Nanoparticle-containing lyophilized dry powder inhaler formulations optimized using central composite design with improved aerodynamic parameters and redispersibility

Objectives: The aim of this study was to improve the aerodynamic behavior and redispersibility of a lyophilized dry powder inhaler (DPI) formulation containing nanoparticles.Methods: Paclitaxel (PTX)-human serum albumin (HSA) nanoparticles were used as a model, and DPIs containing the nanoparticles were produced by lyophilization using different carriers and carrier ratios. A central composite design was employed to optimize the formulation. L-leucine and mannitol were chosen as independent variables, and mass median aerodynamic diameter (MMAD), emitted fraction, fine particle fraction (FPF), nanoparticle size, polydispersity index (PDI), zeta potential were selected as dependent variables.Results: The water content of DPIs was less than 5% for all DPIs. The cytotoxicity of the DPIs, determined using A549 cells, was due to PTX alone. Particle sizes of 204.3 ± 1.65 nm and 94.3-1353.0 nm were obtained before and after lyophilization, respectively. The developed method resulted in a reduction in the MMAD from 8.148 µm to 5.274 µm, an increase in the FPF from 17.63% to 33.60%, and an increase in the emitted fraction from 77.68% to 97.03%. The physico-chemical characteristics of the optimized formulation were also assessed.Conclusions: In conclusion, this study demonstrates that lyophilization can be used to produce nanoparticle-containing DPI formulations with improved redispersibility and aerodynamic properties.

Comparative evaluation of cost for preliminary and tertiary municipal wastewater treatment plants in Istanbul

As the global economy continues to grow, the need for an economic evaluation of wastewater treatment plants (WWTPs) is increasing. Determination of cost functions (CFs) helps to assess the costs of WWTP and to be able to reach to the satisfactory financial levels of construction and operation practices in the early phases of a project. In this study, unit capital and operation and maintenance (O&M) costs were calculated by analyzing the real capital and operation and maintenance expenditures of 16 full-scale WWTPs in Istanbul. Besides, the impacts of treatment level and capacity on costs were investigated. The unit total capital cost was found as 0.013 ± 0.004 €/m³ and 0.054 ± 0.009 €/m³ for preliminary and tertiary treatment, respectively, whereas the unit total O&M cost were 0.011 ± 0.007 €/m³ and 0.077 ± 0.021 €/m³ for preliminary and tertiary treatment, respectively. Capital (investment) costs covered 58% of the total cost in preliminary WWTPs, whereas; O&M costs had the highest share (58%) in tertiary WWTPs. The results of this study confirmed that the level of treatment considerably affected the costs of WWTPs. Moreover, the CFs were separately derived for tertiary treatment including A²O with and without digester. The CFs obtained in this study are of utmost importance to be used in the economic evaluation of the planned WWTPs and in the management of existing ones.

Development and characterization of metformin hydrochloride- and glyburide-containing orally disintegrating tablets

Diabetes is characterized by chronic hyperglycemia. Although metformin hydrochloride (MHCl)- and glyburide (GLB)-containing conventional tablets are available in the market and used to treat diabetes, orally disintegrating tablets (ODTs) containing the combination of these drugs are not commercially available. Therefore, the aim of this study was to prepare ODTs containing MHCl and GLB by direct-compression (DC-ODTs) and freeze-drying (FD-ODTs) methods. Physical properties of the powder mixture of DC-ODT formulation were determined (Angle of repose: 37.18 ± 1.27°; compressibility index: 20.31 ± 1.06%; Hausner ratio: 1.25 ± 0.03). Its moisture content was 0.3 ± 0.09%. The hardness values and the disintegration times for DC-ODTs and FD-ODTs were 221.60 ± 40.82 and 66.54 ± 2.68 N, and 80 and 30 s, respectively. Friability values were 0.24% for DC-ODTs and 0.38% for FD-ODTs. In uniformity-of-mass for single-dose-preparations test, the average weight was 684.38 ± 1.97 mg for DC-ODTs and 342.93 ± 2.4 mg for FD-ODTs, with less than 5% deviation for all 20 tablets. Water-absorption ratio for DC-ODTs was 1.30 ± 0.05. More than 90% of MHCl and GLB were dissolved within 5 min in both DC-ODTs and FD-ODTs. Although Caco-2 permeability of MHCl was influenced by the ODTs, GLB permeability was not. These results indicated that MHCl- and GLB-containing ODTs may be used as promising formulations for the treatment of diabetes.