In vivo-in vitro correlation of antitumor activity of heat shock protein 90 (HSP90) inhibitors with a pharmacokinetics/pharmacodynamics analysis using NCI-N87 xenograft mice.

The in vitro antitumor activity (e.g. IC50) of anticancer drugs is important for selecting candidate compounds for in vivo drug efficacy study in the early stage of drug discovery. In this study, we investigated the relationship between in vitro IC50 and in vivo EC50 using six heat shock protein 90 (HSP90) inhibitors.IC50 of each compound was calculated from in vitro cell proliferation assays using the NCI-N87 cancer cell line. Each compound was administered to NCI-N87 xenograft mice, and EC50 and the maximum tumour-killing rate constant were calculated from pharmacokinetics/pharmacodynamics analyses using plasma concentrations and tumour volumes.IC50 obtained in vitro was poorly correlated with EC50 obtained in vivo, while a good correlation (r = 0.856) was observed between them when corrected with the unbound fraction ratio.The results of this study using of HSP90 inhibitors as model compounds suggest importance of the consideration of an unbound fraction to evaluate the relationship between IC50 and EC50. These results will contribute to improvement in the prediction accuracy of in vivo drug efficacy from in vitro activity and the efficiency of drug discovery research.

Factors Causing Post-Anesthetic High Respiratory Resistance in Patients Undergoing Transurethral Resection of Bladder Tumors.

BACKGROUND: In this study, we investigated the causes of high respiratory resistance that is observed after general anesthesia. We focused on respiratory resistance at 5 Hz (R5), which were measured preoperatively and postoperatively. METHODS: Our prospective observational study enrolled 68 patients who underwent transurethral resection of bladder tumors from April to October 2015. Respiratory impedance was measured the day before surgery and immediately after general anesthesia. Participants were divided into 2 groups: Group L (postoperative R5 values < 4.0 cmH2O/L/sec; n = 33) and Group H (postoperative R5 values ≥ 4.0 cmH2O/L/sec; n = 35). Patient background, preoperative R5 values, endotracheal tube or subglottic devices, anaesthetic period, desflurane or sevoflurane, and endotracheal suctioning were compared. RESULTS: Significant parameters were height, inhalation of desflurane, endotracheal suctioning, and preoperative R5 value. Logistic regression showed that endotracheal suctioning and a higher preoperative R5 level increased postoperative respiratory resistance (> 4 cmH2O/L/sec). CONCLUSIONS: The endotracheal suctioning at the end of anesthesia influenced respiratory resistance more than use of the endotracheal tube and desflurane.

Changes in cardiac function and hemodynamics during robot-assisted laparoscopic prostatectomy with steep head-down tilt: a prospective observational study.

OBJECTIVE: Robot-assisted laparoscopic prostatectomy requires the patient to be placed in a steep head-down tilt. The aim of our study was to investigate changes in cardiac index and left ventricular end-diastolic volume in a steep had-down tilt. This is a prospective observational study. We investigated the influence of steep head-down tilt on cardiac function and hemodynamics without fluid restriction in 12 men of American Society of Anesthesiologists physical status I-II undergoing robot-assisted laparoscopic prostatectomy. We measured left ventricular ejection fraction, left ventricular end-diastolic volume and cardiac index by transesophageal echocardiography, cardiac index using a FloTrac® sensor, heart rate and arterial blood pressure, before and 5 min after tilting the operating table. RESULTS: The following variables changed significantly after tilting and establishment of the pneumoperitoneum: left ventricular ejection fraction (before 62.5%, after 55.5%; P = 0.040), systolic blood pressure (before 116 mmHg, after 128 mmHg; P = 0.001) and diastolic blood pressure (before 59 mmHg, after 70 mmHg; P = 0.002). There were no significant changes in cardiac index or left ventricular end-diastolic volume measured by transesophageal echocardiography, or cardiac index by FloTrac® sensor. Left ventricular ejection fraction decreased, whereas cardiac index and left ventricular end-diastolic volume did not change, indicating that steep head-down tilt and pneumoperitoneum during robot-assisted laparoscopic prostatectomy did not greatly influence cardiac function. This study was registered as a clinical study with the Japanese Official Clinical Trial Registry (Trial Registration Number JMA-IIA00158 on 7th January, 2014).

