The purpose of this study was to investigate the spray dried lactose as carrier for dry powder inhalation(DPI).The lactose particles were prepared by spray drying,then the particle size,shape and crystal form were characterized by laser diffraction,scanning electron microscopy(SEM),X-ray diffraction(XRD)and differential scanning calorimetry(DSC).The spray dried lactose particles were spherical and amorphous,but would transfer to crystal form when storage humidity was above 32%.Thus,the humidity of the storage environment should be controlled below 30%strictly in order to maintain the amorphous nature of spray dried lactose which is a great benefit to DPI development.
Linna WuXu MiaoZiyun ShanYing HuangLu LiXin PanQinghe YaoGe LiChuanbin Wu
To prepare a stable complex of doxycycline(Doxy)and hydroxypropy-β-cyclodextrin(HP-β-CD)for ophthalmic delivery,the optimum formulation and preparation conditions were investigated using response surface methodology(RSM),artificial neural network(ANN)and support vector machine(SVM)modeling.The molar ratios of HP-β-CD/Doxy and Mg^(2+)/Doxy,inclusion time and temperature were selected as independent variables (X_(1)-X_(4)) and inclusion efficiency and stability of the Doxy-HP-β-CD complex were selected as dependent(response)variables(Y_(1) and Y_(2)).The optimal formulation predicted by genetic algorithm(GA)combined with the models was characterized by microscopy and nuclear magnetic resonance spectrometry,and the stability of Doxy in the complex was evaluated.The highest values of Y_(1) and Y_(2) were obtained using an ANN model combined with GA which predicted the values of X_(1)-X_(4) to be 4,10.8,12 h and 25℃,respectively.The modeling and optimization results indicated that a feed-forward back-propagation ANN with one hidden layer and 10 hidden units showed better fitting to both responses compared to the RSM and SVM models.GA proved to be an efficient tool in multiobjective optimization of a pharmaceutical formulation.
Solid dispersion of calcitriol with lipophilic surfactants and triglycerides was developed by melt-mixing method to modify the release and enhance stability of the drug.The solid dispersions were characterized by differential scanning calorimetry(DSC),hot stage polarized optical microscopy(HSPM),infrared spectroscopy(FTIR)and stability studies.The solid dispersion significantly enhanced the stability of calcitriol,which could be attributed to the high antioxidant activity of the solid lipid dispersion.The rapid dissolution rate from the solid dispersion was attributed to the amorphous or solid solution state of drug with improved specific surface area and wettability than the drug crystals.Therefore,solid dispersion of calcitriol with D-a-tocopheryl polyethylene glycol 1000 succinate(TPGS)offers a good approach to modify the release and enhance stability of calcitriol.The influence of lipophilic solid dispersion on drug bioavailability needs further investigation.
