Radiotherapy-assisted tumor selective metronomic oral chemotherapy.

Chemotherapy have commonly been used in maximum tolerated dose to completely eradicate the cancer. However, such treatments often failed due to the complex and dynamic nature of cancer. Therefore, it has been suggested that cancer should be treated as a chronic disease, controlling its growth by providing continuous therapeutic pressure for long-term. Such an approach, however, requires a therapy that is non-toxic and orally available with sufficient potency. Herein, we propose a radiotherapy-assisted orally available metronomic apoptosis-targeted chemotherapy, which delivers doxorubicin continuously to the irradiated tumor with high selectivity while causing minimal toxicities to the normal tissues. DEVD-S-DOX/DCK complex is the anticancer prodrug for our strategy that could selectively release doxorubicin in the irradiated tumor tissue with sufficient oral bioavailability. The prodrug was completely inactive by itself, but displayed potent anticancer activity when coupled with radiotherapy. Consequently, the daily oral administration of DEVD-S-DOX/DCK in combination with the low-dose radiotherapy effectively suppressed the growth of tumor in vivo with no significant systemic toxicities despite that the accumulated dose of doxorubicin exceeded 150 mg/kg. Therefore, the our novel therapy using DEVD-S-DOX/DCK complex is considered as an outstanding treatment option for treating cancer for long-term attributed to its oral availability and low-toxicity profile as well as the potent anticancer effect.

Systemic PEGylated TRAIL treatment ameliorates liver cirrhosis in rats by eliminating activated hepatic stellate cells.

UNLABELLED: Liver fibrosis is a common outcome of chronic liver disease that leads to liver cirrhosis and hepatocellular carcinoma. No US Food and Drug Administration-approved targeted antifibrotic therapy exists. Activated hepatic stellate cells (aHSCs) are the major cell types responsible for liver fibrosis; therefore, eradication of aHSCs, while preserving quiescent HSCs and other normal cells, is a logical strategy to stop and/or reverse liver fibrogenesis/fibrosis. However, there are no effective approaches to specifically deplete aHSCs during fibrosis without systemic toxicity. aHSCs are associated with elevated expression of death receptors and become sensitive to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced cell death. Treatment with recombinant TRAIL could be a potential strategy to ameliorate liver fibrosis; however, the therapeutic application of recombinant TRAIL is halted due to its very short half-life. To overcome this problem, we previously generated PEGylated TRAIL (TRAILPEG ) that has a much longer half-life in rodents than native-type TRAIL. In this study, we demonstrate that intravenous TRAILPEG has a markedly extended half-life over native-type TRAIL in nonhuman primates and has no toxicity in primary human hepatocytes. Intravenous injection of TRAILPEG directly induces apoptosis of aHSCs in vivo and ameliorates carbon tetrachloride-induced fibrosis/cirrhosis in rats by simultaneously down-regulating multiple key fibrotic markers that are associated with aHSCs. CONCLUSION: TRAIL-based therapies could serve as new therapeutics for liver fibrosis/cirrhosis and possibly other fibrotic diseases. (Hepatology 2016;64:209-223).

Preparation of Oxaliplatin-Deoxycholic Acid Derivative Nanocomplexes and In Vivo Evaluation of Their Oral Absorption and Tumor Growth Suppression.

