Respirable Powder Formulation Research Articles

Novel inhalable powder formulation of pirfenidone with sustained release properties to improve pulmonary deposition

The aim of this study was to develop a new respirable powder (RP) formulation of pirfenidone (PFD) with sustained release properties to ameliorate the pharmacokinetic drawbacks of the previously-developed PFD-RP on rapid elimination from the lung after insufflation. Based on screenings using several polymers, Kollidon® SR was chosen to produce a solid dispersion of PFD with sustained release properties (SRSD/PFD), and an RP formulation of SRSD/PFD (SRSD/PFD-RP) was prepared. Characteristics of SRSD/PFD-RP were examined in terms of biopharmaceutical, pharmacological, and phototoxic properties. In laser diffraction analysis, SRSD/PFD-RP could be dispersed to SRSD/PFD and lactose carrier particles, and SRSD/PFD in SRSD/PFD-RP had suitable particle sizes for inhalation. Insufflated SRSD/PFD-RP (0.03 mg-PFD/rat) showed a prolonged elimination half-life and mean residence time of PFD since these values were approximately 3.7-fold higher than those of insufflated PFD-RP (0.3 mg-PFD/rat: a pharmacologically-effective dose). Insufflated SRSD/PFD-RP (0.03 mg-PFD/rat) showed a similar anti-inflammatory potential in the lung of antigen-evoked lung inflammatory models compared with insufflated PFD-RP (0.3 mg-PFD/rat). Obvious skin phototoxicity was negligible after insufflation of SRSD/PFD-RP (0.03 mg-PFD/rat). In conclusion, SRSD/PFD-RP would be an attractive dosage form for an inhalation system of PFD and contribute to PFD medication for idiopathic pulmonary fibrosis with high efficacy and safety.

Novel approach for attenuation of pirfenidone-induced digestive symptoms: a respirable powder formulation of pirfenidone.

Aim: Orally taken pirfenidone (PFD) often causes digestive symptoms. A respirable powder formulation of PFD (PFD-RP) was previously developed, and this study aimed to verify the risk of digestive symptoms after insufflation of PFD-RP. Materials & methods: Intestinal motility and gastrointestinal exposure levels was evaluated in PFD-RP (0.3-mg PFD/rat: a pharmacologically effective dose) and orally taken PFD (10-100mg/kg) groups. Results & conclusion: Orally taken PFD at doses above 30mg/kg significantly inhibited intestinal motility. In contrast, insufflated PFD-RP led to comparable intestinal motility in control group, and gastrointestinal exposure levels in PFD-RP group were markedly lower than those in orally taken PFD groups. Inhalation therapy using PFD-RP may be efficacious to reduce the risk of digestive symptoms frequently induced by orally taken PFD.

副作用リスク低減ならびに肺局所作用持続を指向した新規 pirfenidone 徐放性粉末吸入製剤の開発

副作用リスク低減ならびに肺局所作用持続を指向した新規 pirfenidone 徐放性粉末吸入製剤の開発

Respirable powder formulation of a shortened vasoactive intestinal peptide analog for treatment of airway inflammatory diseases.

The aim of present study was to develop a respirable powder (RP) of a shortened vasoactive intestinal peptide (VIP) analog for inhalation. VIP and C-terminally truncated VIP analogs were synthesized with a solid-phase method. A structure-activity relationship (SAR) study was carried out in terms with binding and relaxant activities of the peptides. Prepared RP formulation of a shortened VIP analog was physicochemically characterized by morphological, in vitro aerodynamic, and pharmacological assessments. The SAR study demonstrated that the N-terminal 23 amino acid residues were required for biological activity of VIP. Upon chemical modification of VIP(1-23), [R15, 20, 21 , L17 ]-VIP(1-23) was newly developed, which had higher binding activity in rat lung and smooth muscle relaxant effect in mouse stomach than VIP(1-23). The [R15, 20, 21 , L17 ]-VIP(1-23)-based RP, [R15, 20, 21 , L17 ]-VIP(1-23)/RP, exhibited fine in vitro inhalation performance. Airway inflammation evoked by sensitization of antigen in rats was attenuated by pre-treatment with the [R15, 20, 21 , L17 ]-VIP(1-23)/RP at a dose of 50μg-[R15, 20, 21 , L17 ]-VIP(1-23)/rat as evidenced by a 70% reduction of recruited inflammatory cells in bronchoalveolar lavage fluid. On the basis of these results, [R15, 20, 21 , L17 ]-VIP(1-23)/RP might be a promising agent for treatment of airway inflammatory diseases.

