Curcumin-loaded polymeric and lipid nanocapsules: preparation, characterization and chemical stability evaluation

Polymeric and lipid nanocapsules suspensions of the natural compound curcumin were prepared in order to overcome limitations associated with its clinical applications, such as poor aqueous solubility and susceptibility to hydrolytic and photochemical degradation. Nanocapsule suspensions were prepared by nanoprecipitation and phase inversion methods, respectively. The curcumin formulations were investigated for physicochemical characteristics and in vitro drug release. The hydrolytic and photochemical degradation of the drug associated with the nanocarriers was also determined. For all formulations, the entrapment efficiency values were higher than 99 %. The aqueous colloidal suspensions of curcumin resulted in an increase in drug concentration by a factor of up to 46.103 times. Moreover, stability studies indicated that nanoencapsulation slows down the hydrolytic and photochemical degradations of curcumin. The strategy of nanoencapsulation into polymeric and lipid nanocapsules produced a formulation of curcumin with high drug loading and improved stability, representing a good strategy for the delivery of this drug.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Curcumin-loaded polymeric and lipid nanocapsules: preparation, characterization and chemical stability evaluation

Polymeric and lipid nanocapsules suspensions of the natural compound curcumin were prepared in order to overcome limitations associated with its clinical applications, such as poor aqueous solubility and susceptibility to hydrolytic and photochemical degradation. Nanocapsule suspensions were prepared by nanoprecipitation and phase inversion methods, respectively. The curcumin formulations were investigated for physicochemical characteristics and in vitro drug release. The hydrolytic and photochemical degradation of the drug associated with the nanocarriers was also determined. For all formulations, the entrapment efficiency values were higher than 99 %. The aqueous colloidal suspensions of curcumin resulted in an increase in drug concentration by a factor of up to 46.103 times. Moreover, stability studies indicated that nanoencapsulation slows down the hydrolytic and photochemical degradations of curcumin. The strategy of nanoencapsulation into polymeric and lipid nanocapsules produced a formulation of curcumin with high drug loading and improved stability, representing a good strategy for the delivery of this drug.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Curcumin-loaded polymeric and lipid nanocapsules: preparation, characterization and chemical stability evaluation

Polymeric and lipid nanocapsules suspensions of the natural compound curcumin were prepared in order to overcome limitations associated with its clinical applications, such as poor aqueous solubility and susceptibility to hydrolytic and photochemical degradation. Nanocapsule suspensions were prepared by nanoprecipitation and phase inversion methods, respectively. The curcumin formulations were investigated for physicochemical characteristics and in vitro drug release. The hydrolytic and photochemical degradation of the drug associated with the nanocarriers was also determined. For all formulations, the entrapment efficiency values were higher than 99 %. The aqueous colloidal suspensions of curcumin resulted in an increase in drug concentration by a factor of up to 46.103 times. Moreover, stability studies indicated that nanoencapsulation slows down the hydrolytic and photochemical degradations of curcumin. The strategy of nanoencapsulation into polymeric and lipid nanocapsules produced a formulation of curcumin with high drug loading and improved stability, representing a good strategy for the delivery of this drug.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Development and validation of a fluorimetric method to determine curcumin in lipid and polymeric nanocapsule suspensions

A simple, rapid, and sensitive fluorimetric method was developed and validated to quantify curcumin in lipid and polymeric nanocapsule suspensions, using acetonitrile as a solvent. The excitation and emission wavelengths were set at 397 nm and 508 nm, respectively. The calibration graph was linear from 0.1 to 0.6 µg/mL with a correlation coefficient of 0.9982. The detection and quantitation limits were 0.03 and 0.10 µg/mL, respectively. The validation results confirmed that the developed method is specific, linear, accurate, and precise for its intended use. The current method was successfully applied to the evaluation of curcumin content in lipid and polymeric nanocapsule suspensions during the early stage of formulation development.Um método fluorimétrico simples, rápido e sensível foi desenvolvido e validado para quantificação da curcumina em suspensões de nanocápsulas lipídicas e poliméricas, usando acetonitrila como solvente. Os comprimentos de onda de excitação e emissão foram 397 nm e 508 nm, respectivamente. Nas condições testadas, a curva de calibração demonstrou-se linear na faixa de 0,1 a 0,6 µg/mL, exibindo coeficiente de correlação de 0,9982. Os limites de detecção e quantificação foram 0,03 e 0,10 µg/mL, respectivamente. Os resultados da validação confirmaram que o método desenvolvido é específico, linear, exato e preciso para o uso proposto. O presente método foi aplicado com sucesso para a avaliação do teor de curcumina nas suspensões de nanocápsulas lipídicas e poliméricas durante o estágio inicial do desenvolvimento da formulação