To prepare orally available oxaliplatin (OXA), nanocomplexes were formed by ionic conjugation of OXA with the deoxycholic acid derivative, Nalpha-deoxycholy-L-lysyl-methylester (DCK), as an oral absorption enhancer. We characterized the DCK-conjugated OXA nanocomplexes by differential scanning calorimetry, particle size determination, and morphological analysis. To evaluate the effects of DCK on the intestinal permeability of OXA, we assessed the solubilities and partition coefficients of OXA and the OXA/DCK nanocomplex, and then conducted in vitro artificial intestinal membrane and Caco-2 cell permeability studies. Finally, bioavailability in rats and tumor growth inhibition in the squamous cell carcinoma (SCC7) model after oral administration of the OXA/DCK nanocomplex were investigated compared to pure OXA. Analysis of the ionic complex formation of OXA with DCK revealed that OXA existed in an amorphous form within the complex, resulting in for- mation of nanocomp;exes (35.05 +/- 4.48 nm in diameter). The solubility of OXA in water was approximately 7.07 mg/mL, whereas the water solubility of OXA/DCK was approximately 2.04 mg/mL and its partition coefficient was approximately 1.2-fold higher than that of OXA. The in vitro intestinal membrane permeability of OXA was significantly enhanced by complex formation with DCK. An in vivo pharmacokinetic study revealed that the Cm value of the OXA/DCK nanocomplex was 3.18-fold higher than that of OXA (32.22 +/- 10.24 ng/mL), and the resulting oral bioavailability of the OXA/DCK nanocomplex was 39.3-fold more than that of OXA. Furthermore, the oral administration of OXA/DCK significantly inhibited tumor growth in SCC7-bearing mice, and maximally inhibited tumor volume by 54% compared to the control. These findings demonstrate the therapeutic potential of the OXA/DCK nanocomplex as an oral anti-cancer therapy because it improves the oral absorption of OXA, which may improve patient compliance and expand the therapeutic applications of OXA to the prevention of recurrence and metastasis.

Preclinical safety evaluation of low molecular weight heparin-deoxycholate conjugates as an oral anticoagulant.

The preclinical safety of a newly developed oral anticoagulant, the low molecular weight heparin-deoxycholate conjugate (OH09208), was evaluated by a comprehensive evaluating program in compliance with standard guidelines. The single dose oral toxicity study in rats receiving 2000 and 5000 mg kg(-1) of OH09208 did not reveal any mortality, unusual body weight changes or necropsy findings. The results of the 4-week oral toxicity study with a 4-week recovery program in rats receiving OH09208 in doses of 100, 300 and 1000 mg kg(-1) day(-1) did not reveal any mortality, or indicate any unusual clinical signs, or show any toxicokinetic relationships to the administration of OH09208. Although the increase in liver enzymes in one male dog treated with 300 mg kg(-1) day(-1) and one female dog treated with 1000 mg kg(-1) day(-1) could not be excluded from the effect of the test substance, no other toxicologically significant changes were observed in the 4-week oral toxicity study with a 4-week recovery in beagle dogs. Thus, while the no-observed-adverse-effect level value from the 4-week study in both male and female rats was 1000 mg kg(-1) day(-1), those from the 4-week study in male and female beagle dogs were 300 and 1000 mg kg(-1) day(-1), respectively. Furthermore, OH09208 did not induce anaphylactic reactions in guinea pigs, micronucleated bone marrow cells in male ICR mice, chromosomal aberration in Chinese hamster lung cell lines, bacterial reverse mutation, and any abnormalities in hERG current assay, mouse central nervous system and dog cardiovascular studies. Overall, there were no unexpected toxicities in this preclinical study that might have precluded the safe administration of OH09208 to humans.

Safety studies on intravenous infusion of a potent angiogenesis inhibitor: taurocholate-conjugated low molecular weight heparin derivative LHT7 in preclinical models.

CONTEXT: As a class of angiogenesis inhibitors, heparin conjugates have shown significant effectiveness in several studies. OBJECTIVES: The purpose of our current study is to evaluate the effectiveness and safety of infusing the conjugate of low molecular weight heparin and taurocholate (LHT7), which has been developed as a potent angiogenesis inhibitor. METHODS: To evaluate its safety, the method of intravenous infusion was compared with its i.v. bolus administration. Intravenous infusion was administered at a rate of 400 µl/min/kg of body weight for 30 min. Pharmacokinetic (PK) analysis, organ accumulation, and plasma concentration profiles of LHT7 were measured. The anticancer effect of LHT7 was evaluated in murine and human xenograft models, and preclinical studies were performed in SD rats and beagle dogs. RESULTS: The results of the PK studies showed reduced organ accumulation in mice and the AUC(0-96 h) (area under the curve) was increased up to 1485 ± 125 h × µg/ml. The efficacy, at dose 1 mg/kg/2 d was higher for i.v. infusion than for i.v. bolus administration in both murine and human cancer models. The preclinical studies showed the safety dose of LHT7 is less than 20 mg/kg in SD rats and in the next safety analysis in beagle dogs showed that there were no organ-specific adverse effects in higher doses, such as, 12 mg/kg. LHT7 showed sustained effects with minimized adverse events when administered through i.v. infusion. CONCLUSIONS: LHT7 (i.v. infusion) could be safely used for further clinical development as a multi-targeting anti-angiogenic agent.