Coronary ostial stenosis detected by transesophageal echocardiography after aortic valve replacement: a case report.

BACKGROUND: Coronary ostial stenosis is a life-threatening complication of aortic valve replacement (AVR). Clinical symptoms usually appear within the first 6 months after AVR (Funada and Mizuno et al., Circ J 70:1312-7, 2006), and perioperative onset is very rare. CASE PRESENTATION: An 80-year-old woman with severe aortic stenosis was scheduled to undergo AVR. AVR using cardiopulmonary bypass (CPB) was successfully carried out. However, 5 min following AVR, signs of left heart failure appeared, and transesophageal echocardiography (TEE) revealed severe hypokinetic left ventricular wall motion. Left coronary ostial stenosis was diagnosed by TEE, and CPB was immediately resumed and coronary artery bypass grafting (CABG) to the left anterior descending branch was performed. CONCLUSIONS: When circulatory failure presents in the acute phase following AVR, onset of coronary ostial stenosis should be considered.

High expression of the Notch ligand Jagged-1 is associated with poor prognosis after surgery for colorectal cancer.

The importance of Notch signaling in colorectal cancer (CRC) carcinogenesis and progression has previously been presented. Increased expression of Jagged-1 (JAG1), a Notch ligand, in CRC has been revealed, but the detailed prognostic significance of JAG1 in CRC has not been determined. Protein expression of JAG1 was examined using immunohistochemistry in 158 CRC specimens. Expression of JAG1 and E-cadherin and their associations with clinicopathologic characteristics, overall survival (OS) and relapse-free survival (RFS) were evaluated. In vitro studies using compounds to regulate intracellular signaling and small interfering RNA to silence JAG1 were performed in a colon cancer cell line. JAG1 expression in cancerous tissues was weak, moderate or strong in 32%, 36% and 32% of specimens, respectively, and correlated with histologic type and T stage. In multivariate analysis, JAG1 expression, histologic type and lymphatic invasion independently correlated with OS and RFS. The combination of high JAG1 expression and low E-cadherin expression had an additive effect toward poorer OS and RFS compared with the low JAG1/high E-cadherin expression subtype. A significant correlation between JAG1 expression and KRAS status was detected in groups stratified as high E-cadherin expression. In vitro studies suggested that RAS-MEK-MAP kinase and the Wnt pathways positively regulated JAG1 expression. Gene silencing with siJAG1 indicated that JAG1 promotes the transition from epithelial to mesenchymal characteristics and cell growth. High expression of JAG1 is regulated by various pathways and is associated with poor prognosis through promoting the epithelial to mesenchymal transition and cell proliferation or maintaining cell survival in CRC.

Unexpected Collection of Pulmonary Venous Blood from a Pulmonary Artery Catheter: A Case Report.

