PLEKHG4B enables actin cytoskeletal remodeling during epithelial cell-cell junction formation.

Cell-cell junction formation requires actin cytoskeletal remodeling. Here, we show that PLEKHG4B, a Rho-guanine nucleotide exchange factor (Rho-GEF), plays a crucial role in epithelial cell-cell junction formation. Knockdown of PLEKHG4B decreased Cdc42 activity and tended to increase RhoA activity in A549 cells. A549 monolayer cells showed 'closed junctions' with closely packed actin bundles along the cell-cell contacts, but PLEKHG4B knockdown suppressed closed junction formation, and PLEKHG4B-knockdown cells exhibited 'open junctions' with split actin bundles located away from the cell-cell boundary. In Ca2+-switch assays, PLEKHG4B knockdown delayed the conversion of open junctions to closed junctions and ß-catenin accumulation at cell-cell junctions. Furthermore, PLEKHG4B knockdown abrogated the reduction in myosin activity normally seen in the later stage of junction formation. The aberrant myosin activation and impairments in closed junction formation in PLEKHG4B-knockdown cells were reverted by ROCK inhibition or LARG/PDZ-RhoGEF knockdown. These results suggest that PLEKHG4B enables actin remodeling during epithelial cell-cell junction maturation, probably by reducing myosin activity in the later stage of junction formation, through suppressing LARG/PDZ-RhoGEF and RhoA-ROCK pathway activities. We also showed that annexin A2 participates in PLEKHG4B localization to cell-cell junctions.This article has an associated First Person interview with the first author of the paper.

Phosphorylation and dephosphorylation of Ser852 and Ser889 control the clustering, localization and function of PAR3.

Cell polarity is essential for various asymmetric cellular events, and the partitioning defective (PAR) protein PAR3 (encoded by PARD3 in mammals) plays a unique role as a cellular landmark to establish polarity. In epithelial cells, PAR3 localizes at the subapical border, such as the tight junction in vertebrates, and functions as an apical determinant. Although we know a great deal about the regulators of PAR3 localization, how PAR3 is concentrated and localized to a specific membrane domain remains an important question to be clarified. In this study, we demonstrate that ASPP2 (also known as TP53BP2), which controls PAR3 localization, links PAR3 and protein phosphatase 1 (PP1). The ASPP2-PP1 complex dephosphorylates a novel phosphorylation site, Ser852, of PAR3. Furthermore, Ser852- or Ser889-unphosphorylatable PAR3 mutants form protein clusters, and ectopically localize to the lateral membrane. Concomitance of clustering and ectopic localization suggests that PAR3 localization is a consequence of local clustering. We also demonstrate that unphosphorylatable forms of PAR3 exhibited a low molecular turnover and failed to coordinate rapid reconstruction of the tight junction, supporting that both the phosphorylated and dephosphorylated states are essential for the functional integrity of PAR3.

MTCL1 plays an essential role in maintaining Purkinje neuron axon initial segment.

The axon initial segment (AIS) is a specialized domain essential for neuronal function, the formation of which begins with localization of an ankyrin-G (AnkG) scaffold. However, the mechanism directing and maintaining AnkG localization is largely unknown. In this study, we demonstrate that in vivo knockdown of microtubule cross-linking factor 1 (MTCL1) in cerebellar Purkinje cells causes loss of axonal polarity coupled with AnkG mislocalization. MTCL1 lacking MT-stabilizing activity failed to restore these defects, and stable MT bundles spanning the AIS were disorganized in knockdown cells. Interestingly, during early postnatal development, colocalization of MTCL1 with these stable MT bundles was observed prominently in the axon hillock and proximal axon. These results indicate that MTCL1-mediated formation of stable MT bundles is crucial for maintenance of AnkG localization. We also demonstrate that Mtcl1 gene disruption results in abnormal motor coordination with Purkinje cell degeneration, and provide evidence suggesting possible involvement of MTCL1 dysfunction in the pathogenesis of spinocerebellar ataxia.

Use of Mixer Torque Rheometer to Clarify the Relationship between the Kneading States of Wet Mass and the Dissolution of Final Product in High Shear Granulation.

