Naofumi Hashimoto

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 microg 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.

Dry powder inhalation systems for pulmonary delivery of therapeutic peptides and proteins

Background: Dry powder inhaler (DPI) systems are widely accepted as an alternative to injection and oral administration of therapeutic peptides and proteins. In contrast to oral therapy, pulmonary administration eliminates the potential for poor absorption and high metabolism in the gastrointestinal tract and it also evades first-pass effects in the liver. Inhalation therapy does not cause pain, unlike injection therapy, and this reduces the strain on the patient, possibly leading to improved treatment outcomes. Objective: Alongside the expansion of the DPI market, the science and engineering of dry powder formulations and devices have also grown. In this review, we present information regarding some recent advances in this expanding field, with emphasis on pulmonary delivery of therapeutic peptides and proteins. Methods: The scope of this review was defined by patent information on DPI devices, formulations and pulmonary delivery of therapeutic peptides and proteins for topical and systemic administration. Patent and bibliographic searches were carried out using various databases and websites, including CAplus, United States Patent and Trademark Office patent full-text and image database, Industrial Property Digital Library, Esp@cenet, World Intellectual Property Organization patentscope, Freepatentsonline, and PubMed database. Results/conclusion: A number of research efforts have demonstrated the feasibility of pulmonary delivery systems for therapeutic peptides and proteins, employing novel inhaler devices, powder engineering technologies, functional drug carriers and absorption enhancers. Optimized drug delivery would be achieved not only by improving relatively simple inhaler devices but also by more sophisticated formulations that disperse easily in the air stream.

Improved dissolution and pharmacokinetic behavior of cyclosporine A using high-energy amorphous solid dispersion approach

The aim of the present investigation is to develop solid dispersion (SD) formulations of cyclosporine A (CsA) for improving the oral bioavailability of CsA. Amorphous SDs of CsA with eight hydrophilic polymers were prepared with wet-mill employing zirconia beads. The physicochemical properties were characterized with a focus on morphology, crystallinity, thermal behavior, dissolution, and interaction of CsA with co-existing polymer. Although CsA molecules were found to be amorphous in all wet-milled formulations, some SD formulations failed to improve the dissolution. Of all CsA formulations, SD using polymer with HPC(SSL) exhibited the largest improvement in dissolution behavior. Pharmacokinetic profiling of orally dosed CsA in rats was carried out using UPLC/ESI-MS. After the oral administration of HPC(SSL)-based SD, enhanced CsA exposure was observed with increases in C(max) and AUC of ca. 5-fold, and the variation in AUC was ca. 40% less than that of amorphous CsA. Infrared spectroscopic studies suggested an interaction between CsA and HPC(SSL), as evidenced by the conformational transition of CsA. From the improved dissolution and pharmacokinetic data, the amorphous SD approach using wet-milling technology should lead to consistent and enhanced bioavailability, leading to an improved therapeutic potential of CsA.

Development of High-Energy Amorphous Solid Dispersion of Nanosized Nobiletin, a Citrus Polymethoxylated Flavone, with Improved Oral Bioavailability

Nobiletin (NOB), a citrus polymethoxylated flavone, attracts attention because of a wide range of pharmacological activities such as anti-inflammation, anticancer, and most notably ameliorative actions on memory impairment and β-amyloid pathology. However, clinical use of NOB could be partly limited due to its poor solubility and bioavailability, which might necessitate high doses in order to reach therapeutic plasma concentrations in the central nervous system (CNS) after oral administration. In the present study, amorphous solid dispersion (SD) of nanosized NOB (NOB/SD) was prepared by wet-milling technique with the aim of improving dissolution behavior and pharmacokinetic properties of NOB. Physicochemical properties of the NOB/SD were characterized with focus on surface morphology, particle size distribution, dissolution, and crystallinity assessment. Wet-milled NOB particles in NOB/SD appeared to be amorphous with a diameter of approximately 270 nm, and there was marked improvement in the dissolution behavior compared with that of crystalline NOB. After oral administration of NOB/SD, higher exposure of NOB was observed with increases of bioavailability and CNS distribution by 13- and sevenfold, respectively, compared with those of crystalline NOB. These findings suggest that an amorphous, nanosized SD could be a viable option for enhancing the bioavailability and CNS delivery of NOB.

