Dexamethasone Acetate Nanocrystals, Characterization and Dissolution Studies in Presence of Polymorphic Phases.

BACKGROUND: A drug with poor water-solubility, like Dexamethasone acetate, can present lower bioavailability conventional for pharmaceutical formulations, and the presence of polymorphs in the raw material can lead to drug quality problems. OBJECTIVE: In this study, nanocrystals of dexamethasone acetate were synthesized by high pressure homogenizer (HPH) method in surfactant poloxamer 188 (P188) solid dispersion and the bioavailable in raw material with polymorphism presence was evaluated. METHODS: The powder pre-suspension was prepared by the HPH process, and the nanoparticles formed were incorporated in P188 solutions. The nanocrystals formed were characterized by techniques of XRD, SEM, FTIR, thermal analysis by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), dynamic light scattering (DLS) to analyze the particle size and zeta potential, and in vitro evaluation by dissolution studies. RESULTS: The characterization techniques were adequate to show the presence of raw material with physical moisture between two dexamethasone acetate polymorphs. The nanocrystals formed in the presence of the P188 in the formulation showed a considerable increase in the rate of dissolution of the drug in the medium and in the size of the stable nanocrystals, even in the presence of dexamethasone acetate polymorphs. CONCLUSION: The results showed that it was possible to produce dexamethasone nanocrystals by HPH process with regular size by the presence of the small amount of P188 surfactant. This article presents a novelty in the development of dexamethasone nanoparticles that have different polymorphic forms in their physical composition.

ZnO@ZIF-8 Nanoparticles as Nanocarrier of Ciprofloxacin for Antimicrobial Activity.

Numerous antimicrobial drugs have been prescribed to kill or inhibit the growth of microbes such as bacteria, fungi, and viruses. Despite the known therapeutic efficacy of these drugs, inefficient delivery could result in an inadequate therapeutic index and several side effects. In order to overcome this adversity, the present study investigated antibiotic drug loading in zeolitic imidazolate frameworks (ZIFs), in association with ZnO nanoparticles with known antimicrobial properties. In an economic synthesis method, the ZnO surface was first converted to ZIF-8 with 2-methylimidazole as a ligand, resulting in a ZnO@ZIF-8 structure. This system enables the high drug-loading efficiency (46%) of an antimicrobial drug, ciprofloxacin, within the pores of the ZIF-8. This association provides a control of the release of the active moieties, in simulated body-fluid conditions, with a maximum of 67% released in 96 h. The antibacterial activities of ZnO@ZIF-8 and CIP-ZnO@ZIF-8 were tested against the Gram-positive Staphylococcus aureus strain and the Gram-negative Pseudomonas aeruginosa strain, showing good growth inhibition. This result was obtained by combining ZnO@ZIF-8 with ciprofloxacin in a minimal inhibitory concentration (MIC) that was 10 times lower than ZnO@ZIF-8 for S. aureus and 200 times lower for P. aeruginosa, suggesting that CIP-ZnO@ZIF-8 may have potential application in prolonged antimicrobial treatment.

Sustainable Antibacterial Activity of Polyamide Fabrics Containing ZnO Nanoparticles.

In this study, we present an unprecedented study on the influence of parameters such as dyeing, softening, and number of washes on the maintenance of the antibacterial activity of polyamide fabrics containing zinc oxide nanoparticles (ZnO NPs) impregnated by a simple and easy-to-scale technique. ZnO NPs were synthesized by the sol-gel method at different reaction times (1, 3, and 24 h), followed by surface modification with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) and water dispersion. The reaction times of ZnO NP synthesis were modified to evaluate their influence on particle size and antibacterial activity after impregnation in fabrics. The presence of ZnO NPs in fabrics was observed by different techniques such as X-ray diffraction, infrared vibrational spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The mean diameter values of the ZnO NPs calculated in this work from different techniques remained at 5 nm regardless of the reaction time revealing the efficient control of the nanoparticle size, important for desired applications as ZnO NPs smaller than 10 nm show improved antibacterial activity. The antibacterial activity of fabrics containing ZnO NPs indicated that polyamide fabrics after impregnation with ZnO NPs synthetized have great and similar biocidal potential against Staphylococcus aureus and Escherichia coli both with and without the presence of a fabric softener or a dye. The antibacterial behavior of the different polyamide fabrics remained after 10 and 20 washing cycles. The results shown in this study demonstrated the possibility of obtaining polyamide fabrics containing ZnO NPs with the antibacterial activity resistant to chemical treatments used by industries as a softener or a dye. The results also reveal the maintenance of the antimicrobial activity of fabrics after several washing cycles. The reaction time of 1 for the production of ZnO NPs and the versatility of polyamide fabrics allow their application in different environments to control microbial infections.

Physicochemical characterization of drug nanocarriers.

Pharmaceutical design has enabled important advances in the prevention, treatment, and diagnosis of diseases. The use of nanotechnology to optimize the delivery of drugs and diagnostic molecules is increasingly receiving attention due to the enhanced efficiency provided by these systems. Understanding the structures of nanocarriers is crucial in elucidating their physical and chemical properties, which greatly influence their behavior in the body at both the molecular and systemic levels. This review was conducted to describe the principles and characteristics of techniques commonly used to elucidate the structures of nanocarriers, with consideration of their size, morphology, surface charge, porosity, crystalline arrangement, and phase. These techniques include X-ray diffraction, small-angle X-ray scattering, dynamic light scattering, zeta potential, polarized light microscopy, transmission electron microscopy, scanning electron microcopy, and porosimetry. Moreover, we describe some of the commonly used nanocarriers (liquid crystals, metal-organic frameworks, silica nanospheres, liposomes, solid lipid nanoparticles, and micelles) and the main aspects of their structures.

A influência do complexo B e do laser de baixa intensidade no processo de cicatrização de feridas odontológicas / The influence of B complex and low intensity laser in the healing process of dental wounds

Esforços têm sido concentrados na busca de um fármaco que tenha eficácia clínica no processo de cicatrização de feridas odontológicas. O complexo B pode ser importante no processo de cicatrização e reparação porque é constituído por nutrientes necessários às funções fisiológicas normais ou às reações metabólicas específicas. Além disso, a terapia com laser de baixa intensidade modula vários processos biológicos em modelos animais e em humanos, estimulando a síntese de colágeno, promovendo o processo de regeneração do músculo esquelético após injúria, diminuindo a resposta inflamatória, elevando a neoformação de vasos sanguíneos e auxiliando no processo de cicatrização. Desta maneira, é relevante o estudo da influência do complexo B e do laser de baixa intensidade na tentativa de melhorar o processo de cicatrização de feridas odontológicas, aumentando a eficácia clínica. Essa revisão bibliográfica sugere que tanto o laser de baixa intensidade como o complexo B podem aumentar o processo de cicatrização em feridas e procedimentos odontológicos.

Currently, efforts have been concentrated in the search for a drug clinically efficient on healing dental wounds. The B complex may be important in wound healing process since it is composed of nutrients necessary for normal physiological functions or for specific metabolic reactions. The low intensity laser therapy modulates various biological processes in both animals and humans stimulating collagen synthesis, promoting the regeneration process of skeletal muscle injury after injury In addition it reduces the inflammatory response, increasing the formation of new blood vessels and aiding the healing process. Therefore it is important to study the influence of B complex and of low intensity laser aiming to improve the healing process of dental wounds, increasing clinical efficacy. This literature review suggests that both B complex and low intensity laser therapy can improve the healing process of dental wounds and dental procedures.