Absorption Mechanism of a Physical Complex of Monomeric Insulin and Deoxycholyl-l-lysyl-methylester in the Small Intestine.

Currently, oral administration of insulin still remains the best option to avoid the burden of repeated subcutaneous injections and to improve its pharmacokinetics. The objective of the present investigation was to demonstrate the absorption mechanism of insulin in the physical complexation of deoxycholyl-l-lysyl-methylester (DCK) for oral delivery. The oral insulin/DCK complex was prepared by making a physical complex of insulin aspart with DCK through ion-pair interaction in water. For the cellular uptake study, fluorescein-labeled insulin or DCK were prepared according to a standard protocol and applied to Caco-2 or MDCK cell lines. For the PK/PD studies, we performed intrajejunal administration of different formulation of insulin/DCK complex to diabetic rats. The resulting insulin and DCK complex demonstrated greatly enhanced lipophilicity as well as increased permeation across Caco-2 monolayers. The immunofluorescence study revealed the distribution of the complex in the cytoplasm of Caco-2 cells. Moreover, in the apical sodium bile acid transporter (ASBT) transfected MDCK, the insulin/DCK complex showed interaction with ASBT, and also demonstrated absorption through passive diffusion. We could not find that any evidence of endocytosis in relation to the uptake of insulin complex in vitro. In the rat intestine model, the highest absorption of insulin complex was observed in the jejunum at 1 h and then in the ileum at 2-4 h. In PK/PD study, the complex showed a similar PK profile to that of SC insulin. Overall, the study showed that the effect of DCK on enhancing the absorption of insulin resulted from transcellular processes as well as bile acid transporter activity.

Combinational chemoprevention effect of celecoxib and an oral antiangiogenic LHD4 on colorectal carcinogenesis in mice.

To achieve a clinically rational regimen for cancer chemoprevention with improved efficacy and safety, the combination effect of celecoxib and newly developed oral angiogenesis inhibitor, LHD4, on chemoprevention was evaluated. The chemopreventive effects of celecoxib, LHD4, and the combination of celecoxib and LHD4 were evaluated in a murine colorectal carcinogenesis model. After 17 experimental weeks, mouse colon tissues were collected and examined in terms of polyp volume and degree of carcinogenesis, inflammation, and angiogenesis. Mice in the celecoxib-treated or LHD4-treated groups had total polyp volumes of 47.0±9.7 and 120.1±45.2 mm, respectively, which represented decreases of 65.6 and 22.3% from the control (154.5±33.5 mm). However, the polyp volume in the combination group was 22.8±9.3 mm, a decrease of 85.2% from the control. In the comparison of carcinogenesis, the percentage of normal tissue (i.e. excluding proliferative tissue) was found to be 40.6% in the control, 51.7% in the celecoxib, 56.9% in the LHD4, and 81.7% in the combination group. In accordance with attenuated carcinogenesis, both inflammation and angiogenesis were also well controlled. Together, these results suggest that the combinatory use of celecoxib and a newly developed oral heparin conjugate could be a promising regimen for chemoprevention by intervening in both inflammation and angiogenesis.

Oral delivery of ionic complex of ceftriaxone with bile acid derivative in non-human primates.

PURPOSE: Since the absorption of ceftriaxone (CTO) in the intestine is restricted by its natural physiological characteristics, we developed a series of small synthetic compounds derived from bile acids to promote the absorption of CTO in the gastrointestinal tract. METHODS: Several bile acid derivatives were screened by measuring water solubility and partition coefficient of their complexes with CTO. The pharmacokinetic parameters of the selected CTO/HDCK ionic complex in monkeys were evaluated. The absorption pathway of CTO/HDCK complex was evaluated using Caco-2 cells and MDCK cells transfected with ASBT gene. RESULTS: HDCK enhanced the apparent membrane permeability of CTO 5.8-fold in the parallel artificial membrane permeability assay model. CTO/HDCK complex permeated Caco-2 cell via transcellular pathway, and interaction of the HDCK complex with ASBT was important to enhance uptake. When CTO/HDCK (equivalent to 50 mg/kg of ceftriaxone) formulated with lactose, poloxamer 407 and Labrasol was orally administered to monkeys, its maximum plasma concentration was 19.5 ± 1.8 µg/ml and oral bioavailability 28.5 ± 3.1%. CONCLUSIONS: The CTO/HDCK formulation could enhance oral bioavailability of CTO in non-human primates. This oral formulation could be an alternative to injectable CTO with enhanced clinical effects.