Development of novel solid dispersion of tranilast using amphiphilic block copolymer for improved oral bioavailability

The present study aimed to develop novel solid dispersion (SD) of tranilast (TL) using amphiphilic block copolymer, poly[MPC-co-BMA] (pMB), to improve the dissolution and pharmacokinetic behavior of TL. pMB-based SD of TL (pMB-SD/TL) with drug loading of 50% (w/w) was prepared by wet-mill technology, and the physicochemical properties were characterized in terms of morphology, crystallinity, dissolution, and hygroscopicity. Powder X-ray diffraction and polarized light microscopic experiments demonstrated high crystallinity of TL in pMB-SD/TL. The pMB-SD/TL exhibited immediate micellization when introduced to aqueous media, forming fine droplets with a mean diameter of ca. 122 nm. There was marked improvement in the dissolution behavior for the pMB-SD/TL even under acidic conditions, although the supersaturated TL concentration gradually decreased. NMR analyses demonstrated interaction between TL and pMB, as evidenced by the chemical shift drifting and line broadening. Pharmacokinetic behaviors of orally dosed TL formulations were evaluated in rats using UPLC/ESI-MS. After oral administration of pMB-SD/TL (10mg TL/kg) in rats, enhanced TL exposure was observed with increases of Cmax and AUC by 125- and 52-fold, respectively, compared with those of crystalline TL. From these findings, pMB-based SD formulation approach might be an efficacious approach for enhancing the therapeutic potential of TL.

Development of anti-influenza virus drugs I : Improvement of oral absorption and in vivo anti-influenza activity of Stachyflin and its derivatives

AbstractPurpose. Stachyflin and its derivatives which are active against the influenza virus in vitro, were studied to improve their reduced in vivo activity after oral administration by chemical modification and some vehicles. Methods. The solubility was examined for different vehicles. The improvement of gastrointestinal absorption was evaluated by the plasma concentration after oral administration to mice or the in situ loop method with rats. The in vivo anti-influenza activity was examined using mice infected with the influenza virus and evaluated based on the virus titer in the lung by TCID50. Results. PEG 400 showed the highest solubility of Stachyflin and its derivative among the vehicles studied. While no viral inhibition was found in the lung after oral administration of 0.5% HPMC suspension of Stachyflin, in vivo anti-influenza virus activity was found with the PEG 400 solution. The absorption of Stachyflin by PEG 400 showed about a fifty-fold increase in AUC compared with that of 0.5% HPMC suspension. Improving the oral absorption of Stachyflin led to an increase in the in vivo anti-influenza virus activity. When the Stachyflin derivative in PEG 4000 was administered orally, there was more enhancement of the oral absorption than with PEG 400. When the aqueous solution of the phosphate ester prodrugs of Stachyflin and its derivative was administered orally, the absorption of the parent compound was improved and in vivo anti-influenza virus activity was found. Conclusions. When Stachyflin and its derivatives were administered orally to mice with a solution in PEG and an aqueous solution of their phosphate ester, their oral absorption was improved and in vivo anti-influenza virus activity was observed.

Development of nanocrystal formulation of meloxicam with improved dissolution and pharmacokinetic behaviors.

The present study aimed to develop nanocrystal formulations of meloxicam (MEL) in order to enhance its biopharmaceutical properties and provide a rapid onset of action. Nanocrystal formulations were prepared by wet-milling and lyophilization with hydrophilic polymers used as aggregation inhibitors. Aggregation inhibitors were selected based on high-throughput screening of crystal growth inhibition in supersaturated MEL solution. Supersaturation of MEL was observed in PVP K-30, HPC-SSL, and POVACOAT Type F solution. Although the particle size distributions of pulverized MEL with PVP K-30 (MEL/PVP), HPC-SSL (MEL/HPC), and POVACOAT Type F (MEL/POVA) were in the nanometer range following lyophilization, increases in micron-sized aggregates were observed after storage at 60°C for 21 days. The order of increased amount of aggregates was MEL/POVA≫MEL/HPC>MEL/PVP. These findings showed that hydrophilic polymers that inhibited crystal growth in supersaturated MEL solutions tended to prevent aggregation. The dissolution behavior of all nanocrystal formulations tested was markedly enhanced compared with that of unpulverized MEL. Oral administration of MEL/PVP showed a 2.0h shortened Tmax and a 5.0-fold increase in bioavailability compared with unpulverized MEL. These findings showed that the MEL/PVP mixture was physicochemically stable and provided a rapid onset of action and enhanced bioavailability after oral administration.