BACKGROUND: Pressure and waveform at the catheter tip are continuously monitored during catheterization of pulmonary artery to ensure accurate catheter placement. We present a case in which pulmonary venous blood was unexpectedly collected from the pulmonary artery catheter despite pulmonary artery pressure and waveform detection at the catheter tip, and describe the measures taken to correct the catheter placement. CASE PRESENTATION: A 74-year-old male underwent mitral valve plasty for cardiac failure caused by mitral valve regurgitation. Preoperative transthoracic echocardiography showed no septal shunt. The pulmonary artery was catheterized through a sheath introducer in the right jugular vein, and the balloon was inflated after insertion of a 15-cm catheter. The catheter was advanced until a pulmonary artery waveform was detected and the pulmonary artery wedge pressure was 21 mmHg at end-expiration. The balloon was deflated and the catheter tip was pulled back 3 cm. Pulmonary artery waveforms and appropriate a and v waves were detected, and transesophageal echocardiography confirmed the location of the catheter tip in the right pulmonary artery. The first collected blood sample had an oxygen partial pressure of 358.8 mmHg, carbon dioxide partial pressure of 20.1 mmHg, and oxygen saturation of 99%, indicating pulmonary venous blood. The pulmonary artery catheter was pulled back 5 cm, but a second blood sample showed the same results. The catheter was pulled back a further 6 cm while the location of the catheter tip was monitored on X-ray fluoroscopy. Blood gas testing through the catheter tip showed oxygen saturation of 84.4 % and oxygen partial pressure of 41.6 mmHg. Surgery was performed uneventfully. Postoperative chest radiographs showed proper placement of the pulmonary artery catheter, but radiographs on postoperative day 1 showed over-insertion, although the insertion length was unchanged. The catheter was removed. The patient was discharged 2 months postoperatively. CONCLUSIONS: Our case highlights the fact that the tip of the pulmonary artery catheter can easily advance into a peripheral branch of the pulmonary artery and cause pulmonary venous blood to be sampled instead of pulmonary arterial blood. A variety of monitoring techniques are needed to confirm accurate catheter placement.

[Postoperative Management and Cost-effectiveness of Epidural Anesthesia in Patients undergoing Abdominal Aortic Replacement Surgery].

BACKGROUND: The use of epidural anesthesia for ablominal aortic replacement surgery may be problematic because of the amount of heparin used during the procedure, which places the patient at increased risk of epidural hematoma. We evaluated its benefits, risks, postoperative outcomes and costs. METHODS: We retrospectively collected data on 93 patients who underwent Y-graft infra-renal abdominal aortic replacement at our institution between 2008 and 2010. All patients were admitted to the intensive care unit (ICU) for postoperative care. We compared the mortality rate, the time until extubation, length of ICU and postoperative hospital stay, and ICU cost of those who received epidural anesthesia comparing with those who did not. RESULTS: Thirty-two of the 93 patients (34.4%) received epidural anesthesia, which was used for 2-5 (mean ± SD ; 3.2 ± 0.8) postoperative days. Postoperative mortality during the 2-year period was 3.3% in the group that did not receive epidural anesthesia (two patients) compared with 3.1% (one patient) in the epidural group (P = 1.00). Postoperative respiratory disorders were recorded in 1.6% of patients who did not receive an epidural (one patient) compared with 6.3% (two patients) in those that did (P = 0.27). There were no reports of epidural hemorrhage, hematoma or infection. Patients with epidurals were extubated earlier than those in the non-epidural group (mean ± standard deviation 5.5 ± 7.2 hours versus 11.6 ± 7.9 hours, respectively P < 0.001), but there were no significant differences between the two groups in terms of ICU cost or length of ICU and postoperative hospital stay. CONCLUSIONS: Epidural anesthesia during abdominal aortic replacement facilitated more rapid extubation, but did not appear to influence other aspects of patient recovery or ICU costs.

Effect of differences in extubation timing on postoperative care following abdominal aortic replacement surgery: a comparison study.

