradiol, the most important hormone in females, was complexed with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and randomly methylated beta-cyclodextrin (RM-b-CD). After obtaining the inclusion complexes, they were characterized by DSC, ¹H-NMR and solubility studies. The enhancing effect of CDs on estradiol skin permeation/retention was investigated in vitro using Franz diffusion cells. Both CDs increased estradiol aqueous solubility, but in different proportions. DSC and NMR-H¹ analyses showed that estradiol was complexed with both CDs and RM-beta-CD has stronger interactions with the hormone than HP-beta-CD. Moreover, complexes formation increased estradiol flux through the skin (P<0.01), but the hormone retention in the stratum corneum (SC) only increased after complexation with HP-beta-CD. On the other hand, only RM-b-CD was able to modify estradiol retention in the SC after skin pretreatment with CDs. The results suggest that the enhancing effect of CDs on estradiol flux through the skin may be mainly described as an increase in drug availability on the skin surface due to inclusion complexation. Furthermore, the formation of a significant reservoir of estradiol in the SC due to HP-beta-CD complexation makes it an interesting approach for estradiol transdermal delivery.

Estradiol, o mais importante hormônio feminino, foi complexado com hidroxipropil-beta-ciclodextrina (HP-beta-CD) e metil-beta-ciclodextrina randômica (RM-beta-CD). Após a obtenção dos complexos, os mesmos foram caracterizados por estudos de solubilidade, CDV e RMN-H¹. O efeito das CDs sobre a absorção/retenção do estradiol na pele foi investigado in vitro em células de difusão de Franz. As CDs aumentaram a solubilidade aquosa do estradiol em diferentes proporções. As análises de CVD e RMN-H¹ comprovaram a complexação do estradiol com ambas CDs, sendo que RM-beta-CD apresentou interação mais forte com estradiol do que HP-beta-CD. Mais adiante, a formação de complexos aumentou o fluxo de estradiol através da pele (P<0,01), mas o aumento de fármaco no estrato córneo (EC) foi observado somente após complexação com HP-beta-CD. Por outro lado, somente a RM-beta-CD foi capaz de aumentar a retenção do fármaco no EC após o pré-tratamento da pele com CDs. Os resultados sugerem que o efeito promotor das CDs no fluxo de estradiol pode ser descrito principalmente como aumento da disponibilidade de fármaco na superfície da pele devido à complexação. Além disso, a formação de um significativo reservatório do hormônio no EC torna a complexação com HP-beta-CD uma estratégia interessante para liberação transdérmica do estradiol.

Terapia fotodinâmica com ftalocianina de zinco tópica: avaliação da intensidade de fluorescência, absorção cutânea, alterações histológicas e imuno-histoquímicas na pele do modelo animal / Topical photodynamic therapy with zinc phthalocyanine: evaluation of fluorescence intensity, skin absorption, skin histological and immunohistochemical changes in animal model

FUNDAMENTOS - Ftalocianinas são promissores agentes fotossensibilizadores na terapia fotodinâmica (TFD). OBJETIVOS - Avaliar intervalos, veículos e a incorporação de promotor de absorção na formulação tópica da ftalocianina de zinco (FC-Zn). Avaliar alterações macro e micromorfológicas e a expressão de Fas promovidas pela TFD com FC-Zn tópica no modelo murino. MÉTODOS - Por meio da espectrometria de fluorescência, foram avaliadas combinações de diferentes períodos de oclusão tópica das formulações gel ou emulsão de FC-Zn (1mg/dl), com ou sem monoleína 5 por cento, no dorso do camundongo hairless. Após oito horas das diferentes formulações, os camundongos foram expostos ao laser de diodo de 670nm, dose de 50J/cm-². RESULTADOS - A fluorescência foi discretamente superior após oito horas e com a emulsão nos intervalos de uma, duas e quatro horas de oclusão. A intensidade do edema e da erosão correspondeu à necrose da epiderme e à imunoexpressão de Fas nos cortes histológicos de pele. CONCLUSÕES - Os achados indicam a ação fotodinâmica promovida pela interação entre FC-Zn e fonte de luz de 670nm. As alterações macro e micromorfológicas foram correspondentes e mais substanciais com a emulsão FC-Zn e monoleína, sugerindo a acentuação dos efeitos com essa formulação. A imunoexpressão de Fas e as alterações histológicas sugeriram a apoptose como mecanismo de morte celular na TFD com FC-Zn tópica.

