ABSTRACT
The size and surface morphology of carrier lactose had influence on the aerosolization performance of dry powder inhalers. In this article, chlorpheniramine maleate was blended with two types of commercial carrier lactose, which were Lactohale 100® and Respitose SV003® (SV003), as formulation model. In vitro experiments were conducted using fast screening impactor at 30 L·min-1 and 60 L·min-1 respectively. Meanwhile, computational fluid dynamics (CFD) coupling with discrete element modelling (DEM) was applied to discuss the movements of those two carrier particles in Handihaler® at the flow rate mentioned above. The dispersion characteristics of two formulations and the dispersion mechanism of Handihaler® were analyzed by establishing the relationship between in vitro experiments and numerical simulation. The results of in vitro experiments and CFD-DEM demonstrated that the aerosolization performance of formulation with SV003 was better. The linear correlation (R2 = 0.940 1) between fine particle dose and total energy loss by carrier collision within the wall of device was found by comparing the in vitro experimental results with CFD-DEM results. It revealed that particle-wall collision in Handihaler® had direct impact on the dispersion results of formulation.
ABSTRACT
Melatonin (MLT) is an endogenous chemical that has antitumor effects at high doses. However, it shows low oral bioavailability and short in vivo half-life, leading to drug resistance. Here, liposomal melatonin dry powder inhalers (LMD) were prepared, and were used for treatment of primary rat lung cancer by pulmonary delivery. Liposomal melatonin (LM) was prepared by the ethanol injection method to achieve an entrapment efficiency of 98.89%. LMD was obtained by freeze-drying after LM was mixed with mannitol. LMD appeared as spherical particles under a scanning electron microscope. The rehydrated liposomes had a small size of 65.15 nm and the zeta potential of -14.2 mV without change inentrapment efficiency. LMD had an aerodynamic particle size of 6.73 ± 0.012 μm and a fine particle fraction (FPF<8.06 μm) of 22.2%, suitable for pulmonary delivery. When administered with the same dose, LMD showed much higher inhibition on A549 lung cancer cells than MLT and gemcitabine. LMD of a large dose had no effect on the growth of normal lung epithelial cells (BEAS-2B). Rat lung cancer models were established after 45 days by instilling 3-methylcholanthrene (MCA) and N,N-dimethylnitrosamine (DEN) into the rat lungs once (the experiments had been approved by the ethics committee and carried out in accordance with relevant guidelines and regulations). Decreases of tumor nodules and inflammatory cells in the tumor-bearing rat lungs were observed after treatment of MLT, gemcitabine and LMD by pulmonary delivery compared with the models, wherein LMD was most effective. The efficiencies of inhibition of NF-κB p65, increase of Tunel detection (indicating enhancement of apoptosis), and decrease of malondialdehyde corresponded to LMD being most effective. Therefore, given the fact that LMD can deliver the drug into the tumor tissues of lungs, and it presents as a promising pulmonary inhalable regiment for treatment of lung cancer.