BACKGROUND: Abdominal aortic replacement requires an extensive incision and strict blood pressure control, making rapid extubation of the tracheal tube and pain management difficult. The effects of extubation timing on the postoperative course and medical costs in the intensive care unit (ICU) were analyzed. METHODS: Patients who underwent elective abdominal aortic replacement were evaluated retrospectively. Patients were divided into those extubated on the day of surgery (Group A) and those extubated later (Group B). Group A was subdivided into extubation in the operating room (Group A1) or in the ICU (Group A2). Intubation time in the ICU, postoperative ICU stay, hospital stay, and total ICU expenses were compared among the four groups. RESULTS: Of the 191 patients, 95 were extubated on the day of surgery (Group A) and 96 later (Group B). The two groups differed in age and percutaneous coronary intervention history. Surgery and anesthesia durations, intraoperative infusion volume, and intraoperative bleeding amounts differed significantly in the two groups. Epidural anesthesia was given more frequently in Group A. Mean intubation time in the ICU (2.6 ± 2.8 vs 17.4 ± 5.1 hours, P < 0.01), the ICU stay (2.1 ± 0.3 vs 2.4 ± 0.8 days, P < 0.01), and the hospital stay (16.4 ± 5.2 vs 20.2 ± 12.5 days, P = 0.02) were significantly shorter, and total ICU expenses were significantly lower (1,036 ± 307 vs 1,565 ± 1,072 dollars, P < 0.01), in Group A than in Group B. Of the 95 patients in Group A, 34 were extubated in the operating room (Group A1) and 61 in the ICU (Group A2). Arrhythmia, epidural anesthesia, and the amount of intraoperative infusion amount were significantly higher, and the percentage of women significantly lower, in Group A1 (vs Group A2). Postoperative ICU and hospital stays and the ICU costs were not significantly different. CONCLUSION: Tracheal tube extubation on the day of abdominal aortic replacement surgery resulted in better postoperative course and lower costs than when extubation occurred later. Patients extubated in the operating room or the ICU on the day of surgery had similar postoperative courses and costs.

[Anesthetic Management of One-stage Intravenous Leiomyomatosis Resection Extending to the Right Ventricle].

We report a case of 71-year-old female with intravenous leiomyomatosis (IVL) extending to the right ventricle. She was operated on successfully by one-stage approach involving thoracotomy and laparotomy. The important question was whether to perform IVL extraction first, or hysterectomy first; performing hysterectomy before IVL extraction may increase the risk of postoperative infection such as mediastinitis, as well as the risk of intraperitoneal hemorrhage during cardiopulmonary bypass (CPB) and tumor embolism. On the other hand, if IVL extraction is performed first, there is a possibility of bleeding during hysterectomy following CPB. Moreover, in a case of malignant disease, CPB might increase the risk of systemic metastasis. In the present case, IVL extraction was performed first, considering that hysterectomy before IVL extraction would increase the risk of intraoperative complications, and leading to a successful surgery without any problems. In rare cases, such as this one, it is important that surgeons and anesthesiologists recognize the importance of cooperation and careful surgical planning to decrease the perioperative risks.

[Discrepancy in the length of smoking cessation between surgeon's and anesthesiologist's records in relation to hypoxia during one-lung ventilation].

BACKGROUND: Smoking cessation before pulmonary surgery is essential for preventing respiratory complications associated with operation and anesthesia. We compared patients' smoking habits and length of smoking cessation based on respiratory surgeon's and anesthesiologist's records. METHODS: We retrospectively surveyed 68 patients who underwent elective operation under one-lung ventilation (OLV) with respect to the Brinkmann index, smoking cessation period, and incidence of hypoxia during OLV. RESULTS: Of the 68 patients, 38 had a history of smoking, with no difference in the Brinkmann index according to respiratory surgeons and anesthesiologists. Of the 38 patients, 6 had inconsistent records regarding the length of smoking cessation. The smoking cessation period was significantly longer according to respiratory surgeons (17.5 days (median)) compared to that according to anesthesiologists [2.0 days (median), P < 0.05). The incidence of hypoxia (SP(O2) < 90%) was significantly higher in these patients (4 of 6), relative to those with no discrepancy (2 of 32, P < 0.05). CONCLUSIONS: Accurate information regarding the length of smoking cessation before surgery is difficult to obtain. The incidence of hypoxia during OLV was significantly higher in patients with a discrepancy regarding the length of smoking cessation between respiratory surgeon's and anesthesiologist's records.

[One-lung ventilation using dexmedetomidine in an emphysema patient with pneumothorax due to metastatic lung cancer].