Anticoagulant efficacy of solid oral formulations containing a new heparin derivative.

The need for an efficacious and safe oral anticoagulant that does not require monitoring has been largely unmet. Many efforts have centered on preparing orally available heparin to improve patient compliance. In this study, novel orally active heparin derivatives (LHD), i.e. low molecular weight heparin (LMWH) conjugated with deoxycholic acid (DOCA), were evaluated in vitro and in vivo for their enhancement effect of oral heparin absorption. After oral administration of 10 mg/kg of water-soluble LHD, Ws-LHD1.5 showed optimum oral efficacy and its bioavailability was about 24% in rats. The oral absorption of LHD1.5 was also enhanced by several solubilizers, among which Poloxamer 407 provided the best results. When 5 mg/kg of LHD1.5 with Poloxamer 407 was orally administered to monkeys, the maximum anti-FXa activity in plasma was 0.26 +/- 0.04 IU/mL and its bioavailability was 17.4%. In a rat thrombosis model, 5 mg/kg of orally administered LHD1.5 formulated with Poloxamer reduced thrombus formation by 63.9 +/- 16.6%, which was higher than the efficacy of clinically used enoxaparin (49.4 +/- 17.8% at 100 IU/kg, sc). Considering the oral absorption efficacy and therapeutic effect, the conjugation ratio was optimized as about 1.5 molecules of DOCA per mole of heparin. Therefore, LHD1.5 with Poloxamer 407 can be further formulated as a solid oral anticoagulant drug.

Diabetes correction in pancreatectomized canines by orally absorbable insulin-deoxycholate complex.

Oral insulin therapy has great potential benefits over conventional therapy for diabetic patients as well as mimicking the physiological fate of insulin. Here we evaluated the characteristics of insulin and deoxycholate-based synthetic N(alpha)-deoxycholyl-L-lysyl-methylester (DCK) complex, and diabetes correction in pancreatectomized canines after oral administration. After the insulin/DCK complexation was made, the insulin's folding structure, stability against digestive enzymes, lipophilicity and permeability to Caco-2 monolayer were evaluated in vitro. Diabetic canines were kept under fasting conditions, and Eudragit-coated gelatin capsules containing insulin or insulin/DCK powder were singly or triply administered. Evaluation of glucodynamics, pharmacokinetics, oral glucose tolerance test (OGTT) and reproducibility were carried out. After complexation with DCK, the folding structure of insulin did not become denatured and the resistance against digestive enzymes was powerfully improved. The lipophilicity and permeability of insulin/DCK (coupling ratio up to 1:10) were also highly increased. The insulin/DCK complex, administered orally into diabetic canines at the doses of 21, 42, and 81 IU/kg, reduced the plasma glucose levels by about 28%, 44% and 67%, respectively, while the plasma insulin concentrations increased. During OGTT, insulin/DCK nearly maintained the normoglycemic state in the diabetic canines, whereas the hyperglycemic state of placebo-treated controls was not corrected. During oral administration of insulin/DCK, it repetitively showed similar therapeutic efficacy in diabetic canines for 3 days. The therapeutic efficacy of insulin/DCK was exhibited in its digestive enzyme resistance, deoxycholate-based lipophilicity for enhancing permeability and intact insulin delivery without chemical modification, providing potential oral therapeutic remedy as an alternative to injectable insulin medication.

Polyproline-type helical-structured low-molecular weight heparin (LMWH)-taurocholate conjugate as a new angiogenesis inhibitor.