The properties of wet mass, which indicate the progress of high shear granulation processes, usually have an effect on final product properties, such as tablet dissolution. The mixer torque rheometer (MTR) is a useful tool for quantitatively measuring the 'kneading state' of wet mass and detecting differences in granules. However, there have been no studies of the relationship between the MTR torque and the final product properties to date. In this study, we measured the MTR torque of wet granules at different kneading states, which were prepared by changing the granulation conditions. We then evaluated the relationship between the MTR torque and the dissolution rate of the final product properties. The amperage of the high shear granulator is usually monitored during granulation, but we could not detect a difference in the kneading state through the amperage. However, using MTR torque we were able to quantify the difference of the wet mass. Moreover, MTR torque showed a high correlation with dissolution, compared with the correlations with other intermediate properties, such as granules particle size and tablet hardness. These other properties are affected by following processes and are not properties that directly relate to the kneading state. Thus, MTR torque is a property of wet mass after granulation, and it can be used to directly evaluate differences of the kneading state, and as a result, dissolution. These results indicate the importance of controlling the kneading state, i.e., the progress of granulation, and the utility of MTR for detecting differences in wet mass.

A Scale-up Approach for Film Coating Process Based on Surface Roughness as the Critical Quality Attribute.

Scale-up approaches for film coating process have been established for each type of film coating equipment from thermodynamic and mechanical analyses for several decades. The objective of the present study was to establish a versatile scale-up approach for film coating process applicable to commercial production that is based on critical quality attribute (CQA) using the Quality by Design (QbD) approach and is independent of the equipment used. Experiments on a pilot scale using the Design of Experiment (DoE) approach were performed to find a suitable CQA from surface roughness, contact angle, color difference, and coating film properties by terahertz spectroscopy. Surface roughness was determined to be a suitable CQA from a quantitative appearance evaluation. When surface roughness was fixed as the CQA, the water content of the film-coated tablets was determined to be the critical material attribute (CMA), a parameter that does not depend on scale or equipment. Finally, to verify the scale-up approach determined from the pilot scale, experiments on a commercial scale were performed. The good correlation between the surface roughness (CQA) and the water content (CMA) identified at the pilot scale was also retained at the commercial scale, indicating that our proposed method should be useful as a scale-up approach for film coating process.

Nicotine enhances the malignant potential of human pancreatic cancer cells via activation of atypical protein kinase C.

BACKGROUND: Pancreatic cancer (PC) is the most lethal malignancy among solid tumors, and the most common risk factor for its development is cigarette smoking. Atypical protein kinase C (aPKC) isozymes function in cell polarity, proliferation, and survival, and have also been implicated in carcinogenesis. However, the involvement of aPKC in PC progression and the effect of nicotine, a major component of cigarette smoke, on the biological activities of aPKC remain to be fully elucidated. METHODS: We investigated the effects of nicotine on the proliferation, migration and invasion of the human PC cell lines Panc1 and BxPC3. We analyzed aPKC localization and activity by immunohistochemistry and in vitro kinase assays, respectively, to assess their involvement in the regulation of PC progression. Moreover, we examined the effect of nicotine on implanted peritoneal tumors of PC cells in mice. RESULTS: Nicotine enhanced cell proliferation, migration and invasion in Panc1 and BxPC3 cells. In nicotine-treated PC cells, the aPKC was significantly activated. We also found that nicotine induced phosphatidylinositol 3-kinase (PI3K) signal activation, and a specific inhibitor of the nicotine acetylcholine receptor (nAChR) as well as knockdown of nAChR prevented nicotine-mediated Akt phosphorylation and aPKC activation. In a peritoneal dissemination model of PC, nicotine-treated mice had larger tumors and increased numbers of nodules. Immunohistochemistry showed enhanced expression levels of aPKC and phosphorylated Akt in nodules from nicotine-treated mice. CONCLUSIONS AND GENERAL SIGNIFICANCE: Nicotine induces aberrant activation of aPKC via nAChR/PI3K signaling in PC cells, resulting in enhancement of cellular proliferation, migration and invasion.

Application of Terahertz Attenuated Total Reflection Spectroscopy to Detect Changes in the Physical Properties of Lactose during the Lubrication Process Required for Drug Formulation.