We report a case of double-lumen tube intubation and intraoperative one-lung ventilation under spontaneous breathing with continuous dexmedetomidine administration. A 61-year-old man developed pneumothorax due to multiple metastatic cancer, had multiple bilateral bullae, and underwent bullae resection under general anesthesia. An epidural catheter was placed at T8-9. Under dexmedetomidine sedation and regional anesthesia with lidocaine, a double-lumen tube was inserted with a Macintosh laryngoscope. The patient was under one-lung ventilation with spontaneous breathing during the operation. There were no complications from one-lung ventilation and the patient was extubated in the operating room. One-lung ventilation, which preserves spontaneous breathing, under dexmedetomidine sedation is considered effective for preventing barotrauma in patients with multiple metastatic cancer.

[Successful double-lumen tube insertion using Pentax-AWS Airwayscope with an infant-sized intlock in a rheumatoid arthritis patient with restricted mouth opening and head tilting].

Successful tracheal intubation with a double-lumen tube was achieved using Pentax-AWS Airwayscope (AWS) with an infant-size Intlock in a patient with restricted mouth opening and head tilting. A 78-year-old woman with rheumatoid arthritis was scheduled for extended thymectomy under general anesthesia, with anticipated difficult airway. Sufficient mask ventilation with the jaw-thrust maneuver was achieved. The laryngoscopic view was defined as grade III (Cormack & Lehane's classification)with Macintosh laryngoscope. The AWS with an infant-size Intlock facilitated visualization of the glottis, leading to a successful placement of a 32-Fr double-lumen tube under the guidance of the AWS image. Double-lumen tube insertion assisted by the AWS with an infant-size Intlock may be useful for difficult airway management in patients with restricted mouth opening and head tilting.

Assessing the impact of HER2 status on the antitumor activity of an HSP90 inhibitor in human tumor xenograft mice using pharmacokinetic-pharmacodynamic modeling.

The purpose of this study is to assess the impact of human epidermal growth factor receptor 2 (HER2) status on the antitumor activity of CH5164840, an orally available heat shock protein 90 (HSP90) inhibitor, using pharmacokinetic-pharmacodynamic modeling. Athymic mice, each implanted with one of eight human tumor xenografts, were treated with CH5164840 once daily at doses of 3.13 to 50 mg/kg. Plasma concentrations of CH5164840 were described by a one-compartment model with first-order absorption rate. Time profiles of tumor growth inhibition in the eight xenograft models were well captured by an indirect response model with a maximum tumor-killing rate constant (Emax model). Threshold plasma concentrations for tumor stasis, which are determined by multiple pharmacodynamic parameters, Emax, EC50 and tumor growth rate constant, were significantly lower in HER2-positive tumors (1.96-3.85 µM) than in HER2-negative tumors (4.48-23.4 µM). The results suggest that CH5164840 was more efficacious in HER2-positive tumors than in HER2-negative tumors in terms of the lower effective concentration of the drug in preclinical animal models.

Design and synthesis of 2-amino-6-(1H,3H-benzo[de]isochromen-6-yl)-1,3,5-triazines as novel Hsp90 inhibitors.

A novel series of 2-amino-1,3,5-triazines bearing a tricyclic moiety as heat shock protein 90 (Hsp90) inhibitors is described. Molecular design was performed using X-ray cocrystal structures of the lead compound CH5015765 and natural Hsp90 inhibitor geldanamycin with Hsp90. We optimized affinity to Hsp90, in vitro cell growth inhibitory activity, water solubility, and liver microsomal stability of inhibitors and identified CH5138303. This compound showed high binding affinity for N-terminal Hsp90α (Kd=0.52nM) and strong in vitro cell growth inhibition against human cancer cell lines (HCT116 IC50=0.098µM, NCI-N87 IC50=0.066µM) and also displayed high oral bioavailability in mice (F=44.0%) and potent antitumor efficacy in a human NCI-N87 gastric cancer xenograft model (tumor growth inhibition=136%).

Enhanced antitumor activity of erlotinib in combination with the Hsp90 inhibitor CH5164840 against non-small-cell lung cancer.