Self-micellizing solid dispersion of cyclosporine A with improved dissolution and oral bioavailability.

The present study aimed to develop a self-micellizing solid dispersion (SMSD) of cyclosporine A (CsA) using an amphiphilic block copolymer, poly[MPC-co-BMA], to improve the biopharmaceutical properties of CsA. The cytotoxicity of poly[MPC-co-BMA] was assessed in rat intestinal IEC-6 cells, and the pMB was less cytotoxic than polysorbate 80, a non-ionic surfactant with a wide safety margin. SMSD/CsA was prepared using a wet-milling system, and its physicochemical properties were characterized in terms of morphology, crystallinity, dissolution, particle size distribution, and stability. The SMSD/CsA exhibited immediate formation of fine micelles with a mean diameter of ca. 180 nm when introduced into aqueous media. There was marked improvement in the dissolution behavior of the SMSD/CsA compared with amorphous CsA. Even after storage at 40°C/75% relative humidity, the dissolution behavior of aged SMSD/CsA seemed to be almost identical to that of its freshly prepared equivalent, and CsA in aged SMSD/CsA was still in amorphous form. After oral administration of SMSD/CsA (10 mg CsA/kg) in rats, enhanced CsA exposure was observed with increases of Cmax and BA by ca. 11- and 42-fold, respectively, compared with those of amorphous CsA. The poly[MPC-co-BMA]-based SMSD formulation system might be an efficacious dosage option for CsA to achieve improvements in oral bioavailability.

Renin Inhibitor: Transport Mechanism in Rat Small Intestinal Brush-Border Membrane Vesicles

The transport characteristics of the renin inhibitor ((3S,4S)-4-[N-morpholinoacetyl-(l-naphthyl)-L-alanyl-N-methyl-(4-thiazolyl)-L-alanyl]amino-3-hydroxy-5-cyclohexyl-l-(4-pyridyl)-l-pentanone; CH3-18) in rat small intestinal brush-border membrane vesicles (BBMV) were examined by a rapid filtration technique. The uptake of CH3-18 was markedly stimulated by an inwardly directed H+ gradient (pH 7.5 inside, pH 5.5 outside) and showed an uphill transport. It was competitively inhibited by tripeptides and tetrapeptides, but not by amino acids or dipeptides. A countertransport effect on the uptake of CH3-18 was observed in the vesicle preloaded with a tripeptide. Effects of the fragments of several renin inhibitors were evaluated by their inhibitory and countertransport effects on the uptake of CH3-18. The morpholino group at the N-terminal was found to be important for the uptake of CH3-18.

Biopharmaceutical characterization of nanocrystalline solid dispersion of coenzyme Q10 prepared with cold wet-milling system.

The present study aimed to develop a nano-crystalline solid dispersion (CSD) of coenzyme Q10 (CoQ10) using a newly developed cold wet-milling (CWM) system to enhance the dissolution and biopharmaceutical properties of CoQ10. CSD formulations of CoQ10 were prepared by the CWM system, and their physicochemical properties were characterized in terms of morphology, crystallinity, particle size distribution, dissolution, and photostability. Application of the CWM system to CoQ10 led to successful development of a CSD formulation (CoQ10/CWM) with a mean CoQ10 diameter of ca. 129 nm, although a conventional wet-milling system failed due to evident formation of large particles. In comparison with crystalline CoQ10, marked improvement in the aqueous dissolution was seen for the CoQ10/CWM, with no significant decrease of photostability. Oral bioavailability and hepatoprotective effects of orally dosed CoQ10 samples were also evaluated in rats. After oral administration of CoQ10/CWM (100 mg CoQ10/kg) in rats, there appeared to be a similar Tmax value and 13-fold increase of bioavailability compared with crystalline CoQ10. In a rat model of acute liver injury, pretreatment with CoQ10/CWM (100 mg CoQ10/kg, twice) led to marked attenuation of hepatic damage as evidenced by decreased ALT and AST, surrogate biomarkers for hepatic injury, whereas crystalline CoQ10 was less effective. The CSD approach with the new CWM system might be a promising dosage option for improving the nutraceutical values of CoQ10.