Efficient Drug Loading Method for Poorly Water-Soluble Drug into Bicelles through Passive Diffusion.

The bicelle, a type of solid lipid nanoparticle, comprises phospholipids with varying alkyl chain lengths and possesses the ability to solubilize poorly water-soluble drugs. Bicelle preparation is complicated and time-consuming because conventional drug-loading methods in bicelles require multiple rounds of thermal cycling or co-grinding with drugs and lipids. In this study, we proposed a simple drug-loading method for bicelles that utilizes passive diffusion. Drug-unloaded bicelles were placed inside a dialysis device and incubated in a saturated solution of ketoconazole (KTZ), which is a model drug. KTZ was successfully loaded into bare bicelles over time with morphological changes, and the final encapsulated concentration was dependent on the lipid concentration of the bicelles. When polyethylene glycol (PEG) chains of two different lengths (PEG2K and 5K) were incorporated into bicelles, PEG2k and PEG5k bicelles mitigated the morphological changes and improved the encapsulation rate. This mitigation of morphological changes enhanced the encapsulated drug concentration. Specifically, PEG5k bicelles, which exhibited the greatest prevention of morphological changes, had a lower encapsulated concentration after 24 h than that of PEG2k bicelles, indicating that PEGylation with a longer PEG chain length improved the loading capacity but decreased the encapsulation rate owing to the presence of a hydration layer of PEG. Thus, PEG with a certain length is more suitable for passive loading. Moreover, loading factors, such as temperature and vehicles used in the encapsulation process, affected the encapsulation rate of the drug. Taken together, the passive loading method offers high throughput with minimal resources, making it a potentially valuable approach during early drug development phases.

Preparation of Cubosomes with Improved Colloidal and Structural Stability Using a Gemini Surfactant.

Cubosomes are nanoparticles with bicontinuous cubic internal nanostructures that have been considered for use in drug delivery systems (DDS). However, their low structural stability is a crucial concern for medical applications. Herein, we investigated the use of a gemini surfactant, sodium dilauramidoglutamide lysine (DLGL), which is composed of two monomeric surfactants linked with a spacer to improve the structural stability of cubosomes prepared with phytantriol (PHY). Uniform nanosuspensions comprising a specific mixing ratio of DLGL and PHY in water prepared via ultrasonication were confirmed by using dynamic light scattering. Small-angle X-ray scattering and cryo-transmission electron microscopy revealed the formation of Pn3̅m cubosomes in a range of DLGL/PHY solid ratios between 1 and 3% w/w. By contrast, cubosome formation was not observed at DLGL/PHY solid ratios of 5% w/w or higher, suggesting that excess DLGL interfered with cubosome formation and caused them to transform into small unilamellar vesicles. The addition of phosphate-buffered saline to the nanosuspension caused aggregation when the solid ratio of DLGL/PHY was less than 5% w/w. However, Im3̅m cubosomes were obtained at solid ratios of DLGL/PHY of 6, 7.5, and 10% w/w. The lattice parameters of the Pn3̅m and Im3̅m cubosomes were approximately 7 and 11-13 nm, respectively. The lattice parameters of Im3̅m cubosomes were affected by the concentration of DLGL. Pn3̅m cubosomes were surprisingly stable for 4 weeks at both 25 and 5 °C. In conclusion, DLGL, a gemini surfactant, was found to act as a new stabilizer for PHY cubosomes at specific concentrations. Cubosomes composed of DLGL are stable under low-temperature storage conditions, such as in refrigerators, making them a viable option for heat-sensitive DDS.

Molecular-Level Structural Analysis of siRNA-Loaded Lipid Nanoparticles by 1H NMR Relaxometry: Impact of Lipid Composition on Their Structural Properties.

