Distribution of effervescent inhalable nanoparticles after pulmonary delivery: an in vivo study.

BACKGROUND: Effervescent inhalable nanoparticles (NPs) have previously been shown to be a promising alternative to conventional lung cancer treatment in animals. This study investigates the biodistribution of effervescent inhalable NPs after a single dose administration via pulmonary route in lung cancer-bearing mice. METHODS & RESULTS: Whole-body autoradiography and confocal laser-scanning microscopy (CLSM) were used to investigate the distribution of inhalable NPs loaded in an effervescent microcarrier. Inhalable doxorubicin-loaded NPs were tagged with 14C for whole-body autoradiography, or with fluorescein isothiocyanate for CLSM imaging. After pulmonary delivery, NPs were widely disseminated in the lungs with a long retention time (24 h). The heart was radioactivity free at all time points of the study. CLSM images showed that inhalable NPs were taken up by cells and that doxorubicin was released to the cell nuclei. CONCLUSION: This is the first study to investigate the distribution of inhalable NPs in a lung cancer-bearing animal model. Inhalable NPs achieved deep lung deposition, were actively released from microcarrier particles, spread to different parts of the lung and released doxorubicin in vivo. These NP characteristics contribute to the efficacy of effervescent inhalable NPs as a lung cancer treatment.

Microcalorimetric method to assess phagocytosis: macrophage-nanoparticle interactions.

This study evaluated the use of isothermal microcalorimetry (ITMC) to detect macrophage-nanoparticle interactions. Four different nanoparticle (NP) formulations were prepared: uncoated poly(isobutyl cyanoacrylate) (PIBCA), polysorbate-80-coated PIBCA, gelatin, and mannosylated gelatin NPs. Changes in NP formulations were aimed to either enhance or decrease macrophage-NP interactions via phagocytosis. Alveolar macrophages were cultured on glass slabs and inserted in the ITMC instrument. Thermal activities of the macrophages alone and after titration of 100 µL of NP suspensions were compared. The relative interactive coefficients of macrophage-NP interactions were calculated using the heat exchange observed after NP titration. Control experiments were performed using cytochalasin B (Cyto B), a known phagocytosis inhibitor. The results of NP titration showed that the total thermal activity produced by macrophages changed according to the NP formulation. Mannosylated gelatin NPs were associated with the highest heat exchange, 75.4 ± 7.5 J, and thus the highest relative interactive coefficient, 9,269 ± 630 M-1. Polysorbate-80-coated NPs were associated with the lowest heat exchange, 15.2 ± 3.4 J, and the lowest interactive coefficient, 890 ± 120 M-1. Cyto B inhibited macrophage response to NPs, indicating a connection between the thermal activity recorded and NP phagocytosis. These results are in agreement with flow cytometry results. ITMC is a valuable tool to monitor the biological responses to nano-sized dosage forms such as NPs. Since the thermal activity of macrophage-NP interactions differed according to the type of NPs used, ITMC may provide a method to better understand phagocytosis and further the development of colloidal dosage forms.

Inhalable nanoparticles, a non-invasive approach to treat lung cancer in a mouse model.

Doxorubicin-loaded nanoparticles (NPs) were incorporated into inhalable effervescent and non-effervescent carrier particles using a spray-freeze drying technique. The prepared inhalable powders were tested in a tumor bearing Balb/c mouse model. Control mice were treated with blank inhalable NPs, inhalable lactose powder containing free doxorubicin, and intravenous injections of a suspension of doxorubicin NPs, doxorubicin solution, or saline solution. The survival of treatment groups was plotted with Kaplan-Meier curves. Animals treated with inhalable effervescent nanoparticle powder containing 30µg doxorubicin showed a highly significant improvement in survival compared to all other treatment groups. Mice in control groups treated with doxorubicin solution or doxorubicin NPs as intravenous injection, died in less than 50 days. Inhalable free doxorubicin showed high cardiac toxicity. Pathological samples showed large tumor masses in the lungs of animals not treated or treated with i.v. injections of doxorubicin NPs or doxorubicin solution. The lungs of animals treated with inhalable effervescent doxorubicin NPs showed fewer and much smaller tumors compared to the control groups, as visualized by MRI imaging which confirmed the observed pathology results. The present study demonstrates that inhalable effervescent doxorubicin NPs are an effective way to treat lung cancer. This non-invasive route of administration might change the way lung cancer is treated in the future.

Pulmonary delivery of inhalable nanoparticles: dry powder inhalers.

Pulmonary administration of inhalable nanoparticles (NPs) is an emerging area of interest. Dry powder inhalers may offer particular advantages for pulmonary administration of NPs. This article reviews research performed on the formulation of inhalable NPs as dry powder to achieve deep-lung deposition and enhance NP redispersibility. Moreover, the article summarizes up-to-date in vivo applications of inhalable NPs as dry powder inhalers.

Isothermal microcalorimetry as a quality by design tool to determine optimal blending sequences.

This study was designed to assess the value of isothermal microcalorimetry (ITMC) as a quality by design (QbD) tool to optimize blending conditions during tablet preparation. Powder mixtures that contain microcrystalline cellulose (MCC), dibasic calcium phosphate dihydrate (DCPD), and prednisone were prepared as 1:1:1 ratios using different blending sequences. ITMC was used to monitor the thermal activity of the powder mixtures before and after each blending process. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) were performed on all final powder mixtures. Final powder mixtures were used to prepare tablets with 10 mg prednisone content, and dissolution tests were performed on all tablet formulations. Using ITMC, it was observed that the powder mixtures had different thermal activity depending on the blending sequences of the ingredients. All mixtures prepared by mixing prednisone with DCPD in the first stage were associated with relatively fast and significant heat exchange. In contrast, mixing prednisone with MCC in the first step resulted in slower heat exchange. Powder mixture with high thermal activity showed extra DSC peaks, and their dissolution was generally slower compared to the other tablets. Blending is considered as a critical parameter in tablet preparation. This study showed that ITMC is a simple and efficient tool to monitor solid-state reactions between excipients and prednisone depending on blending sequences. ITMC has the potential to be used in QbD approaches to optimize blending parameters for prednisone tablets.

Thermal treating of acrylic matrices as a tool for controlling drug release.

The purpose of the present study was to investigate the effect of thermal-treating on the release of ibuprofen from the granules prepared using aqueous dispersions of Eudragit. To accomplish this goal, different formulations were prepared using wet granulation method containing two different types of Eudragit aqueous dispersions, RS30D, RL30D and Avicel as filler. Tablets were prepared using direct compression method. The prepared tablets were thermally treated at 50 and 70 degrees C for 24 h. The drug release from tablets was assessed before and after thermal-treating. The results of release study showed that, thermally-treating the tablets at the temperatures higher than glass transition temperature (Tg) of the polymer can decrease the drug release from matrices. For mechanistic evaluation of the effect of thermal-treating, powder X-ray diffraction (XPD), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), Fourier transform infrared (FT-IR) and helium pycnometer have been employed. The SEM graphs showed that the tablets have smoother surface with less porosity after thermal-treating. FT-IR spectra showed no change in the spectrum of thermally-treated tablet compared to control. In DSC graphs, no crystalline change was seen in the heat-treated samples of ibuprofen tablets, but decreased and widened peak size were related to the probable formation of solid solution of ibuprofen in Eudragit matrix. The results of helium pycnometer showed a significant decrease in the total porosity of some heat-treated samples. This study revealed the importance of thermal treating on the drug release from sustained release tablets containing Eudragit polymer.