Desenvolvimento de formulações farmacêuticas contendo raloxifeno empregando os métodos de deposição interfacial de polímero pré-formado ou secagem por atomização vibracional

Partículas nanométricas e submicrométricas são desenvolvidas para controlar a liberação do fármaco, aumentar o efeito antiproliferativo e evitar o metabolismo pré-sistêmico de fármacos. Neste trabalho foram preparadas nanocápsulas através da deposição interfacial de polímeros pré-formados com os polímeros catiônico e aniônico, contendo cloridrato de raloxifeno, que apresentaram adequadas características nanotecnológicas. Dependendo do perfil de liberação in vitro do fármaco pôde-se obter um efeito antiproliferativo diferenciado em células de carcinoma mamário. A secagem por atomização vibracional é uma técnica recentemente utilizada na produção de partículas submicrométricas esféricas a partir de soluções aquosas ou orgânicas. A aplicação desta secagem no desenvolvimento de partículas poliméricas submicrométricas pulverulentas foi estudada. Inicialmente foram produzidos pós contendo dexametasona para administração pulmonar, apresentando diâmetro aerodinâmico adequado para esta via de administração (< 5 μm). A poli(ε-caprolactona) foi fundamental para modular a liberação in vitro do fármaco a partir do pó. A formulação contendo a menor proporção polimérica possibilitou uma distribuição granulométrica simétrica e adequada desaglomeração. Na sequência, partículas submicrométricas sólidas contendo cloridrato de raloxifeno no estado amorfo foram produzidas através da atomização vibracional. A presença do polímero na estrutura destas partículas também levou a uma liberação do fármaco sustentada. As formulações foram avaliadas em relação à deposição nas diferentes porções do trato respiratório in vitro, demonstrando uma adequada deposição pulmonar e atingindo as porções mais inferiores do trato respiratório. Além disso, um implante subcutâneo e biodegradável contendo cloridrato de raloxifeno foi produzido a partir da compressão manual de um pó preparado por secagem por atomização vibracional. O polímero [poli(ε-caprolactona)] e o óleo (mistura de triglicerídeos dos ácidos cáprico/caprílico) presentes na formulação foram fundamentais para a liberação do fármaco in vitro por 24 dias. O pó para administração pela via pulmonar e o implante subcutâneo contendo cloridrato de raloxifeno possibilitam a escolha de outras vias de administração para este fármaco, que apresenta um grande metabolismo de primeira passagem após administração oral. Para avaliar a biodisponibilidade do cloridrato de raloxifeno, foi validado um método analítico por cromatografia líquida de alta eficiência, com baixo limite de quantificação, para a análise deste fármaco no plasma de ratos. Este método está sendo aplicado em estudos farmacocinéticos após administração pulmonar e subcutânea das formulações desenvolvidos nesta tese. Assim, a nanoencapsulação do cloridrato de raloxifeno possibilitou um aumento no efeito antiproliferativo sobre as células de carcinoma mamário e formulações inovadoras foram produzidas a partir da secagem por atomização vibracional.Nano and submicron particles are produced to drug control release, improve the antiproliferative effect and prevent the presystemic metabolism of drugs. In this work cationic and anionic polymeric nanocapsules were prepared by interfacial deposition of preformed polymers containing raloxifene hydrochloride, showing adequate nanotechnological properties. Prolonged antiproliferative effect on breast carcinoma cells was depending on the in vitro drug release profile from the different formulations. The vibrational atomization spray-drying is a technique recently used for the production of submicrometer spherical particles from aqueous or organic solutions. The use of this drying in the development of polymeric submicrometer powders was studied. Dry powders containing dexamethasone were developed for the pulmonary administration, showing mass median aerodynamic diameter suitable for this route of administration (< 5 μm). Poly(ε-caprolactone) was essential to modulate the in vitro drug release from powder. The lowest drug:polymer ratio led to the symmetric primary particle size distribution and efficient deagglomeration behavior. Spray-drying submicrometric particles containing amorphous raloxifene hydrochloride were also produced by vibrational atomization. Controlled drug release profile was obtained for formulation containing polymer. Formulations were evaluated according to their in vitro lung deposition. They presented adequate pulmonary deposition, reaching the deepest stages of respiratory tract. Furthermore, a biodegradable subcutaneous implant containing raloxifene hydrochloride was developed by the manual compression of the powder produced by vibrational atomization spray-drying. The presence of the polymer [poly(ε-caprolactone)] and the oil (caprylic/capric triglyceride mixture) were essential to promote the in vitro drug release for 24 days. The powder for pulmonary route and the subcutaneous implant containing raloxifene hydrochloride enable to choose other routes of administration for this drug, which has a large first pass metabolism after oral administration. To evaluate the bioavailability of raloxifene hydrochloride, an analytical method was validated by high performance liquid chromatography, with low limit of quantification for the analysis of this drug in rat plasma. This method is applied in pharmacokinetic studies after pulmonary and subcutaneous administration of formulations developed in this work. Thus, the nanoencapsulation of raloxifene hydrochloride enabled a improved the antiproliferative effect on breast carcinoma cells and innovative formulations were produced from the vibrational atomization spray-drying

LC-UV method to assay raloxifene hydrochloride in rat plasma and its application to a pharmacokinetic study