Manufacturing the solid dosage form of an orally administered drug requires lubrication to enhance manufacturability, ensuring that critical quality attributes such as disintegration and dissolution of the drug product are maintained during manufacture. Here, to evaluate lubrication performance during manufacture, we used terahertz attenuated total reflection (THz-ATR) spectroscopy to detect differences in the physical characteristics of the lubricated powder. We applied a simple formulation prepared by blending granulated lactose as filler with magnesium stearate as lubricant. A flat tablet was prepared using the lubricated powder to acquire sharp THz-ATR absorption peaks of the samples. First, we investigated the effects of lubricant concentration and compression pressure on preparation of the tablet and then determined the effect of the pressure applied to samples in contact with the ATR prism on sample absorption amplitude. We focused on the differences in the magnitudes of spectra at the lactose-specific frequency. Second, we conducted the dynamic lubrication process using a 120-L mixer to investigate differences in the magnitudes of absorption corresponding to the lactose-specific frequency during lubrication. In both studies, enriching the lubricated powder with a higher concentration of magnesium stearate or prolonging blending time correlated with higher magnitudes of spectra at the lactose-specific frequency. Further, in the dynamic lubrication study, the wettability and disintegration time of the tablets were compared with the absorption spectra amplitudes at the lactose-specific frequency. We conclude that THz-ATR spectroscopy is useful for detecting differences in densities caused by a change in the physical properties of lactose during lubrication.

Effect of the External Lubrication Method for a Rotary Tablet Press on the Adhesion of the Film Coating Layer.

External lubrication is a useful method which reduces the adhesion of powder to punches and dies by spraying lubricants during the tableting process. However, no information is available on whether the tablets prepared using an external lubrication system can be applicable for a film coating process. In this study, we evaluated the adhesion force of the film coating layer to the surface of tablets prepared using an external lubrication method, compared with those prepared using internal lubrication method. We also evaluated wettability, roughness and lubricant distribution state on the tablet surface before film coating, and investigated the relationship between peeling of the film coating layer and these tablet surface properties. Increasing lubrication through the external lubrication method decreased wettability of the tablet surface. However, no change was observed in the adhesion force of the film coating layer. On the other hand, increasing lubrication through the internal lubrication method, decreased both wettability of the tablet surface and the adhesion force of the film coating layer. The magnesium stearate distribution state on the tablet surface was assessed using an X-ray fluorescent analyzer and lubricant agglomerates were observed in the case of the internal lubrication method. However, the lubricant was uniformly dispersed in the external lubrication samples. These results indicate that the distribution state of the lubricant affects the adhesion force of the film coating layer, and external lubrication maintained sufficient lubricity and adhesion force of the film coating layer with a small amount of lubricant.

Quantitative Appearance Inspection for Film Coated Tablets.

The decision criteria for the physical appearance of pharmaceutical products are subjective and qualitative means of evaluation that are based entirely on human interpretation. In this study, we have developed a comprehensive method for the quantitative analysis of the physical appearance of film coated tablets. Three different kinds of film coated tablets with considerable differences in their physical appearances were manufactured as models, and their surface roughness, contact angle, color measurements and physicochemical properties were investigated as potential characteristics for the quantitative analysis of their physical appearance. All of these characteristics were useful for the quantitative evaluation of the physical appearances of the tablets, and could potentially be used to establish decision criteria to assess the quality of tablets. In particular, the analysis of the surface roughness and film coating properties of the tablets by terahertz spectroscopy allowed for an effective evaluation of the tablets' properties. These results indicated the possibility of inspecting the appearance of tablets during the film coating process.

The novel PAR-1-binding protein MTCL1 has crucial roles in organizing microtubules in polarizing epithelial cells.

The establishment of epithelial polarity is tightly linked to the dramatic reorganization of microtubules (MTs) from a radial array to a vertical alignment of non-centrosomal MT bundles along the lateral membrane, and a meshwork under the apical and basal membranes. However, little is known about the underlying molecular mechanism of this polarity-dependent MT remodeling. The evolutionarily conserved cell polarity-regulating kinase PAR-1 (known as MARK in mammals), whose activity is essential for maintaining the dynamic state of MTs, has indispensable roles in promoting this process. Here, we identify a novel PAR-1-binding protein, which we call microtubule crosslinking factor 1 (MTCL1), that crosslinks MTs through its N-terminal MT-binding region and subsequent coiled-coil motifs. MTCL1 colocalized with the apicobasal MT bundles in epithelial cells, and its knockdown impaired the development of these MT bundles and the epithelial-cell-specific columnar shape. Rescue experiments revealed that the N-terminal MT-binding region was indispensable for restoring these defects of the knockdown cells. MT regrowth assays indicated that MTCL1 was not required for the initial radial growth of MTs from the apical centrosome but was essential for the accumulation of non-centrosomal MTs to the sublateral regions. Interestingly, MTCL1 recruited a subpopulation of PAR-1b (known as MARK2 in mammals) to the apicobasal MT bundles, and its interaction with PAR-1b was required for MTCL1-dependent development of the apicobasal MT bundles. These results suggest that MTCL1 mediates the epithelial-cell-specific reorganization of non-centrosomal MTs through its MT-crosslinking activity, and cooperates with PAR-1b to maintain the correct temporal balance between dynamic and stable MTs within the apicobasal MT bundles.