Strategic application of self-micellizing solid dispersion technology to respirable powder formulation of tranilast for improved therapeutic potential

PurposeThe present study aimed to develop an inhalable self-micellizing solid dispersion of tranilast (SMSD/TL) using poly[MPC-co-BMA] to improve the therapeutic potential and safety. MethodsThe safety of poly[MPC-co-BMA] in lungs was assessed using rat lung epithelium-derived L2 cells. SMSD/TL and respirable powder of SMSD/TL (SMSD/TL-RP) were prepared using a wet milling system and jet mill, respectively. The physicochemical properties of TL formulations were characterized in terms of dissolution, morphology, and particle size. Pharmacological and pharmacokinetic studies were also conducted on inhaled SMSD/TL-RP. ResultsThe lactate dehydrogenase level from L2 cells treated with poly[MPC-co-BMA] was lower than that with polysorbate 80, a positive control. SMSD/TL showed enhanced dissolution behavior of TL. The jet milled SMSD/TL particles easily separated from the lactose carrier, and the particle size was suitable for inhalation. Compared with RP of TL, inhaled SMSD/TL-RP (100μg-TL/rat) could more strongly suppress the inflammatory responses in antigen-sensitized rats. The TL level in plasma after intratracheal administration of SMSD/TL-RP at a pharmacological effective dose (100μg-TL/rat) was ca. 4.2-fold lower than that after oral administration of TL solution at a clinical dose (1.67mg/kg). ConclusionSMSD/TL-RP might be an attractive dosage form to improve the anti-inflammatory effects and safety of TL.

Chemical synthesis and formulation design of a PEGylated vasoactive intestinal peptide derivative with improved metabolic stability

The present study aimed to design a PEGylated VIP derivative, [Arg15, 20, 21, Leu17]-VIP-GRR (IK312532), with improved metabolic stability, and develop its respirable powder (RP) formulation for inhalation therapy. IK312532 was chemically conjugated with PEG (5kDa, P5K), the physicochemical and biochemical properties of which were characterized by CD spectral analysis, binding assays, and metabolic stability. CD spectral analysis demonstrated that PEG conjugation had no impact on the conformational structure of IK312532. Although the receptor-binding activity of IK312532/P5K (IC50: 82nM) was estimated to be ca. 30-fold less than that of IK312532 (IC50: 2.8nM), the metabolic stability of IK312532/P5K was highly improved. The IK312532/P5K was jet-milled and blended with lactose carrier particles to provide RP formulation of IK312532/P5K (IK312532/P5K-RP). In vitro inhalation performance and in vivo pharmacological effects of the IK312532/P5K-RP in antigen-sensitized rats were also evaluated. In cascade impactor analyses, fine particle fraction of IK312532/P5K-RP was calculated to be ca. 37%. Insufflation of IK312532/P5K-RP (150μg of IK312532/P5K) in antigen-sensitized rats resulted in marked attenuation of inflammatory events, as evidenced by significant decreases in inflammatory biomarkers and granulocyte recruitment in pulmonary tissue 24h after the antigen challenge. From these findings, PEGylation of a VIP derivative, as well as its strategic application to the RP formulation, may be a viable approach to improve its therapeutic potential for the treatment of airway inflammatory diseases.

Development of cyclosporine A-loaded dry-emulsion formulation using highly purified glycerol monooleate for safe inhalation therapy