1H NMR relaxometry was applied for molecular-level structural analysis of siRNA-loaded lipid nanoparticles (LNPs) to clarify the impact of the neutral lipids, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and cholesterol, on the physicochemical properties of LNP. Incorporating DSPC and cholesterol in ionizable lipid-based LNP decreased the molecular mobility of ionizable lipids. DSPC reduced the overall molecular mobility of ionizable lipids, while cholesterol specifically decreased the mobility of the hydrophobic tails of ionizable lipids, suggesting that cholesterol filled the gap between the hydrophobic tails of ionizable lipids. The decrease in molecular mobility and change in orientation of lipid mixtures contributed to the maintenance of the stacked bilayer structure of siRNA and ionizable lipids, thereby increasing the siRNA encapsulation efficiency. Furthermore, NMR relaxometry revealed that incorporating those neutral lipids enhanced PEG chain flexibility at the LNP interface. Notably, a small amount of DSPC effectively increased PEG chain flexibility, possibly contributing to the improved dispersion stability and narrower size distribution of LNPs. However, cryogenic transmission electron microscopy represented that adding excess amounts of DSPC and cholesterol into LNP resulted in the formation of deformed particles and demixing cholesterol within the LNP, respectively. The optimal lipid composition of ionizable lipid-based LNPs in terms of siRNA encapsulation efficiency and PEG chain flexibility was rationalized based on the molecular-level characterization of LNPs. Moreover, the NMR relaxation rate of tertiary amine protons of ionizable lipids, which are the interaction site with siRNA, can be a valuable indicator of the encapsulated amount of siRNA within LNPs. Thus, NMR-based analysis can be a powerful tool for efficiently designing LNP formulations and their quality control based on the molecular-level elucidation of the physicochemical properties of LNPs.

Nanostructure and Molecular-Level Characterization of Aminoalkyl Methacrylate Copolymer and the Impact on Drug Solubilization Ability.

The effects of pH changes and saccharin (SAC) addition on the nanostructure and mobility of the cationic aminoalkyl methacrylate copolymer Eudragit E PO (EUD-E) and its drug solubilization ability were investigated. Small-angle X-ray scattering performed using synchrotron radiation and atomic force microscopy showed that the EUD-E nanostructure, which has a size of approximately several nanometers, changed from a random coil structure at low pH (pH 4.0-5.0) to a partially folded structure at high pH (pH 5.5-6.5). The EUD-E also formed a partially folded structure in a wide pH range of 4.5-6.5 when SAC was present, and the coil-to-globule transition was moderate with pH increase, compared with that when SAC was absent. The equilibrium solubility of the neutral drug naringenin (NAR) was enhanced in the EUD-E solution and further increased as the pH increased. The enlargement of the hydrophobic region of EUD-E in association with the coil-to-globule transition led to efficient solubilization of NAR. The interaction with SAC enhanced the mobility of the EUD-E chains in the hydrophobic region of EUD-E, resulting in changes in the drug-solubilizing ability. 1H high-resolution magic-angle spinning NMR measurements revealed that the solubilized NAR in the partially folded structure of EUD-E showed higher molecular mobility in the presence of SAC than in the absence of SAC. This study highlighted that solution pH and the presence of SAC significantly changed the drug solubilization ability of EUD-E, followed by changes in the EUD-E nanostructure, including its hydrophobic region.

Effect of Drug-Polymer Interactions through Hypromellose Acetate Succinate Substituents on the Physical Stability on Solid Dispersions Studied by Fourier-Transform Infrared and Solid-State Nuclear Magnetic Resonance.

The present study evaluated the specific intermolecular interactions between carbamazepine (CBZ) and substituents of hypromellose acetate succinate (HPMC-AS), as well as the mechanism of inhibition of recrystallization of solid dispersions (SDs) using Fourier-transform infrared (FTIR) and solid-state nuclear magnetic resonance (NMR) spectroscopy. CBZ and HPMC derivatives, including HPMC, hypromellose acetate (HPMC-A), and hypromellose succinate (HPMC-S), were spray-dried to prepare CBZ/polymer spray-dried samples (SPDs). CBZ/HPMC SPD and CBZ/HPMC-A SPD recrystallized within 10 days at 60 °C and 0% relative humidity, whereas CBZ/HPMC-S SPD maintained its amorphous state for a longer period. FTIR and solid-state NMR measurements using 13C cross polarization (CP), 1H single-pulse, and 1H-15N CP-based heteronuclear single quantum correlation filter experiment with very fast magic angle spinning (MAS) at 70 kHz identified molecular interactions in CBZ/polymer SPDs. Although the HPMC backbone and substituents did not interact notably with CBZ and disrupt CBZ-CBZ intermolecular interactions (formed in the amorphous CBZ), acetate and succinate substituents on HPMC-A and HPMC-S disrupted CBZ-CBZ intermolecular interactions through formation of CBZ/polymer interactions. The acetate substituent formed a hydrogen bond with the NH2 group of CBZ, whereas the succinate substituent formed molecular interactions with both the C═O and NH2 groups of CBZ. Formation of relatively strong molecular interactions between CBZ and the succinate substituent followed by disruption of CBZ-CBZ intermolecular interactions effectively stabilized the amorphous state of CBZ in CBZ/HPMC-S SPD. The correlation between CBZ-polymer interactions and ability of polymers to effectively inhibit CBZ recrystallization is reflected in various commercial HPMC-AS. For example, HPMC-AS LF grade, containing higher amounts of the succinate group, was found to effectively inhibit the recrystallization of CBZ through strong molecular interactions as compared with the HPMC-AS HF grade. The present study demonstrated that a detailed investigation of molecular interactions between the drug and the polymer using FTIR and solid-state NMR spectroscopy could contribute to a suitable selection of the SD carrier.