Inhibition of heat shock protein 90 (Hsp90) can lead to degradation of multiple client proteins, which are involved in tumor progression. Epidermal growth factor receptor (EGFR) is one of the most potent oncogenic client proteins of Hsp90. Targeted inhibition of EGFR has shown clinical efficacy in the treatment of patients with non-small-cell lung cancer (NSCLC). However, primary and acquired resistance to the existing EGFR inhibitors is a major clinical problem. In the present study, we investigated the effect of the novel Hsp90 inhibitor CH5164840 on the antitumor activity of erlotinib. The NSCLC cell lines and xenograft models were treated with CH5164840 and erlotinib to examine their mechanisms of action and cell growth inhibition. We found that CH5164840 showed remarkable antitumor activity against NSCLC cell lines and xenograft models. The addition of CH5164840 enhanced the antitumor activity of erlotinib against NCI-H292 EGFR-overexpressing xenograft models. Phosphorylation of Stat3 increased with erlotinib treatment in NCI-H292 cells, which was abrogated by Hsp90 inhibition. Furthermore, in a NCI-H1975 T790M mutation erlotinib-resistant model, CH5164840 enhanced the antitumor activity of erlotinib despite the low efficacy of erlotinib treatment alone. In addition, ERK signaling was effectively suppressed by combination treatment with erlotinib and CH5164840 in a NCI-H1975 erlotinib-resistant model. Taken together, these data indicate that CH5164840 has potent antitumor activity and is highly effective in combination with erlotinib against NSCLC tumors with EGFR overexpression and mutations. Our results support the therapeutic potential of CH5164840 as a Hsp90 inhibitor for combination therapy with EGFR-targeting agents against EGFR-addicted NSCLC.

Design and synthesis of novel macrocyclic 2-amino-6-arylpyrimidine Hsp90 inhibitors.

Macrocyclic compounds bearing a 2-amino-6-arylpyrimidine moiety were identified as potent heat shock protein 90 (Hsp90) inhibitors by modification of 2-amino-6-aryltriazine derivative (CH5015765). We employed a macrocyclic structure as a skeleton of new inhibitors to mimic the geldanamycin-Hsp90 interactions. Among the identified inhibitors, CH5164840 showed high binding affinity for N-terminal Hsp90α (K(d)=0.52nM) and strong anti-proliferative activity against human cancer cell lines (HCT116 IC(50)=0.15µM, NCI-N87 IC(50)=0.066µM). CH5164840 displayed high oral bioavailability in mice (F=70.8%) and potent antitumor efficacy in a HCT116 human colorectal cancer xenograft model (tumor growth inhibition=83%).

Preclinical antitumor activity of the novel heat shock protein 90 inhibitor CH5164840 against human epidermal growth factor receptor 2 (HER2)-overexpressing cancers.

Heat shock protein 90 (Hsp90), a molecular chaperone that plays a significant role in the stability and maturation of client proteins, including oncogenic targets for cell transformation, proliferation, and survival, is an attractive target for cancer therapy. We identified the novel Hsp90 inhibitor, CH5164840, and investigated its induction of oncogenic client protein degradation, antiproliferative activity, and apoptosis against an NCI-N87 gastric cancer cell line and a BT-474 breast cancer cell line. Interestingly, CH5164840 demonstrated tumor selectivity both in vitro and in vivo, binding to tumor Hsp90 (which forms active multiple chaperone complexes) in vitro, and being distributed effectively to tumors in a mouse model, which, taken together, supports the decreased levels of phosphorylated Akt by CH5164840 that we observed in tumor tissues, but not in normal tissues. As well as being well tolerated, the oral administration of CH5164840 exhibited potent antitumor efficacy with regression in NCI-N87 and BT-474 tumor xenograft models. In addition, CH5164840 significantly enhanced antitumor efficacy against gastric and breast cancer models when combined with the human epidermal growth factor receptor 2 (HER2)-targeted agents, trastuzumab and lapatinib. These data demonstrate the potent antitumor efficacy of CH5164840 when administered alone, and its significant combination efficacy when combined with trastuzumab or lapatinib, supporting the clinical development of CH5164840 as an Hsp90 inhibitor for combination therapy with HER2-targeted agents against HER2-overexpressing tumors.