The main objective of this study was to improve the safety and oxidative stability of glycerol monooleate (GMO)-based dry-emulsion (DE) formulation containing cyclosporine A (CsA) for inhalation therapy. GMO or highly purified GMO (hpGMO) was used as surfactant for the DE formulations (GMO/DE or hpGMO/DE), the toxicological and physicochemical properties of which were characterized with a focus on oxidative stability, in vitro/in vivo toxicity, and dissolution property. Incubation of GMO at oxidation accelerating conditions for 10 days at 60°C resulted in the formation of lipid peroxides as evidenced by increased malondialdehyde (111 μmol/mg); however, hpGMO samples exhibited increase of only 20.7 μmol/mg in malondialdehyde level. No significant acute cytotoxicity was observed in rat alveolar L2 cells exposed to hpGMO (0.28mM), and intratracheal administration of hpGMO powder in rats did not cause an increase of the plasma LDH level. The hpGMO/DE exhibited marked improvement in dissolution behavior of CsA, and stable fine micelles with a mean diameter of 320 nm were formed when suspended in water. A respirable powder formulation of hpGMO/DE (hpGMO/DE-RP) was newly prepared, and its in vitro inhalation property and in vivo efficacy were also evaluated. The hpGMO/DE-RP exhibited high dispersibility in laser diffraction analysis and significantly improved potency to attenuate recruitment of inflammatory cells into airway and thickening of airway wall in an animal model. Thus, the strategic use of hpGMO would improve oxidative stability and local toxicity compared with a GMO-based DE formulation, and its application to RP formulation could be a promising approach for effective inhalation therapy.

Inhalable Powder Formulation of Pirfenidone with Reduced Phototoxic Risk for Treatment of Pulmonary Fibrosis

Orally-taken pirfenidone (PFD), an idiopathic pulmonary fibrosis drug, often causes severe phototoxicity. Present study aimed to develop a respirable powder formulation for PFD (PFD-RP) to minimize phototoxic risk. Photochemical properties of PFD were examined using a reactive oxygen species (ROS) assay and photostability testing. PFD-RP was characterized with a focus on photostability, in vitro inhalation performance, and the efficacy in antigen-sensitized rats. Pharmacokinetic studies were conducted after oral and intratracheal administration of PFD formulations. Although PFD solution exhibited photodegradation under simulated sunlight (250 W/m²), both PFD powder and PFD-RP were photochemically stable. Laser diffraction and cascade impactor analyses on PFD-RP suggested its high dispersion and fine in vitro inhalation performance. Inhaled PFD-RP (300 μg-PFD/rat) could suppress antigen-evoked pulmonary inflammation in rats as evidenced by decreases in recruited inflammatory cells and neutrophilia-related biomarkers in the lung. Exposure of PFD to light-exposed tissues (skin and eye) after intratracheal administration of PFD-RP at a pharmacologically effective dose (300 μg-PFD/rat) was 90-130-fold less than that of the oral PFD dosage form at a phototoxic dose (160 mg/kg). PFD-RP might be an attractive alternative to the current oral PFD therapy with a better safety margin.

Inhalable dry-emulsion formulation of cyclosporine A with improved anti-inflammatory effects in experimental asthma/COPD-model rats

The main purpose of the present study was to develop a novel respirable powder (RP) formulation of cyclosporine A (CsA) using a spray-dried O/W-emulsion (DE) system. DE formulation of CsA (DE/CsA) was prepared by spray-drying a mixture of erythritol and liquid O/W emulsion containing CsA, polyvinylpyrrolidone, and glyceryl monooleate as emulsifying agent. The DE/CsA powders were mixed with lactose carriers to obtain an RP formulation of DE/CsA (DE/CsA-RP), and its physicochemical, pharmacological, and pharmacokinetic properties were evaluated. Spray-dried DE/CsA exhibited significant improvement in dissolution behavior with ca. 4500-fold increase of dissolution rate, and then, nanoemulsified particles were reconstituted with a mean diameter of 317 nm. Laser diffraction analysis on the DE/CsA-RP suggested high dispersion of DE/CsA on the surface of the lactose carrier. Anti-inflammatory properties of the inhaled DE/CsA-RP were characterized in antigen-sensitized asthma/COPD-model rats, in which the DE/CsA-RP was more potent than the RP formulation of physical mixture containing CsA and erythritol in inhibiting inflammatory responses, possibly due to the improved dissolution behavior. Pharmacokinetic studies demonstrated that systemic exposure of CsA after intratracheal administration of the DE/CsA-RP at a pharmacologically effective dose (100 μg-CsA/rat) was 50-fold less than that of the oral CsA dosage form at a toxic dose (10 mg/kg). From these findings, use of inhalable DE formulation of CsA might be a promising approach for the treatment of airway inflammatory diseases with improved pharmacodynamics and lower systemic exposure.