Combination of NMR Methods To Reveal the Interfacial Structure of a Pharmaceutical Nanocrystal and Nanococrystal in the Suspended State.

The detailed structure of a pharmaceutical nanosuspension was investigated using three nuclear magnetic resonance (NMR) methods: solid-state, solution-state, and high resolution-magic angle spinning (HR-MAS) NMR. Carbamazepine (CBZ) and CBZ-saccharin (SAC) cocrystal nanosuspensions were prepared by wet-milling with hydroxypropyl methylcellulose (HPMC) and sodium dodecyl sulfate (SDS) as stabilizing agents. Solid-state 13C NMR indicated the presence of not only the crystalline drug substance but also solid-state HPMC, even though HPMC was used as an aqueous solution to prepare the nanosuspensions. Solution-state 1H NMR of the nanosuspensions with and without ultracentrifugation pretreatment indicated that a fraction of the CBZ, SAC, and SDS formed a solid or semisolid phase on the surface of the nanoparticles and was in equilibrium between the dissolved and undissolved states. 1H HR-MAS NMR was highly effective in detecting and quantifying the semisolid phase on the surface of the nanoparticles. From these comprehensive NMR studies, it was concluded that the nanosuspension was composed of crystalline drug core particles surrounded by a semisolid phase consisting of the drug and stabilizing agents. The semisolid phase on the nanoparticle surface was in equilibrium with the solution phase and contributed to the stabilization of the nanoparticle by steric hindrance and electrostatic repulsion.

Scoring system for the diagnosis of bilateral primary aldosteronism in the outpatient setting before adrenal venous sampling.

OBJECTIVE: The only reliable method for subtyping primary aldosteronism (PA) is adrenal venous sampling (AVS), which is costly and time-consuming. Considering the limited availability of AVS, it would be helpful to obtain information on the diagnosis of bilateral hyperaldosteronism (BHA) from routine tests. We aimed to establish new, simple criteria for outpatients to diagnose BHA from PA before AVS. DESIGN: We retrospectively analysed 82 patients who were diagnosed with PA and underwent AVS. Thirty-seven patients were diagnosed with unilateral hyperaldosteronism (UHA), and 36 with BHA and nine were undetermined. Among the variables that were significantly different between UHA and BHA in the univariate analysis, we chose three variables to be included in multivariate logistic regression models and constructed a subtype prediction score. RESULTS: The subtype prediction score was calculated as follows: 3 points for no adrenal nodules on computed tomography imaging, 2 for serum potassium of ≥3·5 mmol/l and 2 for aldosterone-to-renin ratio of <490 after a captopril challenge test. Receiver operating characteristic curve analysis for the ability to discriminate BHA from UHA showed that a score of 7 points had 50% sensitivity and 100% specificity and a score of 5 points had 67% sensitivity and 94% specificity (area under the curve: 0·922; 95% CI: 0·863-0·980). CONCLUSIONS: Our new, simple criteria specifically distinguished BHA from UHA in the outpatient setting before AVS. Furthermore, not only endocrinologists but also general internists can use this convenient, safe scoring system.

Isotope-Edited Infrared Spectroscopy for Efficient Discrimination between Pharmaceutical Salts and Cocrystals.