Polystyrene-b-poly (acrylic acid) nanovesicles coated by modified chitosans for encapsulation of minoxidil

In this work, polystyrene-b-poly (acrylic acid) (PS-b-PAA) nanovesicles were coated by modified chitosans aiming at studying its physicochemical parameters. The chitosan (CS) was chemically modified to add hydrophilic and/or hydrophobic groups, obtaining three modified chitosans. The PS-b-PAA nanovesicles were obtained by organic (1,4-dioxane) cosolvent method in water, resulting in nanovesicles with less than 150 nm of diameter (polydispersibility index - PDI at 90° = 0.106), measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM), and negative zeta potential (-37.5 ± 3.2 mV), allowing the coating of its surface with oppositely charged polysaccharides, such as the CS and the modified chitosans. The coating process was made by mixing the colloidal suspensions with the CS and the modified chitosans at specific ENT#091;CS-xENT#093;/ENT#091;PS-b-PAAENT#093; ratios (0.001 to 1.0 wt %) and measuring the change in size and surface charge by DLS and zeta potential. Upon reaching maximum adsorption, the zeta potential parameter was positively stabilized (+26.7 ± 4.1 mV) with a hydrodynamic diameter slightly longer (< 200 nm of diameter). The encapsulation efficiency (EE) of minoxidil, quantified by capillary electrophoresis, was 50.7%, confirming their potential as drug delivery carriers and the coating process showed the possibility of controlling the surface charge nature of these nanovesicles

Determination of structural and mechanical properties, diffractometry, and thermal analysis of chitosan and hydroxypropylmethylcellulose (HPMC) films plasticized with sorbitol

In this work, the structural, mechanical, diffractometric, and thermal parameters of chitosan-hydroxypropylmethylcellulose (HPMC) films plasticized with sorbitol were studied. Solutions of HPMC (2% w/v) in water and chitosan (2% w/v) in 2% acetic acid solution were prepared. The concentration of sorbitol used was 10% (w/w) to both polymers. This solutions were mixed at different proportions (100/0; 70/30; 50/50; 30/70, and 0/100) of chitosan and HPMC, respectively, and 20 mL was cast in Petri dishes for further analysis of dried films. The miscibility of polymers was assessed by X-ray diffraction, scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The results obtained indicate that the films are not fully miscible at a dry state despite the weak hydrogen bonding between the polymer functional groups

Autoassociação de misturas dos Surfactantes Dodecanoato de Sódio (SDoD) e Decanoato de Sódio (SDeC) com o Polímero Hidrofobicamente Modificado Etil(Hidroxietil)Celulose (EHEC)

In this work, the interactions between the non-ionic polymer of ethyl(hydroxyethyl)cellulose (EHEC) and mixed anionic surfactant sodium dodecanoate (SDoD)-sodium decanoate (SDeC) in aqueous media, at pH 9.2 (20 mM borate/NaOH buffer) were investigated by electric conductivity and light transmittance measurements at 25 ºC. The parameters of the surfactant to polymer association processes such as the critical aggregation concentration and saturation of the polymer by surfactants were determined from plots of specific conductivity vs total surfactant concentration, [surfactant]tot = [SDoD] + [SDeC]. Through the results was not observed a specific link of polymer with the surfactant, implying therefore a phenomenon only cooperative association