Formulation design and in vivo evaluation of dry powder inhalation system of new vasoactive intestinal peptide derivative ([R 15, 20, 21, L 17, A 24,25, des-N 28]-VIP-GRR) in experimental asthma/COPD model rats

Vasoactive intestinal peptide (VIP) has been considered as a promising drug candidate for asthma and COPD because of its potent immunomodulating and anti-inflammatory activities. Recently, our group developed a new VIP derivative, [R 15, 20, 21, L 17, A 24,25, des-N 28]-VIP-GRR (IK312548), with improved chemical and metabolic stability. In the present study, a dry powder inhaler system of IK312548 was designed for inhalation therapy with minimal systemic side effects, the physicochemical properties of which were also evaluated with a focus on morphology, particle size distribution, inhalation performance, and peptide stability. Laser diffraction and cascade impactor analysis suggested high dispersion and deposition in the respiratory organs with a fine particle fraction of 31.2%. According to UPLC/ESI-MS and circular dichroic spectral analyses, no significant changes in the purity and structure of VIP derivative were observed during preparation of respirable formulation. Anti-inflammatory properties of IK312548 respirable powder (RP) were characterized in antigen-sensitized asthma/COPD-model rats. There were marked inflammatory cells infiltrated into the lung tissues of experimental asthma/COPD-model rats; however, intratracheal administration of IK312548-RP led to significant reductions of recruited inflammatory cells in lung tissues and BALF by 72 and 78%, respectively. Thus, respirable powder formulation of IK312548 might be a promising medication for asthma, COPD, and other airway inflammatory diseases.

Inhalable Sustained-Release Formulation of Glucagon: In Vitro Amyloidogenic and Inhalation Properties, and In Vivo Absorption and Bioactivity

The present study aimed to develop novel glucagon-loaded PLGA nanospheres without cytotoxic fibril formation for chronic glucagon replacement therapy. Glucagon-loaded nanospheres (GLG/NS) were prepared by an emulsion solvent diffusion method in oil, and a respirable powder formulation (GLG/NS-RP) was prepared with a jet mill. Physicochemical and inhalation properties of GLG/NS-RP were characterized, and pharmacokinetic behavior and hyperglycemic effect of intratracheally instilled GLG/NS-RP were evaluated in rats. Although preparation of GLG/NS using glucagon solution at concentrations over 10 mg/mL led to significant formation of cytotoxic glucagon aggregates, glucagon solution at less than 5 mg/mL did not cause structural changes. Drug release behavior of GLG/NS showed a biphasic pattern with an initial burst and slow diffusion. Laser diffraction and cascade impactor analyses of GLG/NS-RP suggested high dispersion and deposition in the respiratory organs with a fine particle fraction of 20.5%. After the intratracheal administration of the GLG/NS-RP (200 μg glucagon/kg) in rats, glucagon was released in a sustained manner, leading to sustained hyperglycemic effects compared with those of normal glucagon powder. These data would suggest a therapeutic benefit of the newly developed GLG/NS-RP as an alternative to the injection form of glucagon currently used.

In vitro and in vivo characterization on amorphous solid dispersion of cyclosporine A for inhalation therapy

Cyclosporine A (CsA) has been clinically used as immunosuppressant, and new application for airway inflammation was also proposed. However, the clinical use of CsA was limited due to severe adverse effects after systemic exposure and the poor solubility. In the present investigation, novel respirable powder (RP) of CsA was developed for pulmonary administration with use of solid dispersion of wet-milled CsA (WM/CsA), and the physicochemical and pharmacological properties of the WM/CsA and its RP formulation were characterized. CsA in the solid dispersion was found to be amorphous by X-ray powder diffraction and differential scanning calorimetry. It exhibited the improved dissolution behavior as compared to active pharmaceutical ingredients. Laser diffraction and cascade impactor analysis of newly developed WM/CsA-RP, consisting of jet-milled WM/CsA and lactose carriers, suggested high dispersion and deposition in the respiratory organs with the emitted dose and the fine particle fraction of 96 and 54%, respectively. Intratracheal administration of WM/CsA-RP (100 µg CsA) in experimental inflammatory rats led to 71 and 85% reduction of granulocyte recruitment in bronchoalveolar lavage fluids and lung tissues, respectively, with showing ca 10 2-fold reduced AUC and C max values of plasma CsA as compared to the oral dosage form of CsA at toxic concentration (10 mg/kg). Upon these findings, WM/CsA-RP would be efficacious dosage form for clinical treatment of airway inflammations with minimal systemic side effects.