Although heparin can regulate angiogenesis, tumor growth and metastasis, its clinical application, as well as that of low-molecular heparin (LMWH), for treating cancer are limited because of heparin's anticoagulant activity and risk of hemorrhages. LMWH-taurocholate conjugates (LHT7), which have low anticoagulant activity, were synthesized. The structural property of LHT was evaluated by circular dichroism and the binding affinity of LHT7 to vascular endothelial growth factor 165 (VEGF(165)) was measured by isothermal titration calorimetry. The inhibitory effect of LHT7 on VEGF-mediated KDR (VEGF-receptor 2) phosphorylation in Human umbilical vein endothelial cells was evaluated. The VEGF(165) dependent Matrigel plug assay was performed to verify the antiangiogenic potential of LHT7 on a VEGF(165) inhibitor. Finally, tumor growth inhibition effects of LHT7 on SCC7 and the survival rate of animal models were investigated. Moreover, MDA-MB231 xenograft mouse model was additionally used to confirm the therapeutic effect of LHT7 on human breast cancer cell line. As a result, LHT7 which has 12.7% of anticoagulant activity of the original LMWH showed a peculiar polyproline-type helical structure. LHT7 binds to VEGF strongly and inhibits VEGF dependent KDR phosphorylation. The results of Matrigel plug assay proved LHT7 as a strong antiangiogenic agent inhibiting VEGF(165). Remarkably, LHT7 showed a significant tumor growth inhibition potential on SCC7 with an increased survival rate. LHT7 also delayed tumor growth in MDA-MB231 human breast cancer cell lines.

Oral pemetrexed facilitates low-dose metronomic therapy and enhances antitumor efficacy in lung cancer.

There is a growing interest in preclinical research to consider low-dose metronomic chemotherapy as antiangiogenic cancer treatment. Oral metronomic therapy, in particular, has shown much promise with its ease of daily administration and higher therapeutics window. In that regard, we developed oral pemetrexed using the physical complex with the bile acid enhancers (DCK). In a caco-2 permeability study, the oral pemetrexed/DCK complex had significantly higher drug uptake, and inhibited efflux transporter activity as well. We further observed that the mechanism of oral drug uptake was related to transcellular along with bile acid transporter mediated pathways. The oral administration of drug complex in rats revealed high bioavailability (22.37%) and extended mean residence time. Using SCC7 and A549 xenograft models, we demonstrated that antitumor effects from daily oral metronomic pemetrexed significantly reduced tumor in a dose-dependent manner. The antitumor activity of oral pemetrexed/DCK complex plus cisplatin was superior to both monotherapies. The xenograft study also revealed that oral metronomic therapy markedly reduced microvessel density, proliferation and increased apoptosis in the tumor tissues. Oral metronomic doses were significantly correlated with the elevation of plasma deoxyuridine level, an essential biomarker for pemetrexed therapy. One-month toxicity study confirmed that daily dosing of oral pemetrexed is safe by investigating apoptosis in the gut tissues from mice. Moreover, we analyzed different biochemical parameters and enzymes from the blood to prove that our newly developed oral pemetrexed complex is well tolerated.

Self-Triggered Apoptosis Enzyme Prodrug Therapy (STAEPT): Enhancing Targeted Therapies via Recurrent Bystander Killing Effect by Exploiting Caspase-Cleavable Linker.

Tumor heterogeneity is associated with the therapeutic failures of targeted therapies. To overcome such heterogeneity, a novel targeted therapy is proposed that could kill tumor populations with diverse phenotypes by delivering nonselective cytotoxins to target-positive cells as well as to the surrounding tumor cells via a recurrent bystander killing effect. A representative prodrug is prepared that targets integrin αvß3 and releases cytotoxins upon entering cells or by caspase-3. This allows the prodrug to kill integrin αvß3-positive cells and upregulate caspase-3, which in turn, activates the prodrug to release a cytotoxin that could subsequently diffuse into and kill the neighboring tumor cells. Apoptotic cells further upregulate and release caspase-3, which activate more prodrugs leading to another round of adjacent cell death and caspase-3 release. Thus, the bystander killing effect could occur repeatedly, leading to augmented and widespread anticancer activity. This strategy provides an avenue that could advance the current targeted therapy.

Multiple nanoemulsion system for an oral combinational delivery of oxaliplatin and 5-fluorouracil: preparation and in vivo evaluation.