Isotope-edited infrared spectroscopy using carboxylic acids selectively labeled with 13C is proposed herein for the efficient discrimination of pharmaceutical salts and cocrystals, whereby proton-transfer probe vibrations are highlighted by isotope shifts. This new technique can accurately discriminate even a confusing salt from a cocrystal for the traditional method, highlighting the diagnostic peaks. In addition, the established technique also provided the OH in-plane bending vibrations corresponding to intermolecular hydrogen bonding at the carbonyl oxygens of the cocrystals. The technique will accelerate the discrimination, which is a critical process in cocrystal development.

Subtype prediction in primary aldosteronism: measurement of circadian variation of adrenocortical hormones and 24-h urinary aldosterone.

OBJECTIVE: Currently, adrenal venous sampling (AVS) is the only reliable method to distinguish unilateral from bilateral hyperaldosteronism in primary aldosteronism (PA). However, AVS is costly and time-consuming compared with simple blood tests. In this study, we conducted a retrospective study to determine whether circadian variation in plasma adrenocortical hormone levels (i.e. aldosterone, cortisol and ACTH) and a 24-h urinary aldosterone could contribute to the clinical differentiation between unilateral hyperaldosteronism (UHA) and bilateral hyperaldosteronism (BHA). DESIGN: In 64 patients who were diagnosed with PA and underwent AVS, 32 and 22 patients were diagnosed with UHA and BHA, respectively. Plasma adrenocortical hormone levels at 0:00, 6:00, 12:00 and 18:00 and 24-h urinary aldosterone under a condition of 6 g daily dietary sodium chloride intake were measured. RESULTS: Baseline plasma aldosterone concentration (PAC) and 24-h urinary aldosterone level in patients with UHA were significantly higher than in patients with BHA, particularly at 6:00. The area under the ROC curve for PAC at 0:00, 6:00, 12:00 and 18:00 and 24-h urinary aldosterone to discriminate UHA and BHA was 0·839 [95% confidence interval (CI); 0·73-0·95], 0·922 (95% CI; 0·85-1·00), 0·875 (95% CI; 0·78-0·97), 0·811 (95% CI; 0·69-0·93), 0·898 (95% CI; 0·81-0·99), respectively. CONCLUSIONS: PAC at different blood sampling times and 24-h urinary aldosterone level may be diagnostically helpful in discriminating between UHA and BHA. We believe that these tests could reduce the number of unnecessary AVS procedures.

Physicochemical Evaluation and Developability Assessment of Co-amorphouses of Low Soluble Drugs and Comparison to the Co-crystals.

To judge the developability and analyze functional mechanism of co-amorphouses, we investigated the physicochemical properties of co-amorphouses and compare the properties with the co-crystals having the same drug and counters. Co-amorphous compounds are a novel approach to improve the physicochemical properties of drugs. A co-amorphous is in an amorphous solid state allowing non-ionic interactions between drug molecules and counter molecules. The co-amorphous compounds composed of itraconazole (ITZ) with the organic carboxyl acid, fumaric acid (FA) or L-tartaric acid (TA), were prepared by mechanical grinding. Potential interactions within ITZ-FA co-amorphous were assessed by Raman spectroscopy. ITZ-FA co-amorphous was not crystallized as the co-crystal or as a single ITZ crystal, suggesting that the amorphous state, like the amorphous solid dispersion, was physically stable and that ITZ-FA co-amorphous was also chemically stable. In contrast, no clear interactions were observed within ITZ-TA co-amorphous, and the co-amorphous was physically stable but chemically unstable. The solubility of the co-amorphous state was much higher than those of ITZ crystal and the co-crystals and was almost identical to that of amorphous ITZ. A co-amorphous compound like ITZ-FA co-amorphous might be feasible to implement in the development of solid drug products and bring some merits compared to the co-crystals, and the function is governed by the interaction between a drug and a counter. The co-amorphous approach may be an effective strategy for drug development and can contribute to the production of novel drugs with improved functions.

Characterization and Quality Control of Pharmaceutical Cocrystals.

