Clinical safety, tolerability, pharmacokinetics, and pharmacodynamics of the novel factor Xa inhibitor edoxaban in healthy volunteers.

This is a clinical safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) study of a single ascending dose (SAD) and a multiple ascending dose (MAD) of the oral direct factor Xa inhibitor edoxaban in healthy males. The placebo-controlled, single-blind, randomized, 2-part study consists of a SAD arm with 85 subjects (10, 30, 60, 90, 120, 150 mg) and a MAD arm with 36 subjects (90 mg daily, 60 mg twice daily, 120 mg daily). Effects of food and formulation (tablet vs solution) are assessed in a crossover substudy. In the SAD, doses are well tolerated up to 150 mg. Exposure is proportional to dose. PK profiles are consistent across dose with rapid absorption, biphasic elimination, and terminal elimination half-life of 5.8 to 10.7 hours. In the MAD, mean accumulation after daily dosing is 1.10 to 1.13 and consistent with elimination half-life of 8.75 to 10.4 hours. Intrasubject variability ranges from 12% to 17% for area under the curve. In general, plasma edoxaban concentrations are linearly correlated with coagulation parameters. Edoxaban is safe and well tolerated with no dose-dependent increases in adverse events. It is concluded that single and multiple doses of edoxaban are safe and well tolerated up to 150 mg with predictable PK and PD profiles.

Effect of the type of lubricant on the characteristics of orally disintegrating tablets manufactured using the phase transition of sugar alcohol.

The aim of this study was to evaluate the effect of lubricants on the characteristics of orally disintegrating (OD) tablets manufactured using the phase transition of sugar alcohol. OD tablets were produced by directly compressing a mixture containing lactose-xylitol granules, disintegrant, glidant and lubricant, and subsequent heating. The effect of the type of lubricant on the tablet characteristics was evaluated using magnesium stearate (Mg-St), sodium stearyl fumarate (SSF), and talc as lubricants. The hardness of the tablets increased to ca. 6kp as a result of heating, regardless of the kind of lubricant. The oral disintegration time of the tablets containing Mg-St or SSF increased with an increase in the hardness. In contrast, the oral disintegration time of the tablets containing talc was not changed despite of an increase in hardness. The water absorption rate of the tablets containing talc was much faster than that of the tablets containing other lubricants. The surface free energy measurement showed that the polarity of the tablet components containing talc was remarkably increased by heating. The water absorption rate of the tablets containing talc was also increased by heating. These results indicate that a more hydrophilic surface might be attained by heating the talc. Consequently, talc was demonstrated to be the most desirable lubricant for the preparation of OD tablets based on the principle of the phase transition of sugar alcohol.

Effect of preparation method on properties of orally disintegrating tablets made by phase transition.

In order to evaluate the effect of preparation method on the properties of orally disintegrating (OD) tablets, OD tablets were prepared by compressing a mixture of high melting point sugar alcohol (HMP-SA) and low melting point sugar alcohol (LMP-SA) and subsequent heating. In the direct compression method (DCM) where the LMP-SA was added as a powder, both hardness and disintegration time were increased by decreasing the particle size of the LMP-SA. In the wet granule compression method (WGCM), where the LMP-SA was added as an aqueous binder solution, the tablets became harder with less heating compared to tablets prepared by DCM. Using 1% xylitol as the LMP-SA provided tablets with sufficient hardness when prepared by WGCM, as opposed to DCM where 5% xylitol was necessary to prepare tablets with similar hardness. These results suggest that uniformly distributed LMP-SA on the surface of HMP-SA particles in WGCM might diffuse more easily during the heating process compared to mechanically mixed LMP-SA in DCM, resulting in an increase in tablet hardness even with a short heating time and low content of LMP-SA. In addition, disintegration and hardness stability of the tablets were affected by the LMP-SA content when prepared by WGCM, suggesting that the LMP-SA content should be regulated to assure the stability of OD tablet characteristics.