Influence of binder droplet dimension on granulation rate during fluidized bed granulation.

Here, we statistically identified the critical factor of the granulation rate during the fluidized bed granulation process. Lactose was selected as the excipient and was granulated with several binders, including hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and polyvinylpyrrolidone. The viscosity, density, and surface tension of the binder solution, contact angle, and the work done during adhesion and cohesion between the binder and lactose, mist diameter, Stokes number, and the dimension of the droplet were considered. The Stokes number was defined as the ratio of the inertial force to the viscous-damping force of a particle. We confirmed that droplet diameter after adhesion had the highest correlation coefficient with the granulation rate constant in our investigated parameters. Partial least squares regression revealed two critical principal components of the granulation rate: one relating to the droplet dimension, which is composed of mist diameter and diameter and thickness of the droplet after adhesion of the binder to the lactose surface; and the other relating to wettability, which involves the work done during adhesion and cohesion, surface tension, and the thickness of the droplet after adhesion of the binder to the lactose surface.

A novel approach to establishing the design space for the oral formulation manufacturing process.

A novel approach to establishing the design space for the oral formulation manufacturing process was investigated. A response surface method incorporating multivariate spline interpolation was applied to overcome the nonlinear problem, which is always problematic in pharmaceutical development studies, and a bootstrap resampling technique, polynomial approximation technique, and 95% confidence intervals based on a nonparametric approach were applied to estimate the reliability of the established design space derived from the nonlinear response surface model. The critical quality attributes (CQAs) of intermediate material rather than the critical process parameters (CPPs) were chosen as the causal factors for the response variables, which were CQAs of the final product to avoid scale-gap and equipment-gap. This enabled the effective use of data sets accumulated during all pharmaceutical development studies. It was confirmed that a conservative border as well as an optimistic border of the design space for practical use was obtained considering the variability of the border of the design spaces on nonlinear response surfaces. Furthermore, the nonlinear response surface model using CQAs of intermediate material derived from data sets of a laboratory scale study and pilot scale studies could predict the CQA of the final product (2.5 h dissolution of commercial-scale study) with high accuracy. Consequently, the proposed novel approach overcame all of the difficulties for the manufacturing process development of oral formulations and this is the first study to demonstrate the effectiveness of the design space using CQA of intermediate material for the oral formulation manufacturing process.

High Glucose-stimulated aPKC Activation Promotes Pancreatic Cancer Cell Progression Through YAP Signaling.

BACKGROUND/AIM: Persistent hyperglycemia caused by diabetes mellitus is a risk factor for pancreatic cancer (PC). We have previously reported that aberrant activation of atypical protein kinase C (aPKC) enhances PC cell progression. However, no reports have elucidated whether hyperglycemia promotes PC cell progression and whether aPKC activation is related to PC cell progression mechanisms. MATERIALS AND METHODS: We examined whether high-glucose stimulation accelerates PC cell proliferation, migration, and invasion. Furthermore, to determine whether PC cells activate aPKC upon high-glucose stimulation, we measured the phosphorylation of aPKC at T560 in PC cells. RESULTS: High-glucose stimulation accelerated PC cell proliferation, migration, and invasion. High-glucose treatment increased aPKC's activated form, with T560 phosphorylation, in PC cells. However, aPKC knockdown attenuated these effects. aPKC reportedly induces cell transformation through Yes-associated protein (YAP) activation. YAP expression was increased in high glucose-treated PC cells but not in aPKC-knockdown cells. aPKC interacts with partitioning defective 3 (Par-3), which aids in establishing cell polarity and inhibits aPKC by binding as a substrate. In Par-3-knockdown PC cells, YAP expression increased independently of high-glucose treatment. Over-expression of Par-3 and aPKC-dominant negative mutants prevented the high glucose-stimulated nuclear localization of YAP. YAP forms a complex with the zinc finger E-box binding homeobox 1 protein (ZEB1), an activator of epithelial-mesenchymal transition. ZEB1 expression was increased by high glucose treatment or Par-3 knockdown, but aPKC knockdown suppressed this increase. CONCLUSION: High glucose-induced aPKC activation promotes PC progression by enhancing the YAP signaling pathway.