Recent active research and new regulatory guidance on pharmaceutical cocrystals have increased the rate of their development as promising approaches to improve handling, storage stability, and bioavailability of poorly soluble active pharmaceutical ingredients (APIs). However, their complex structure and the limited amount of available information related to their performance may require development strategies that differ from those of single-component crystals to ensure their clinical safety and efficacy. This article highlights current methods of characterizing pharmaceutical cocrystals and approaches to controlling their quality. Different cocrystal regulatory approaches between regions are also discussed. The physical characterization of cocrystals should include elucidating the structure of their objective crystal form as well as their possible variations (e.g., polymorphs, hydrates). Some solids may also contain crystals of individual components. Multiple processes to prepare pharmaceutical cocrystals (e.g., crystallization from solutions, grinding) vary in their applicable ingredients, scalability, and characteristics of resulting solids. The choice of the manufacturing method affects the quality control of particular cocrystals and their formulations. In vitro evaluation of the properties that govern clinical performance is attracting increasing attention in the development of pharmaceutical cocrystals. Understanding and mitigating possible factors perturbing the dissolution and/or dissolved states, including solution-mediated phase transformation (SMPT) and precipitation from supersaturated solutions, are important to ensure the bioavailability of orally administrated lower-solubility APIs. The effect of polymer excipients on the performance of APIs emphasizes the relevance of formulation design for appropriate use.

Screening and Characterization of Hydrate Forms of T-3256336, a Novel Inhibitor of Apoptosis (IAP) Protein Antagonist.

Different crystal packing of hydrates from anhydrate crystals leads to different physical properties, such as solubility and stability. Investigation of the potential of varied hydrate formation, and understanding the stability in an anhydrous/hydrate system, are crucial to prevent an undesired transition during the manufacturing process and storage. Only one anhydrous form of T-3256336, a novel inhibitor of apoptosis (IAP) protein antagonist, was discovered during synthesis, and no hydrate form has been identified. In this study, we conducted hydrate screening such as dynamic water vapor sorption/desorption (DVS), and the slurry experiment, and characterized the solid-state properties of anhydrous/hydrate forms to determine the most desirable crystalline form for development. New hydrate forms, both mono-hydrate and hemi-hydrate forms, were discovered as a result of this hydrate screening. The characterization of two new hydrate forms was conducted, and the anhydrous form was determined to be the most desirable development form of T-3256336 in terms of solid-state stability. In addition, the stability of the anhydrous form was investigated using the water content and temperature controlled slurry experiment to obtain the desirable crystal form in the crystallization process. The water content regions of the stable phase of the desired form, the anhydrous form, were identified for the cooling crystallization process.

Plasma free metanephrines in the diagnosis of pheochromocytoma: diagnostic accuracy and strategies for Japanese patients.

Measuring the levels of the plasma free metanephrines (PFMs) represents a recently developed and promising test for the diagnosis of pheochromocytoma in the United States and Europe. As this test has not yet been evaluated in Japan, it is necessary to evaluate the diagnostic efficacy of measuring the levels of PFMs compared with the standard measurement of the urinary excretion of metanephrines (uMNs) whose reliability is well established to detect of pheochromocytoma. A total of 101 Japanese subjects clinically suspected of having pheochromocytoma in were included in this study. Subsequently, we prospectively measured the PFMs levels in all patients, compared with those of biochemical markers of the catecholamine secretion and metabolisms in the plasma and urine. All subjects with adrenal tumors underwent tumor excision. Data were available for 84 of the 101 patients, 47 of whom had histopathologically proven pheochromocytoma and 37 were finally diagnosed with non-pheochromocytoma. The results of comparisons in the accuracy of measurement for diagnosis of pheochromocytoma between PFMs and the urinary excretion of metanephrines (uMNs) were 0.980 VS 0.951 for AUC of receiver operatorating characteristic (ROC) curve, 0.957 VS 0.894 for sensitivity, and 0.973 VS 0.946 for specificity, respectively. Although the differences were small, the results of our study definitely demonstrated that measurement of PFMs was not inferior to standard urinary metanephrines (uMNs) measurement, which is established to be the most reliable biochemical method to detect pheochromocytoma. This study clearly shows measuring the PFMs levels to be a reliable and efficient method for diagnosing pheochromocytoma in Japanese patients, as demonstrated in previous reports.