BACKGROUND - Phthalocyanines are promising photosensitizers used in photodynamic therapy (PDT). OBJECTIVES - To evaluate the following parameters: intervals, vehicles and enhancer using topical zinc-phthalocyanine (Zn-PC) formulation. To examine macro and micromorphological changes and Fas expression induced by topical Zn-PC-PDT on murine skin. MATERIAL AND METHODS - Using fluorescence spectrometry, different intervals of topical occlusion employing Zn-PC gel or emulsion, with or without monolein 5 percent were studied. After an 8-hour occlusion of different formulations, the mice were exposed to 670 nm laser, at a 50 J.cm-² dose. RESULTS - Fluorescence was slightly higher after 8 hours, and also with emulsion formulation at one-, two- and four-hour occlusion periods. The intensity of edema and erosion were correlated to epidermal necrosis and to Fas immunoexpression in skin histological specimens. CONCLUSIONS - The results show the effects of photodynamic action promoted by the interaction between Zn-PC formulation and a 670-nm light source. Macro and micromorphological alterations were correlated and more substantial with monolein and Zn-PC emulsion, suggesting more marked effects with this formulation. The Fas immunoexpression and histological changes suggested that apoptosis plays a role in the mechanism of cell death caused by PDT based in Zn-PC.

Avaliação de células neoplásicas após terapia fotodinâmica / Evaluation of neoplasic cells after photodynamic therapy

Terapia fotodinâmica (TFD) vem sendo considerada um moderno tratamento para o câncer e severas outras condições médicas.O presente estudo tem por objetivo analisar as alterações morfológicas e ultraestruturais de células neoplásicas Hep-2 submetidas a TFD utilizando a Zinco Ftalocianina.Células Hep-2 foram cultivadas de maneira padrão com meio MEM, incubadas com a ZnPc na concentração 9mM por 1 hora, irradiadas com um laser de diodo, analisadas através de técnicas de Microscopia de Fluorescência utilizando marcadores específicos (DAPI e JC-1) e Microscopia Eletrônica de Transmissão. As células neoplásicas Hep-2 submetidas a TFD mostraram-se fotodanificadas morfológica e ultraestruturalmente, sendo possível observar algumas alterações nas organelas celulares. Portanto, pode-se concluir que após TFD utilizando a ZnPc estas células sofreram morte por apoptose...

Photodynamic Therapy (PDT) have been considered a modern treatment for cancer and several others medicalconditions. The present study has for objective to analyze the morphological and ultrastructural alterations of Hep-2 neoplasic cells submitting to PDT using a Zinc Phthalocyanine. Hep-2 cells were cultivated of standard form with MEM medium, incubated with the ZnPc at9mM concentration for 1 hour, irradiated with a diode laser, analyzed through of technique of Fluorescence Microcopy using specific staining (DAPI and JC-1) and Transmission Electronic Microscopy. The Hep-2 neoplasic cells submitted to PDT presented photodamaged morphological and ultrastructurally, have been possible to observe some alterations in the cell rganelles.Therefore, we can conclude that after PDT using the ZnPc these cells suffer death for apoptosis...

Enhancing effect of modified beta-cyclodextrins on in vitro skin permeation of estradiol

Estradiol, the most important hormone in females, was complexed with hydroxypropyl-b-cyclodextrin (HP-b-CD) and randomly methylated b-cyclodextrin (RM-b-CD). After obtaining the inclusion complexes, they were characterized by DSC, 1H-NMR and solubility studies. The enhancing effect of CDs on estradiol skin permeation/retention was investigated in vitro using Franz diffusion cells. Both CDs increased estradiol aqueous solubility, but in different proportions. DSC and NMR-H1 analyses showed that estradiol was complexed with both CDs and RM-b-CD has stronger interactions with the hormone than HP-b-CD. Moreover, complexes formation increased estradiol flux through the skin (P<0.01), but the hormone retention in the stratum corneum (SC) only increased after complexation with HP-b-CD. On the other hand, only RM-b-CD was able to modify estradiol retention in the SC after skin pretreatment with CDs. The results suggest that the enhancing effect of CDs on estradiol flux through the skin may be mainly described as an increase in drug availability on the skin surface due to inclusion complexation. Furthermore, the formation of a significant reservoir of estradiol in the SC due to HP-b-CD complexation makes it an interesting approach for estradiol transdermal delivery(AU)

Potential incorporation of 5-aminolevulinic acid in micelles and stratum corneum lipids liposomes: fluorescence quenching studies

The quenchings of pyrene fluorescence by 5-aminolevulinic acid (5-ALA) in dodecyl sulfate (SDS) micelles and stratum corneum lipids liposomes (SCLLs) were studied in order to verify the capacity of incorporation of 5-ALA in these systems. Static and dynamic quenching constants based on the simultaneous determination of fluorescence intensity quenching and fluorescence decay measurements were determined. 5-ALA was incorporated at crescent concentrations in SDS micelles and SCLLs containing the fluorescent probe (pyrene, 1,15 x '10 POT.menos 5 M') and the rate constants of quenching (kq) of pyrene were determined. 5-ALA was able to quench the fluorescence of the probe in both systems studied. A greater extent...