Evaluation of models for predicting spray mist diameter for scaling-up of the fluidized bed granulation process.

We evaluated models for predicting spray mist diameter suitable for scaling-up the fluidized bed granulation process. By precise selection of experimental conditions, we were able to identify a suitable prediction model that considers changes in binder solution, nozzle dimension, and spray conditions. We used hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose (HPMC), or polyvinylpyrrolidone (PVP) binder solutions, which are commonly employed by the pharmaceutical industry. Nozzle dimension and spray conditions for oral dosing were carefully selected to reflect manufacturing and small (1/10) scale process conditions. We were able to demonstrate that the prediction model proposed by Mulhem optimally estimated spray mist diameter when each coefficient was modified. Moreover, we developed a simple scale-up rule to produce the same spray mist diameter at different process scales. We confirmed that the Rosin-Rammler distribution could be applied to this process, and that its distribution coefficient was 1.43-1.72 regardless of binder solution, spray condition, or nozzle dimension.

The 8th and 9th tandem spectrin-like repeats of utrophin cooperatively form a functional unit to interact with polarity-regulating kinase PAR-1b.

Utrophin is a widely expressed paralogue of dystrophin, the protein responsible for Duchenne muscular dystrophy. Utrophin is a large spectrin-like protein whose C-terminal domain mediates anchorage to a laminin receptor, dystroglycan (DG). The rod domain, composed of 22 spectrin-like repeats, connects the N-terminal actin-binding domain and the C-terminal DG binding domain, and thus mediates molecular linkage between intracellular F-actin and extracellular basement membrane. Previously, we demonstrated that a cell polarity-regulating kinase, PAR-1b, interacts with the utrophin-DG complex, and positively regulates the interaction between utrophin and DG. In this study, we demonstrate that the 8th and 9th spectrin-like repeats (R8 and R9) of utrophin cooperatively form a PAR-1b-interacting domain, and that Ser1258 within R9 is specifically phosphorylated by PAR-1b. Substitution of Ser1258 to alanine reduces the interaction between utrophin and DG, suggesting that the Ser1258 phosphorylation contributes to the stabilization of the utrophin-DG complex. Interestingly, PAR-1b also binds and phosphorylates R8-9 of dystrophin, and colocalizes with dystrophin at the skeletal muscle membrane. These results reveal a novel function of the rod domain of utrophin beyond that of a passive structural linker connecting the N- and C-terminal domain.

Intracellular polarity protein PAR-1 regulates extracellular laminin assembly by regulating the dystroglycan complex.

Cell polarity depends on extrinsic spatial cues and intrinsic polarity proteins including PAR-aPKC proteins. In mammalian epithelial cells, cell-cell contacts provide spatial cues that activate the aPKC-PAR-3-PAR-6 complex to establish the landmark of the initial cellular asymmetry. PAR-1, a downstream target of the aPKC-PAR-3-PAR-6 complex, mediates further development of the apical and basolateral membrane domains. However, the relationships between the PAR-aPKC proteins and other extrinsic spatial cues provided by the extracellular matrix (ECM) remain unclear. Here, we show that PAR-1 colocalizes with laminin receptors and is required for the assembly of extracellular laminin on the basal surface of epithelial cells. Furthermore, PAR-1 regulates the basolateral localization of the dystroglycan (DG) complex, one of the laminin receptors essential for basement membrane formation. We also show that PAR-1 interacts with the DG complex and is required for the formation of a functional DG complex. These results reveal the presence of a novel inside-out pathway in which an intracellular polarity protein regulates the ECM organization required for epithelial cell polarity and tissue morphogenesis.

The Rho-guanine nucleotide exchange factor Solo decelerates collective cell migration by modulating the Rho-ROCK pathway and keratin networks.

Collective cell migration plays crucial roles in tissue remodeling, wound healing, and cancer cell invasion. However, its underlying mechanism remains unknown. Previously, we showed that the RhoA-targeting guanine nucleotide exchange factor Solo (ARHGEF40) is required for tensile force-induced RhoA activation and proper organization of keratin-8/keratin-18 (K8/K18) networks. Here, we demonstrate that Solo knockdown significantly increases the rate at which Madin-Darby canine kidney cells collectively migrate on collagen gels. However, it has no apparent effect on the migratory speed of solitary cultured cells. Therefore, Solo decelerates collective cell migration. Moreover, Solo localized to the anteroposterior regions of cell-cell contact sites in collectively migrating cells and was required for the local accumulation of K8/K18 filaments in the forward areas of the cells. Partial Rho-associated protein kinase (ROCK) inhibition or K18 or plakoglobin knockdown also increased collective cell migration velocity. These results suggest that Solo acts as a brake for collective cell migration by generating pullback force at cell-cell contact sites via the RhoA-ROCK pathway. It may also promote the formation of desmosomal cell-cell junctions related to K8/K18 filaments and plakoglobin.