Monitoring the Dissolution Behavior of Novel Pharmaceutical Cocrystals Consisting of Antimalarial Drug Artemisinin with Probe-Type Low-Frequency Raman Spectrometer.

Artemisinin (ART) is a most promising antimalarial agent. However, its low aqueous solubility limits its oral absorption, resulting in low bioavailability. In this study, we have successfully discovered a novel cocrystal with 2-methyl resorcinol (ART-2MRE) providing improved solubility compared with a previously reported cocrystal with resorcinol (ART-RES). Single crystal X-ray structure analysis revealed that the ART-2MRE cocrystal was composed of ART and 2MRE in a molar ratio of 2 : 1. Though the ART-2MRE and ART-RES cocrystals were found to have similarities in their crystal structures, with one layer of a cocrystal former and two layers of ART arranged in alternating rows, the ART-2MRE cocrystal showed higher dissolution rate than ART-RES cocrystal. In situ real-time low-frequency (LF) Raman monitoring and powder X-ray diffraction (PXRD) measurements of the crystals during the dissolution test proved useful to investigate the dissolution behavior of the cocrystals. Low-frequency Raman monitoring revealed that as dissolution progressed, there was a continuous shift from the peak unique to the ART-2MRE cocrystal to the peak unique to the ART stable form. Similar observations were obtained in PXRD measurements as well. Furthermore, experiments were conducted by adding a polymer to the dissolution test solution to investigate the dissolution behavior under supersaturation, indicating the possibility of differences in the dissolution behavior between the ART-2MRE cocrystal and ART-RES cocrystal. Understanding the dissolution behavior from cocrystals is essential in developing cocrystals.

Single-cell detection and linear discriminant analysis of bacterial Raman spectra in glass filter microholes.

We report a study of micro-Raman spectroscopy towards an optimal approach for single cell measurements for the detection of bacteria by vibrational spectroscopy. The use of glass membrane filters was tested by microfiltration to separate individual bacterial cells. The glass membrane filters were applied to the study of Raman spectral classification analysis. This approach achieved the capture and individual detection of spiked bacterial cells. Linear discriminant analysis (LDA) of Raman spectra measured on glass membrane filters was successfully used to distinguish several bacterial species.

Impact of physicochemical profiling for rational approach on drug discovery.

Solid-state characterization plays a vital role in lead optimization and candidate selection with the appropriate physicochemical properties for proper oral dosage formulation. Aqueous solubility is an important parameter in the successful development of oral dosage formulation since poor aqueous solubility limits absorption. In this study, we summarized an efficient approach using a small amount of sample for solid-state characterization, including thermodynamic solubility, which is defined as physicochemical profiling. By using the physicochemical profiling results of 75 anti-cancer drugs and clinical candidates, we examined the relationship between thermodynamic solubility and molecular structural parameters and assessed the effects of thermodynamic solubility on pharmacokinetic profile for rational soluble drug design. The Log DpH 7.4, aromatic ring count, and hydrogen bond count were good indicators for predicting sparingly soluble compounds that increase the lattice energy because of π-π stacking and hydrogen bonds, resulting in lowered thermodynamic solubility. The level of thermodynamic solubility in simulated intestinal fluid (pH 6.8) in the presence and absence of bile acid, which is required for minimal acceptable bioavailability (>30%), was 1 µg/mL and 10 µg/mL, respectively. Physicochemical profiling, which includes thermodynamic solubility considering its solid-state properties, contributes to rational lead optimization and efficient candidate selection for drug development.

Polymer-inducing chemical degradation of amorphous solid dispersions driven by drug-polymer interactions for physical stabilization.

Intermolecular interactions between active pharmaceutical ingredients (APIs) and carrier polymers are important for the long-term physical stability of amorphous solid dispersions (ASDs). However, the negative impact of intermolecular interactions on chemical stability has rarely been reported. In this study, the relationship between intermolecular interactions and physical and chemical stability was investigated using two ASDs composed of API and hydroxypropyl methylcellulose acetate succinate (HPMCAS) with different stabilities: ASD1 was physically stable but chemically unstable, whereas ASD2 was physically unstable but chemically stable. Ionic-bonding between the pyridine nitrogen in the API and succinyl group in HPMCAS was found in both ASDs. The additional interaction between the succinyl group in HPMCAS and the hydroxyl group in the API was suggested only in ASD1. It was concluded that the additional interaction contributed to the physical stability of ASD1; however, it accelerated the chemical reaction between the succinyl and hydroxyl groups to generate succinyl ester owing to its close proximity. This study shows that the intermolecular interaction between the API and carrier polymer is not always beneficial for chemical stability. Understanding the molecular states of APIs and polymers in ASDs is important for their successful development.

