ABSTRACT Background: Tretinoin and 5-fluorouracil are indicated for treatment of various skin disorders and actinic keratosis respectively. Objective: Present study was focused to design liposomes containing 5- fluorouracil and tretinoin. Design was further optimized by 32 full factorial design. Methods: Liposomes were prepared by ethanol injection method and evaluated by Transmission Electron Microscopy, percentage entrapment efficiency, zeta potential and in vitro drug release. Optimized formulation was subjected to histopathological and stability studies at 4ºC, 25ºC and 60ºC temperatures. Results: No drug crystals were visible in transmission electron microscopy, regardless of the preparation technique or the loaded drug. Formulation F9 showed maximum drug entrapment of 72.86% and 69.70% for 5-fluorouraciland tretinoin respectively. When phospholipid concentration was increased from 40 to 60 mg/ml, encapsulation efficiencies of formulation increased. Zeta potential and particle size were maintained within range of -19.14 to -25.61 and 100 to 200 nm respectively which facilitated good stability and penetration of liposomes. Dissolution profiles of formulations F1 to F6 showed high amount of drug release (30.6 to 67.42%) at 2 h. Liposomes were not stable at high temperature but formulations were most stable when stored at lower temperature i.e. 4oC. Conclusion: So, in liposomes both 5-fluorouracil and tretinoin were successfully incorporated and it can be further used for formulation development.

RESUMEN Objetivo: El presente estudio se centró en el diseño de liposomas que contenían 5-fluorouracilo y tretinoína. El diseño fue optimizado por 32 diseño factorial completo. Metodos: Los liposomas se prepararon mediante el método de inyección de etanol y se evaluaron mediante Microscopía Electrónica de Transmisión, % de eficiencia de encapsulación, potencial zeta y liberación de fármaco in vitro. La formulación optimizada se sometió a estudios histopatológicos y de estabilidad a temperaturas de 4ºC, 25ºC y 60ºC. Resultados: Ningún cristal de los fármacos era visibles en el Microscopía Electrónica de Transmisión, sin importar la técnica de la preparación o el fármaco cargado. La formulación F9 demostró el atrapamiento máximo del fármaco del 72,86% y del 69,70% para 5-fluorouracilo y tretinoína respectivamente. Cuando la concentración del fosfolípido fue aumentada a partir de 40 a 60 mg/ml, las eficiencias de encapsulación de la formulación aumentaron. El potencial de zeta y el tamaño de partícula fueron mantenidos dentro de la gama de-19,14 a -25,61 y 100 a 200 nanómetros respectivamente, que facilitó la buena estabilidad y la penetración de liposomas. Los perfiles de disolución de las formulaciones F1 a F6 mostraron una alta cantidad de liberación de fármaco (30,6 a 67,42%) a las 2h. Los liposomas no eran estables a alta temperatura, pero las formulaciones eran más estables cuando se almacenaban a una temperatura más baja, es decir, 4 ºC. Conclusiones: Así, en los liposomas, tanto los fármacos 5-fluorouracilo como los tretinoína se incorporaron con éxito y se pueden utilizar para el desarrollo de la formulación.

O trabalho teve como objetivo o desenvolvimento de novas cápsulas com revestimento entérico HPMC (ECHC) conectadas com microesponjas carregadas com fluoruracila (5-FU) em combinação com grânuos de pectinato de cálcio. O método de difusão de solvente modificado quasi-emulsão foi usado para formular microesponjas com base no planejamento fatorial 32 e determinaram-se os efeitos das variáveis independentes (volume de solvente orgânico e conteúdo Eudragit RS100) sobre as variáveis dependentes (tamanho de partícula, EE% e % CDR). As microesponjas otimizadas (F4) foram caracterizadas por SEM, PXRD, TGA e ligadas aos grânulos de pectinato de cálcio em cápsulas de HPMC e estas foram, ainda, revestidas com polímero entérico Eudragit L 100 (Ed-L100) e/ou Eudrgit S 100 (Ed S 100) em diferentes proporções. No estudo de liberação in vitro de ECHC foi realizada em vários meios de liberação sequencial SGF durante 2 h, seguido de SIF para as próximas 6 h, e, em seguida, em SCF (na presença e na ausência de enzima pectinase por mais 16 h). A liberação do fármaco foi retardada em revestimento com a EDS-100, em comparação com mistura de EDS-100: EDL-100, de revestimento. O percentual de 5-FU liberado de ECHC 3 ao final de 24 h foi 97,83 ± 0,12% em presença de pectinase, enquanto que para o controle foi de 40,08 ± 0,02% do fármaco. A formulação otimizada foi submetida a estudos Roentgenográficos in vivo, em coelhos brancos Nova Zelândia, para analisar o comportamento das cápsulas desenvolvidas direcionadas ao cólon. Os estudos de farmacocinética em coelhos brancos da Nova Zelândia foram conduzidos para determinar a extensão da exposição sistêmica propiciada pela formulação desenvolvida, em comparação com solução aquosa de 5-FU. Assim, cápsulas entéricas de HPMC revestidas e conectadas com microesponjas carregadas com 5-FU e grânulos de pectinato de cálcio se mostraram promissoras como formulação para liberação do fármaco no cólon no tratamento do câncer colorretal.