Oxaliplatin (OXA) is a third-generation cisplatin analog that has been approved as first-line chemotherapy in combination with 5-fluorouracil (5-FU) for the treatment of resectable and advanced colorectal cancer. However, the therapeutic efficacy of oral OXA and 5-FU is limited by their low bioavailability due to poor membrane permeability. The aim of the present study was to develop an oral delivery system for OXA and 5-FU. We constructed an ion-pairing complex of OXA with a deoxycholic acid derivative (Nα-deoxycholyl-l-lysyl-methylester, DCK) (OXA/DCK) as a permeation enhancer. Next, we prepared multiple water-in-oil-in-water nanoemulsions incorporating OXA/DCK and 5-FU to enhance their oral absorption. To evaluate their membrane permeability, we assessed in vitro permeabilities of OXA/DCK and 5-FU through an artificial intestinal membrane and Caco-2 cell monolayer. Finally, oral bioavailability in rats and tumor growth inhibition in the colorectal adenocarcinoma cell (CT26)-bearing mouse model were investigated after oral administration of nanoemulsion containing OXA/DCK and 5-FU. The droplet size of the optimized nanoemulsion was 20.3±0.22 nm with a zeta potential of -4.65±1.68 mV. In vitro permeabilities of OXA/DCK and 5-FU from the nanoemulsion through a Caco-2 cell monolayer were 4.80- and 4.30-fold greater than those of OXA and 5-FU, respectively. The oral absorption of OXA/DCK and 5-FU from the nanoemulsion also increased significantly, and the resulting oral bioavailability values of OXA/DCK and 5-FU in the nanoemulsive system were 9.19- and 1.39-fold higher than those of free OXA and 5-FU, respectively. Furthermore, tumor growth in CT26 tumor-bearing mice given the oral OXA/DCK- and 5-FU-loaded nanoemulsion was maximally inhibited by 73.9%, 48.5%, and 38.1%, compared with tumor volumes in the control group and the oral OXA and 5-FU groups, respectively. These findings demonstrate the therapeutic potential of a nanoemulsion incorporating OXA/DCK and 5-FU as an oral combination therapy for colorectal cancer.

Oral delivery of zoledronic acid by non-covalent conjugation with lysine-deoxycholic acid: In vitro characterization and in vivo anti-osteoporotic efficacy in ovariectomized rats.

We assessed the possibility of changing the route of administration of zoledronic acid to an oral dosage form and its therapeutic efficacy in an estrogen-deficient osteoporosis rat model. To enhance oral bioavailability, we formed an ionic complex by electrostatic conjugation of zoledronic acid with lysine-linked deoxycholic acid (Lys-DOCA, an oral absorption enhancer). After forming the complex, the characteristic crystalline features of pure zoledronic acid disappeared completely in the powder X-ray diffractogram and differential scanning calorimetry thermogram, indicating that zoledronic acid existed in an amorphous form in the complex. In vitro permeabilities of zoledronic acid/Lys-DOCA (1:1) (ZD1) and zoledronic acid/Lys-DOCA (1:2) (ZD2) complex across Caco-2 cell monolayers were 2.47- and 4.74-fold higher than that of zoledronic acid, respectively. Upon intra-jejunal administration to rats, the intestinal absorption of zoledronic acid was increased significantly and the resulting oral bioavailability of the ZD2 complex was determined to be 6.76±2.59% (0.548±0.161% for zoledronic acid). Ovariectomized (OVX) rats showed 122% increased bone mineral density versus the OVX control at 12weeks after treatment with once weekly oral administration of ZD2 complex (16µg/kg of zoledronic acid). Furthermore, rats treated with ZD2 complex orally showed significant improvement in the parameters of trabecular microarchitecture and bone strength: 149% higher bone volume fraction (BV/TV), 115% higher trabecular number (Tb.N), and 56% higher mean maximum load (Fmax) than in the OVX group. The trabecular microstructure and bone mechanical properties in the oral zoledronic acid group were not significantly changed compared with the OVX control. Thus, the oral ZD2 complex inhibited osteoporosis progression effectively by promoting osteogenesis and trabecular connectivity. The oral ZD2 complex would be expected to improve patient compliance by replacing the conventional injectable form and expand the indications, to include prophylaxis for osteoporosis and bone metastases.

Albumin-binding caspase-cleavable prodrug that is selectively activated in radiation exposed local tumor.