The Epithelial Circumferential Actin Belt Regulates YAP/TAZ through Nucleocytoplasmic Shuttling of Merlin.

Circumferential actin belts underlying the adherens junctions of columnar epithelial cell monolayers control intercellular surface tension and cell shape to maintain tissue integrity. Yes-associated protein (YAP) and its paralog TAZ are proliferation-activating transcriptional coactivators that shuttle between the nucleus and cytoplasm. Previous studies suggest the importance of stress fibers in the actin cytoskeleton for regulation of YAP nuclear localization; however, the role of the circumferential actin belt on YAP localization remains unclarified. By manipulating actin tension, we demonstrate that circumferential actin belt tension suppresses YAP/TAZ nuclear localization. This suppression requires Merlin, an F-actin binding protein associated with adherens junctions. Merlin physically interacts with YAP/TAZ, and nuclear export sequences of Merlin are required for suppression. Together, with the observation that the association between E-cadherin and Merlin was diminished by tension in circumferential actin belts, our results suggest that released Merlin undergoes nucleocytoplasmic shutting and mediates export of YAP/TAZ from the nucleus.

Development of extended-release solid dispersion granules of tacrolimus: evaluation of release mechanism and human oral bioavailability.

OBJECTIVES: We aimed to prepare a once-daily modified-release oral formulation of tacrolimus by utilizing an extended-release granules (ERG). METHODS: Extended-release granules were prepared using ethylcellulose (EC), hydroxypropylmethylcellulose (HPMC) and lactose via a solvent evaporation method with ethanol. Physicochemical and biopharmaceutical studies were performed to determine the formulation with optimum release profile of tacrolimus from ERG. KEY FINDINGS: Tacrolimus existed in an amorphous state in ERG. Tacrolimus release from ERG was attenuated by EC and facilitated by lactose, suggesting that drug release kinetics could adequately be regulated by these components. Those release profiles were consistent with Higuchi's equation, suggesting a diffusion-type release mechanism. Smooth surface of ERG changed to the structure with pores after the release test, likely derived from the dissolution of HPMC and lactose. But ERG structure formed by EC was still maintained after the release test, leading to the longer maintenance of diffusion-type release. Two ERG formulations selected by blood concentration simulation successfully provided long-term retention of tacrolimus in blood in a human absorption study. CONCLUSIONS: We successfully developed the formulation exhibiting a significant reduction in Cmax , the longer mean residence time and AUC close to that of an immediate-release tacrolimus formulation, being preferred from the viewpoint of safe and effective immunosuppressant pharmacotherapy.

Preparation of extended release solid dispersion formulations of tacrolimus using ethylcellulose and hydroxypropylmethylcellulose by solvent evaporation method.

OBJECTIVES: Tacrolimus is a poorly water-soluble compound that is used to prevent allograft rejection. We aimed to prepare an extended release formulation of tacrolimus to achieve both an extended release profile and improved solubility of tacrolimus. METHODS: Extended release granules (ERG) of tacrolimus were prepared with lactose, ethylcellulose (EC) and hydroxypropylmethylcellulose (HPMC) via the solvent evaporation method. KEY FINDINGS: In an in vitro release study, ERG had an extended release profile, and the release rate of tacrolimus was regulated by the quantity of lactose, EC and HPMC in the formulation. HPMC-containing ERG successfully enhanced and maintained supersaturation of tacrolimus even after 24 h in a supersaturated release study. In contrast, the extent of supersaturation rapidly decreased after 4 h and the concentration nearly reached the same level as that of crystalline tacrolimus at 24 h for ERG without HPMC. In vivo absorption characteristics were compared between ERGs and immediate release (IR) formulation of tacrolimus. Successful and sustained absorption of tacrolimus without reducing bioavailability compared with IR formulation was observed for ERG. CONCLUSIONS: These results suggest the feasibility of combining an EC-based formulation with solid dispersion utilizing HPMC for the extended release of oral formulations and sustained absorption of tacrolimus.