Effects of Selected Anionic ß-Cyclodextrins on Persistence of Blood Glucose Lowering by Insulin Glargine after Subcutaneous Injection to Rats.

Insulin glargine is a synthetic long-acting insulin product used for patients with diabetes mellitus. In this study, to obtain the further desirable blood-glucose lowering profile of insulin glargine, we investigated the effects of ß-cyclodextrin sulfate (Sul-ß-CyD) and sulfobutylether ß-cyclodextrin (SBE7-ß-CyD) on physicochemical properties of insulin glargine and pharmacokinetics/pharmacodynamics of insulin glargine after subcutaneous injection to rats. Sul-ß-CyD and SBE7-ß-CyD increased solubility of insulin glargine. SBE7-ß-CyD suppressed the formation of oligomer and enhanced the dissolution rate of insulin glargine from its precipitate, compared to that of Sul-ß-CyD. Additionally, we revealed that after subcutaneous administration of an insulin glargine solution, SBE7-ß-CyD, but not Sul-ß-CyD, increased bioavailability and sustained the blood-glucose lowering effect, possibly due to the inhibitory effects of SBE7-ß-CyD on the enzymatic degradation at the injection site. These results suggest that SBE7-ß-CyD could be a useful excipient for sustained release of insulin glargine.

Lead generation of heat shock protein 90 inhibitors by a combination of fragment-based approach, virtual screening, and structure-based drug design.

Heat shock protein 90 (Hsp90) is a molecular chaperone which regulates maturation and stabilization of its substrate proteins, known as client proteins. Many client proteins of Hsp90 are involved in tumor progression and survival and therefore Hsp90 can be a good target for developing anticancer drugs. With the aim of efficiently identifying a new class of orally available inhibitors of the ATP binding site of this protein, we conducted fragment screening and virtual screening in parallel against Hsp90. This approach quickly identified 2-aminotriazine and 2-aminopyrimidine derivatives as specific ligands to Hsp90 with high ligand efficiency. In silico evaluation of the 3D X-ray Hsp90 complex structures of the identified hits allowed us to promptly design CH5015765, which showed high affinity for Hsp90 and antitumor activity in human cancer xenograft mouse models.

Effect of sulfobutyl ether-ß-cyclodextrin on bioavailability of insulin glargine and blood glucose level after subcutaneous injection to rats.

Insulin glargine is the first long-acting basal insulin analogue used for subcutaneous administration once daily in patients with type 1 or type 2 diabetes mellitus. To obtain the further bioavailability and the sustained glucose lowering effect of insulin glargine, in the present study, we investigated the effect of sulfobutyl ether-ß-cyclodextrin (SBE4-ß-CyD), with the degree of substitution of sulfobutyl ether group of 3.9, on pharmaceutical properties of insulin glargine and the release of insulin glargine after subcutaneous injection to rats. SBE4-ß-CyD increased the solubility and suppressed aggregation of insulin glargine in phosphate buffer at pH 9.5, probably due to the interaction of SBE4-ß-CyD with aromatic amino acid residues such as tyrosine of insulin glargine. In addition, SBE4-ß-CyD accelerated the dissolution rate of insulin glargine from its precipitates, compared to that of insulin glargine alone. Furthermore, we revealed that subcutaneous administration of an insulin glargine solution with SBE4-ß-CyD to rats enhanced the bioavailability of insulin glargine and sustained the glucose lowering effect, possibly due to the inhibitory effects of SBE4-ß-CyD on the enzymatic degradation at the injection site. These results suggest that SBE4-ß-CyD can be a useful excipient for sustained release of insulin glargine.