The work was aimed at developing novel enteric coated HPMC capsules (ECHC) plugged with 5 Florouracil (5-FU) loaded Microsponges in combination with calcium pectinate beads. Modified quasi-emulsion solvent diffusion method was used to formulate microsponges based on 32 factorial design and the effects of independent variables (volume of organic solvent and Eudragit RS100 content) on the dependent variables (Particle size, %EE & % CDR) were determined. The optimized microsponges (F4) were characterized by SEM, PXRD, TGA and were plugged along with calcium pectinate beads in HPMC capsules and the HPMC capsules were further coated with enteric polymer Eudragit L 100 (Ed-L100) and/ or Eudrgit S 100 (Ed-S 100) in different proportions. In vitro release study of ECHC was performed in various release media sequentially SGF for 2 h, followed by SIF for the next 6 h and then in SCF (in the presence and absence of pectinase enzyme for further 16 h). Drug release was retarded on coating with EdS-100 in comparison to blend of EdS-100: EdL-100 coating. The percentage of 5-FU released at the end of 24 h from ECHC 3 was 97.83 ± 0.12% in the presence of pectinase whereas in control study it was 40.08 ± 0.02% drug. The optimized formulation was subjected to in vivo Roentgenographic studies in New Zealand white rabbits to analyze the in vivo behavior of the developed colon targeted capsules. Pharmacokinetic studies in New Zealand white rabbits were conducted to determine the extent of systemic exposure provided by the developed formulation in comparison to 5-FU aqueous solutions. Thus, enteric coated HPMC capsules plugged with 5-FU loaded microsponges and calcium pectinate beads proved to be promising dosage form for colon targeted drug delivery to treat colorectal cancer.

O presente trabalho compreendeu estudo de um novo sistema de liberação prolongada de cloridrato de prometazina (PHC) com polímeros acrílicos Eudragit RL100 e Eudragit S100 em diferentes proporções em massa (1:1 e 1:5) e em combinação (0,5+1,5), utilizando técnicas de liofilização e de secagem por aspersão As dispersões sólidas foram caracterizadas por espectrofotometria no infravermelho por transformada de Fourier (FT-IR), calorimetria diferencial de varredura (DSC), difratometria de raios X (PXRD), Ressonância Magnética Nuclear (RMN), microscopia eletrônica de varredura (SEM) e, também, por estudos de solubilidade e de dissolução in vitro em HCl 0,1 N (pH 1,2), água bidestilada e tampão fosfato (pH 7,4). Realizaram-se, também, testes de adsorção da solução do fármaco nos polímeros sólidos. Desenvolveu-se sistema de dispersão sólida exclusiva dentro das cápsulas, que foi avaliado por meio de estudos de dissolução in vitro. Relacionou-se o desaparecimento progressivo de picos do fármaco em perfis termotrópicos de dispersões secas por spray à quantidade aumentada de polímero, enquanto os estudos de SEM sugeriram dispersão homogênea do fármaco no polímero. O Eudragit RL100 apresentou maior capacidade de adsorção do que o Eudragit S100 e, dessa forma, a combinação de (0,5+1,5) para S100 e para RL100 mostrou taxa de dissolução maior, com liberação de 94,17% de fármaco em 12 horas. Entre as várias formulações, as cápsulas preparadas pela combinação de polímeros acrílicos utilizando secagem por aspersão (0,5+1,5) apresentou liberação prolongada do fármaco em 12 horas, com 96,78% de liberação, seguindo cinética de ordem zero (r² = 0,9986)

The present study investigated a novel extended release system of promethazine hydrochloride (PHC) with acrylic polymers Eudragit RL100 and Eudragit S100 in different weight ratios (1:1 and 1: 5), and in combination (0.5+1.5), using freeze-drying and spray-drying techniques. Solid dispersions were characterized by Fourier-transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), Powder X-ray diffractometry (PXRD), Nuclear magnetic resonance (NMR), Scanning electron microscopy (SEM), as well as solubility and in vitro dissolution studies in 0.1 N HCl (pH 1.2), double-distilled water and phosphate buffer (pH 7.4). Adsorption tests from drug solution to solid polymers were also performed. A selected solid dispersion system was developed into capsule dosage form and evaluated for in vitro dissolution studies. The progressive disappearance of drug peaks in thermotropic profiles of spray-dried dispersions were related to increasing amount of polymers, while SEM studies suggested homogenous dispersion of drug in polymer. Eudragit RL100 had a greater adsorptive capacity than Eudragit S100, and thus its combination in (0.5+1.5) for S100 and RL 100 exhibited a higher dissolution rate with 97.14% drug release for twelve hours. Among different formulations, capsules prepared by combination of acrylic polymers using spray-drying (1:0.5 + 1.5) displayed extended release of drug for twelve hours with 96.87% release followed by zero order kinetics (r²= 0.9986).