RESUMEN
Objective: To optimize the formula of memantine hydrochloride sustained release pellets and investigate the drug release in vitro.Methods: Memantine hydrochloride sustained release pellets were prepared by a fluidized bed.The factors such as inlet air temperature, spray pressure and feeding rate were optimized by orthogonal tests.The Box-Behnken response surface methodology was used to screen the major influencing factors (ethyl cellulose aqueous dispersion, PEG 6000 and the coating weight) in the release of memantine hydrochloride.The coating formula and coating weight were optimized with the cumulative release rate of memantine hydrochloride in 2, 6,and 12 h as the response values.The drug release in vitro was also studied.Results: The optimum preparation parameters of the pellets were as follows: the inlet air temperature of 45℃, the spray pressure of 1.0 bar, and the feeding rate of 1.5 r·min-1.The best sustained release coating formula was as follows: the content of ethyl cellulose aqueous dispersion of 8.4%, the content of PEG 6000 of 2.3%, and the weight gain of sustained release layer of 16.7%.The memantine hydrochloride sustained release pellets had notable sustained release effect.Conclusion: Orthogonal tests and Box-Behnken response surface method can be used for the formula optimization of memantine hydrochloride sustained-release pellets.The established fitting model is simple with good predictability.
RESUMEN
La optimización de los medios de cultivo con fines industriales en la mayoría de los casos ha sido efectuada mediante procedimientos empíricos de ensayo y error. Empleando diversos métodos estadísticos es probable que el medio de cultivo original pueda ser optimizado, en muchos casos es posible obtener un medio que no solo sea más productivo, sino de menor o igual costo que el original. Se optimizó el medio de cultivo QBP para el crecimiento de las cepas del consorcio bacteriano BIOYAF capaz de degradar hidrocarburos del petróleo, empleando un Diseño de Factor Categórico Individual para determinar el tiempo de trabajo, un Diseño Factorial (24) para determinar los rangos de trabajo de concentración de los nutrientes y un Diseño de Superficie de Respuesta para optimizar las concentraciones. Las variables de respuesta de evaluación de los experimentos fueron masa húmeda, masa (UDO), conteo de viables, conductividad, pH y tensión superficial. El tiempo óptimo para el crecimiento de las cepas del consorcio BIOYAF es de seis horas. El medio de cultivo QBP con concentraciones óptimas de fosfato de amonio (3,19 g.L-1), sulfato de magnesio (0,04 g.L-1), levadura (3,77 g.L-1) y sacarosa (47,89 g.L-1) permite que la producción de biomasa aumente de 1,540 UDO a 3,082 UDO.
The optimization of culture media with industrial purposes, in most cases, has been made through empirical trial and error procedures. Using different statistical methods original culture media can be optimized, in many cases, is possible to obtain a more productive media, at the same cost as the original one. The culture media QBP was optimized for the growth of the bacterial consortium BIOYAF, which can degrade petroleum hydrocarbons, using a Categorical Individual Factor Design to determine the working time, a Factorial Design (24) to determine working range of elements concentration and a Surface Response Design to optimize the concentrations. The response variables of the experiments used in this work were: wet mass, mass (UDO), viable's count, conductivity, pH and surface tension. The optimal time for growth of the consortium was of six hours. The optimized QBP culture media (ammonium phosphate: 3.19; magnesium sulphate: 0,04; yeast extract : 3,77; sucrose: 47,89) allowed that the biomass' production increases of 1,540 UDO to 3,082 UDO.