Design and synthesis of pyrrolo[3,2-d]pyrimidine HER2/EGFR dual inhibitors: improvement of the physicochemical and pharmacokinetic profiles for potent in vivo anti-tumor efficacy.

During the course of our studies on a novel HER2/EGFR dual inhibitor (TAK-285), we found an alternative potent pyrrolo[3,2-d]pyrimidine compound (1a). To enhance the pharmacokinetic (PK) profile of this compound, we conducted chemical modifications into its N-5 side chain and conversion of the chemically modified compounds into their salts. Among them, 2cb, the tosylate salt of compound 2c, showed potent HER2/EGFR kinase inhibitory activity (IC(50): 11/11 nM) and cellular growth inhibitory activity (BT-474 cell GI(50): 56 nM) with a good drug metabolism and PK (DMPK) profile. Furthermore, 2cb exhibited significant in vivo antitumor efficacy in both mouse and rat xenograft models with transplanted 4-1ST gastric cancer cell lines (mouse, T/C=0%, 2cb po bid at 100 mg/kg; rat, T/C: -1%, 2cb po bid at 25 mg/kg).

Amorphous characterization of pharmaceutical drug substances enabled by the elastic modulus mapping of atomic force microscope.

The states of amorphous drug and/or newly generated crystalline drug on the surface of amorphous drug samples must be carefully characterized to validate the quality of pharmaceutical amorphous drugs. In this study, we investigated whether individual mechanical properties of amorphous and crystalline drugs could be discerned by an atomic force microscope (AFM) with a mapping. Among mechanical properties, the amorphous and crystal drugs were quantitatively distinguished by elastic modulus using PeakForceTM quantitative nanomechanical mapping. The elastic modulus of the crystals exceeded 10 GPa-significantly higher than that of the amorphous, which was ≤5 GPa in all five model drugs; consequently, ≤200 nm scale crystals were detected on amorphous surfaces. Furthermore, the elastic modulus reflected the difference in the amorphous states between the molten and the solvent-evaporated preparations in the microscopic area, thereby demonstrating the ability of AFM to characterize amorphous states. Taken together, AFM measurements using elastic modulus can be an effective analytical tool to provide microscale mapping and characterization of amorphous surfaces, leading to enhanced amorphous drug development.

Pinpoint modification strategy for stabilization of single guide RNA.

The clustered regularly interspaced short palindromic repeats-CRISPR associated protein9 (CRISPR-Cas9) system, which includes a single guide RNA (sgRNA) and a Cas9 protein, is an emerging and promising gene editing technology that produces specific changes, including insertions, deletions, or substitutions, in desired targets. This approach can be applied in novel therapeutic areas for multiple cancers and genetic diseases, including Parkinson's disease, sickle cell disease, and muscular dystrophy. However, there are many limitations to its potential application to therapeutics. CRISPR-Cas9 activity without side effects, delivery of CRISPR-Cas9 to the target cell within the desired tissue including liver, lungs, brain and muscle and the expression of Cas9 endonuclease in the target cell are key factors in achieving therapeutic efficacy. Generally, single-stranded RNA is immediately degraded in cells and biological fluids such as serum, as chemically unmodified single-stranded RNA shows extremely poor stability against nuclease degradation. To overcome this limitation, sgRNA is chemically modified to obtain a highly stable sgRNA for efficient gene editing in cells and in vivo. Here, we identified the cleavage site of sgRNA for pinpoint modification in biological tissues using mass spectrometry and improved stability of pinpoint modified sgRNA in these fluids. Although improved efficiency provided by modified sgRNA has already been reported, we identified the cleavage site by mass spectrometry and revealed that the stability increased with the pinpoint modification strategy for the first time in this study. In future studies, the efficiency of pinpoint modification strategy for the potential application of sgRNA by systematic routes, including intravenous and subcutaneous administration will be assessed.