A specific, precise, and accurate LC-UV method was developed and validated to assay raloxifene hydrochloride in rat plasma. Raloxifene was analyzed after liquid-liquid extraction and quantified by reversed phase liquid chromatography (C18 column) using acetonitrile and ammonium acetate buffer 0.05 M (pH 4.0) as mobile phase at a flow rate of 1 mL.min-1 and UV detection at 287 nm. Retention times of raloxifene and internal standard (dexamethasone) were approximately 11 min and 14 min, respectively. Linearity was checked for a concentration range between 25 ng.mL-1 and 1000 ng.mL-1. Intra- and inter-day precision had relative standard deviation lower than 10% and 15%, respectively. Recovery from plasma was higher than 90%. Accuracy values were 98.21%, 99.70%, and 102.70% for lower, medium, and upper limits of quantification, respectively. Limit of quantification was 25 ng.mL-1. Drug stability was analyzed at room temperature using plasma kept in a freezer at -80 °C for 45 days after processing for 6 h and three freeze-thaw cycles. The advantages of the method developed include stability under different conditions and low limit of quantification. Its applicability was confirmed by the analysis of raloxifene levels in plasma samples in a designed pharmacokinetic study in rats after intravenous administration (5 mg.kg-1)

Development and physicochemical characterization of dexamethasone-loaded polymeric nanocapsule suspensions

The influence of drug concentration, oil phase, and surfactants on the characteristics of dexamethasone-loaded nanocapsules was investigated. The best formulations were obtained at dexamethasone concentrations of 0.25 and 0.50 mg.mL-1 (encapsulation efficiency: 80-90%; mean size: 189–253 nm). The type of oil phase influenced only the stability of dexamethasone-loaded nanocapsules. The association of polysorbate 80 and sorbitan monooleate provided a more stable formulation. Sunflower oil and sorbitan sesquioleate used for the first time as oil phase and surfactant for nanocapsules, respectively, have allowed obtaining suspensions with low mean size and narrow size distribution

Development and physicochemical characterization of dexamethasone-loaded polymeric nanocapsule suspensions

The influence of drug concentration, oil phase, and surfactants on the characteristics of dexamethasone-loaded nanocapsules was investigated. The best formulations were obtained at dexamethasone concentrations of 0.25 and 0.50 mg.mL-1 (encapsulation efficiency: 80-90%; mean size: 189–253 nm). The type of oil phase influenced only the stability of dexamethasone-loaded nanocapsules. The association of polysorbate 80 and sorbitan monooleate provided a more stable formulation. Sunflower oil and sorbitan sesquioleate used for the first time as oil phase and surfactant for nanocapsules, respectively, have allowed obtaining suspensions with low mean size and narrow size distribution

LC-UV method to assay raloxifene hydrochloride in rat plasma and its application to a pharmacokinetic study

A specific, precise, and accurate LC-UV method was developed and validated to assay raloxifene hydrochloride in rat plasma. Raloxifene was analyzed after liquid-liquid extraction and quantified by reversed phase liquid chromatography (C18 column) using acetonitrile and ammonium acetate buffer 0.05 M (pH 4.0) as mobile phase at a flow rate of 1 mL.min-1 and UV detection at 287 nm. Retention times of raloxifene and internal standard (dexamethasone) were approximately 11 min and 14 min, respectively. Linearity was checked for a concentration range between 25 ng.mL-1 and 1000 ng.mL-1. Intra- and inter-day precision had relative standard deviation lower than 10% and 15%, respectively. Recovery from plasma was higher than 90%. Accuracy values were 98.21%, 99.70%, and 102.70% for lower, medium, and upper limits of quantification, respectively. Limit of quantification was 25 ng.mL-1. Drug stability was analyzed at room temperature using plasma kept in a freezer at -80 °C for 45 days after processing for 6 h and three freeze-thaw cycles. The advantages of the method developed include stability under different conditions and low limit of quantification. Its applicability was confirmed by the analysis of raloxifene levels in plasma samples in a designed pharmacokinetic study in rats after intravenous administration (5 mg.kg-1)

LC-UV method to assay raloxifene hydrochloride in rat plasma and its application to a pharmacokinetic study

A specific, precise, and accurate LC-UV method was developed and validated to assay raloxifene hydrochloride in rat plasma. Raloxifene was analyzed after liquid-liquid extraction and quantified by reversed phase liquid chromatography (C18 column) using acetonitrile and ammonium acetate buffer 0.05 M (pH 4.0) as mobile phase at a flow rate of 1 mL.min-1 and UV detection at 287 nm. Retention times of raloxifene and internal standard (dexamethasone) were approximately 11 min and 14 min, respectively. Linearity was checked for a concentration range between 25 ng.mL-1 and 1000 ng.mL-1. Intra- and inter-day precision had relative standard deviation lower than 10% and 15%, respectively. Recovery from plasma was higher than 90%. Accuracy values were 98.21%, 99.70%, and 102.70% for lower, medium, and upper limits of quantification, respectively. Limit of quantification was 25 ng.mL-1. Drug stability was analyzed at room temperature using plasma kept in a freezer at -80 °C for 45 days after processing for 6 h and three freeze-thaw cycles. The advantages of the method developed include stability under different conditions and low limit of quantification. Its applicability was confirmed by the analysis of raloxifene levels in plasma samples in a designed pharmacokinetic study in rats after intravenous administration (5 mg.kg-1)

Development and validation of RP-LC and uv spectrophotometric methods to assay bromopride in oral and injectable solutions

A reversed-phase liquid chromatographic (LC) and ultraviolet (UV) spectrophotometric methods were developed and validated for the assay of bromopride in oral and injectable solutions. The methods were validated according to ICH guideline. Both methods were linear in the range between 5-25 &#956;g mL-1 (y = 41837x - 5103.4, r = 0.9996 and y = 0.0284x - 0.0351, r = 1, respectively). The statistical analysis showed no significant difference between the results obtained by the two methods. The proposed methods were found to be simple, rapid, precise, accurate, and sensitive. The LC and UV methods can be used in the routine quantitative analysis of bromopride in oral and injectable solutions