ABSTRACT
Drug solubility poses numerous challenges in design of formulations for drugs with poor aqueous solubility. Ethionamide is an antitubercular drug belonging to biopharmaceutical classification system class II drug having less aqueous solubility. Nanosuspensions were prepared by using various solvents such as methanol, ethanol, acetone and chloroform and it was prepared using anti-solvent precipitation technique by using probe sonication. Various stabilizers such as tocopherolpolythytlene glycol succinate, polyvinylpyrrolidone and tween 80 singly or in combination were studied. A 32 factorial design was employed to study the effect of independent variables, concentration of stabilizers and stirring speed on particle size and cumulative percent drug release. The particle size of the optimized batch was 97.54 ± 8.47 nm with polydispersity index of 0.36 and zeta potential -10.1 ± 2.3 mV. The cumulative percent drug release of optimized batch was found to be 95.01 ± 1.16% in 60 min. Optimized batch was ultracentrifuged and evaluated for saturation solubility studies, stability and powder X-ray Diffraction studies. Optimized nanosuspension was loaded on Espheres by spraying in a coating pan and then coating of Eudragit controlled release polymers. The coated Espheres were evaluated for drug content, friability, scanning electron microscopy, ex-vivo permeation studies and drug release kinetics studies. The friability value for primary coated sphere was found to be 0.8 ± 0.12% and for secondary was 1% and the best fit model was found to be Korsmeyer-Peppas model which is indicative of diffusion controlled release. Ex vivo diffusion studies revealed a moderate increase in permeability.
ABSTRACT
The main aim of this study was to develop a multiparticulate system containing mini-tablets of omeprazole formulated with an enteric polymer with pH-dependent solubility. Pre-formulation studies showed good flow and compaction capacity, leading to the production ofhigh quality mini-tablets. The mini-tablets were coated in a fluidized bed with hydroxypropylmethylcellulose /Eudragit(r) L30D55 and packed into hard gelatin capsules. The dissolution profile showed gastro-resistance and zero-order kinetics. The dissolution profile for the formulation containing lactose as the diluent and coated with 12% (tablet weight gain) of polymer was similar to that ofthe reference drug.
O presente trabalho teve como objetivo desenvolver e avaliar um sistema multiparticulado de liberação modificada, composto por mini-comprimidos revestidos com polímero de liberação pH-dependente, utilizando como fármaco modelo o omeprazol. Os mini-comprimidos (diâmetro de 2,5 mm) foram obtidos em máquina de compresssão excêntrica, revestidos em leito fluidizado com hidroxipropilmetilcelulose/Eudragit(r)L30D55 e, em seguida, acondicionados em cápsulas gelatinosas duras. A partir dos resultados obtidos no perfil de dissolução foi possível demonstrar a liberação gastro-resistente e comportamento cinético de ordem zero. A formulação contendo lactose como diluente, com revestimento de 12% de polímero, demonstrou semelhança com o medicamento referência.
Subject(s)
Tablets, Enteric-Coated/analysis , Omeprazole/pharmacokinetics , Dissolution/analysisABSTRACT
An oral controlled onset dosage form intended to approximate the chronobiology of rheumatoid arthritis was proposed for colonic targeting. The multiparticulate system comprising of non-pareil seeds coated with Eudragit S100 was designed for chronotherapeutic delivery of valdecoxib. The drug was coated onto non-pareil seeds by powder layering technique using the conventional coating pan. Different coat weights of non-aqueous dispersions were applied onto the drug-coated pellets using spray coating technique. In vitro dissolution tests of the coated pellets were performed in different pH media for a period of 11 hours. The in-vitro dissolution tests showed that the release of valdecoxib from the coated pellets depended on the pH of the dissolution fluid and the coat weights applied. All the formulations exhibited no release of drug in the pH 1.2 and pH 4 buffers; drug release took place in phosphate buffer of pH 7.4. Further intactness of the drug in the formulation and the uniformity of the polymer coating were checked by the infrared study and scanning electron microscopy. Stability studies inferred that the drug undergoes no considerable degradation pattern at room temperature and 40oC even after three weeks. All the above results show that the formulation could be highly advantageous in the chronotherapy of rheumatoid arthritis with appreciable drug release and physiochemical properties.