Existence of the genomically and epigenomically diverse subclones in a tumor severely limits the therapeutic efficacy of targeted agents. To overcome such a limitation, we prepared a novel targeted prodrug, EMC-DEVD-S-DOX, which comprises two important features: radiation-induced apoptosis targeting and albumin-binding properties. In particular, the prodrug binds circulating albumin after intravenous administration and then activated by caspase-3, which is upregulated from apoptotic cells that responded to radiotherapy. The prodrug was designed to bind circulating albumin to extend half-life and facilitate tumor accumulation in order to increase the possibility of contacting caspase-3, which is only transiently upregulated during apoptosis. Our results showed that EMC-DEVD-S-DOX had a prolonged half-life with enhanced tumor accumulation, which clearly benefited the therapeutic effect of the prodrug. Also, agreeing with the in vitro studies that showed ignorable cytotoxic effect in the absence of caspase-3, the prodrug was effective only when combined with radiotherapy without any noticeable systemic toxicity in vivo. Due to the highly selective action of EMC-DEVD-S-DOX independent to the complex genomic profiles of tumor, the prodrug would overcome the limitation of current targeted therapy and potentiate radiotherapy in the clinical oncology.

End-Site-Specific Conjugation of Enoxaparin and Tetradeoxycholic Acid Using Nonenzymatic Glycosylation for Oral Delivery.

Heparin and low molecular weight heparins (LMWHs) have been the drug of choice for the treatment or the prevention of thromboembolic disease. Different methods are employed to prepare the LMWHs that are clinically approved for the market currently. In particular, enoxaparin, which has a reducing sugar moiety at the end-site of polysaccharide, is prepared by alkaline depolymerization. Focusing on this end-site-specific activity of LMWHs, we conjugated the tetraoligomer of deoxycholic acid (TetraDOCA; TD) at the end-site of enoxaparin via nonenzymatic glycosylation reaction. The end-site-specific conjugation is important for polysaccharide drug development because of the heterogeneity of polysaccharides. This study also showed that orally active enoxaparin and tetraDOCA conjugate (EnoxaTD) had therapeutic effect on deep vein thrombosis (DVT) without bleeding in animal models. Considering the importance of end-specific conjugation, these results suggest that EnoxaTD could be a drug candidate for oral heparin development.

Enhanced oral absorption of ibandronate via complex formation with bile acid derivative.

Bisphosphonates are recommended for the treatment of postmenopausal osteoporosis, Paget's disease, bone metastasis, and multiple myeloma. However, the efficacy of oral preparations is limited because of their low bioavailabilities and adverse effects from the gastrointestinal tract. This study was conducted to investigate whether N(α)-deoxycholyl-L-lysyl-methylester (DCK), an absorption enhancer derived from deoxycholic acid, can increase the oral bioavailability of ibandronate. We prepared a physical complex of ibandronate with DCK, and evaluated its permeability across a parallel artificial membrane. Furthermore, pharmacokinetic profile and oral absorption of the optimized formulation were also studied in rats. DCK enhanced the apparent membrane permeability of ibandronate by 14.4-fold in a parallel artificial membrane permeability assay model, compared with when ibandronate was applied alone. When ibandronate-DCK complex was intrajejunally administered to rats, it resulted in a 2.8- and 4.3-fold increase in maximum plasma concentration and area under the concentration-time curve from time zero to the last measurable time point, respectively. These results demonstrate that the ibandronate-DCK formulation can improve the oral absorption of ibandronate, allowing less frequent dosing to avoid side effects as well to enhance patient compliance.

Multilayer nanoparticles for sustained delivery of exenatide to treat type 2 diabetes mellitus.

A method for the sustained delivery of exenatide was proposed using nanoparticles (NPs) with a core/shell structure. The interactions between lipid bilayers and Pluronics were utilized to form various NPs using a layer-by-layer approach. Transmittance electron microscopy and dynamic light scattering were used to examine the morphology of the NPs. The in vitro release pattern was observed as a function of changes in the structure of the NPs, and the structural integrity of exenatide released was examined by SDS-PAGE analysis. Pharmacokinetics and antidiabetic effects were also observed with the structural change of NPs using in vivo animal models. In vitro-in vivo correlation was discussed in relation to manipulation of the NP structures.