Evaluation of rapidly disintegrating tablets manufactured by phase transition of sugar alcohols.

The aim of the present study was to assess the properties of rapidly disintegrating (RD) tablets manufactured by the phase transition method. RD tablets were produced by compressing powder containing erythritol (melting point: 122 degrees C) and xylitol (melting point: 93 approximately 95 degrees C), and then heating at about 93 degrees C for 15 min. The hardness and oral disintegration time of the heated tablets increased with an increase of the xylitol content. These results suggested that the heating process and xylitol content might influence the properties of RD tablets. Then we evaluated the physicochemical properties of the RD tablets, including the median pore size, crystallinity, hardness, and oral disintegration time of tablets made with and without heating. After heating, the median pore size of the tablets was increased and tablet hardness was also increased. The increase of tablet hardness with heating and storage did not depend on the crystal state of the lower melting point sugar alcohol. It is concluded that a combination of low and high melting point sugar alcohols, as well as a phase transition in the manufacturing process, are important for making RD tablets without any special apparatus.

Investigation of water mobility and diffusivity in hydrating micronized low-substituted hydroxypropyl cellulose, hydroxypropylmethyl cellulose, and hydroxypropyl cellulose matrix tablets by magnetic resonance imaging (MRI).

The water mobility and diffusivity in the gel-layer of hydrating low-substituted hydroxypropyl cellulose (LH41) tablets with or without a drug were investigated by magnetic resonance imaging (MRI) and compared with those properties in the gel-layer of hydroxypropylmethyl cellulose (HPMC) and hydroxypropyl cellulose (HPC) tablets. For this purpose, a localized image-analysis method was newly developed, and the spin-spin relaxation time (T(2)) and apparent self-diffusion coefficient (ADC) of water in the gel-layer were visualized in one-dimensional maps. Those maps showed that the extent of gel-layer growth in the tablets was in the order of HPC>HPMC>>LH41, and there was a water mobility gradient across the gel-layers of all three tablet formulations. The T(2) and ADC in the outer parts of the gel-layers were close to those of free water. In contrast, these values in the inner parts of the gel-layer decreased progressively; suggesting that the water mobility and diffusivity around the core interface were highly restricted. Furthermore, the correlation between the T(2) of (1)H proton in the gel-layer of the tablets and the drug release rate from the tablets was observed.

Development of controlled release matrix pellets by annealing with micronized water-insoluble or enteric polymers.

The purpose of this study was to develop a new method for preparing controlled release (CR) matrix pellets by annealing with water-insoluble polymers, and to elucidate a relationship between the annealing temperature of the matrix pellets and a glass transition temperature (T(g)) or a minimum film-forming temperature (MFT) of the polymer/plasticizer systems that constituted the matrix pellets. The pellets containing theophylline as a model drug were prepared by the extrusion-spheronization method and subsequent annealing. The pellets were characterized mainly by pellet formation, release studies, and thermal evaluations. It was apparent that the annealing temperature for the CR matrix pellets was related to the T(g) and MFT of the polymer/plasticizer systems. For ethylcellulose (EC) containing 22.7% triethylcitrate (TEC), the annealing temperature required for preparing CR pellets was 80 degrees C, which was more than 20 degrees C higher than the T(g) and MFT of this EC/TEC system. In contrast, hydroxypropylmethylcellulose acetate succinate (HPMCAS) containing 22.7% TEC could be used to prepare CR pellets without heating. The T(g) of this HPMCAS/TEC system was about 60 degrees C and the MFT was lower than 20 degrees C, indicating that water can act as a plasticizer for HPMCAS and that HPMCAS/TEC pellets could be annealed at room temperature. These results suggest that MFT is a better indicator than T(g) for estimating annealing temperature. SEM observation showed that the EC/TEC pellets annealed at 80 degrees C had a matrix structure with coalesced particles. On the contrary, unannealed pellets consisted of individually distinguishable particles. The release rate of drug from the matrix CR pellets was dependent on the drug concentration and polymer to plasticizer ratio.