Cyclodextrins and ternary complexes: technology to improve solubility of poorly soluble drugs

Ciclodextrinas (CDs) são oligossacarídeos cíclicos, compostos por unidades D-glicopiranosídicas ligadas entre si por meio de ligações glicosídicas e sua principal propriedade está na capacidade de alterar as características físico-químicas e biológicas de fármacos com baixa solubilidade por meio da formação de complexos de inclusão fármaco:CD. Para a formação dos complexos de inclusão a molécula hospedeira necessita ajustar-se total ou parcialmente no interior da cavidade da CD, onde este ajuste está diretamente ligado a propriedades físico-químicas da molécula hóspede e hospedeira, facilidade de alojamento da molécula hóspede no interior da cavidade da CD, estequiometria, dose terapêutica e toxicidade. No entanto, as formas farmacêuticas podem atingir um elevado volume, em função da quantidade de CD requerida, sendo necessário aumentar sua eficiência de solubilização para que seja possível utilizar menores quantidades das mesmas. Isso pode ser obtido com a inclusão de pequenas quantidades de polímeros hidrossolúveis ao sistema. Nessa revisão, são abordados aspectos relacionados à complexação de fármacos com ciclodextrinas empregando-se polímeros hidrossolúveis para otimização da quantidade de CD utilizada na formulação, com a finalidade de aumentar a solubilidade do fármaco e reduzir o volume das preparações.Cyclodextrins (CDs) are cyclic oligosaccharides composed of D-glucopyranoside units linked by glycosidic bonds. Their main property is the ability to modify the physicochemical and biological characteristics of low-soluble drugs through the formation of drug:CD inclusion complexes. Inclusion complexation requires that host molecules fit completely or partially within the CD cavity. This adjustment is directly related to the physicochemical properties of the guest and host molecules, easy accommodation of guest molecules within the CD cavity, stoichiometry, therapeutic dose, and toxicity. However, dosage forms may achieve a high volume, depending on the amount of CD required. Thus, it is necessary to increase solubilization efficiency in order to use smaller amounts of CD. This can be achieved by adding small amounts of water-soluble polymers to the system. This review addresses aspects related to drug complexation with CDs using water-soluble polymers to optimize the amount of CD used in the formulation in order to increase drug solubility and reduce dosage form volume

Vitamin E in Human Skin: Functionality and Topical Products

Vitamins are part of the antioxidant system of human skin, and are detectable in different layers, so the topical application can be an alternative to maintain the functionality of the system. The capacity of the antioxidant gradient of keratinocytes is associated with attenuation of the action of related free radicals in both esthetics and health. These problems arise from extrinsic aging and are related to the risk of cancer. Vitamin E has been proven to have antioxidant and moisturizing properties in the skin and can protect against the damage of UVB radiation, with emphasis on the reduction of acute erythema and photoaging. The choice for the use of topical vitamin E, compared to the oral is given by the safety as mild irritation and it has potential for multifunctional topical formulations. The purpose of the chapter is to review the topical use of formulations with vitamin E, addressing the development, safe use and evaluation of effectiveness

Rutina como fotoestabilizadora de protetores solares de amplo espectro / Rutin as photostabilizer for broad spectrum sunscreens

The combination of butyl methoxydibenzoylmethane (BMBM) and octyl methoxycinnamate (EHMC) is widely used in pharmaceutical formulations but may exhibit alteration in spectral absorption following exposure to UV radiation. The addition of natural substances in sunscreen formulations has been explored regarding photoprotective efficacy. The main objective of this research was to evaluate the potential of rutin as a photostabilizer substance of EHMC and BMBM. The samples were evaluated before and after exposure to UV radiation to in vitro photoprotection and molecular interactions by 1H NMR, DSC, TG and qualitative analysis of the suppression of singlet energy state. The addition of rutin in the formulations containing BMBM and EHMC promoted an increase in the preservation of in vitro SPF of 53.9% to 65.8 (0.1% rutin ) and 70.8 % (1.0% rutin ). The DSC and TG curves of rutin showed interaction between the flavonoid and filters. The trans/cis ratio for EHMC improved from 5.5 ± 0.1 to 12.6 ± 0.4 with rutin addition. The suppression of the singlet state indicated that one of the mechanisms involved in the photostabilization is suppression of singlet excited state. These results can contribute to the development of broad-spectrum sunscreens formulations with increased safety and efficacy

Contribution of Topical Antioxidants to Maintain Healthy Skin—A Review

The skin is constantly exposed to various environmental stresses, in particular to the damage caused by pollution and ultraviolet radiation (UV), and as a consequence, the horny extract can be negatively impacted by the harmful influence of some of its surface components. The mechanisms involved in the degradation processes promoted by UV radiation are driven by the direct absorption of radiation via cellular chromophores, the formation of excited states and the consequent chemical reactions, or even by the photosensitization mechanisms, in which UV light is absorbed by the sensitizers that are excited and their reactions promote the formation of reactive oxygen species (ROS). The mechanisms of polluting agents are not yet fully understood, however, they indicate that one of the main mechanisms involved is oxidative stress by lipid peroxidation, with the ability to promote damage to the composition of sebum, the quality of the stratum corneum and also, promote aging skin. Recent studies demonstrate the potential of antioxidant agents, with an emphasis on products of natural origin, which try to promote the maintenance of the physiological balance of the skin