Design, Synthesis, and Therapeutic Evaluation of Poly(acrylic acid)–tetraDOCA Conjugate as a Bile Acid Transporter Inhibitor

Regulation of cholesterol and bile acid homeostasis has been attracting attention as a pharmaceutical target for the treatment of diseases, such as hypercholesterolaemia and type 2 diabetes. In recent years, small bile acid analogues have been developed for the purpose of apical sodium-dependent bile acid transporter (ASBT) inhibition. Here, we designed a novel hydrophilic ASBT inhibitor using oligomeric bile acid with a high affinity with ASBT. Polyacrylic acid–tetraDOCA conjugates (PATD) have the ability to bind to ASBT in order to induce hypocholesterolemic effects. Both the viability and the functionality of PATD were evaluated in vitro, showing that PATDs were effective in inhibiting the increases of cholesterol in the blood and oil in the liver induced by high fat diet (HFD). The results indicated that the newly developed biomaterials with oligomeric bile acids and a hydrophilic polymer are potent therapeutic agents for hyperlipidemia

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

Optimization of a Stable Linker Involved DEVD Peptide-Doxorubicin Conjugate That Is Activated upon Radiation-Induced Caspase-3-Mediated Apoptosis

The current study demonstrates the process of selecting an optimal structure for a caspase-3-cleavable doxorubicin prodrug that could be synthesized by simple chemistry in high yields. The prodrug was intended to activate in the presence of caspase-3, whose expression can be exogenously regulated by inducing apoptosis with radiation therapy at a specific site of interest. For this purpose, doxorubicin was conjugated with a DEVD peptide via a heterobifunctional linker. Since the active form of the prodrug comprises the linker besides doxorubicin, we tested several different linkers and selected EMCS based on the examination of its <i>in vitro</i> biological activities. Consequently, DEVD-cysteamide-EMCS-doxorubicin was synthesized as the final compound. According to the various <i>in vitro</i> and <i>in vivo</i> studies, the synthesized prodrug was highly selective for tumors when coupled with radiation therapy, with the added benefit of ease of production

Enhancement of the anticancer effect of atorvastatin-loaded nanoemulsions by improving oral absorption via multivalent intestinal transporter-targeting lipids

Atorvastatin (ATV) has attracted considerable attention as a potential therapeutic agent for cancer because it inhibits cancer cell proliferation by suppressing the mevalonate pathway. However, because of its low oral absorption, high doses of ATV are required for chemotherapeutic applications. In this study, we constructed ATV-loaded nanoemulsions (ATV-NEs) containing multivalent intestinal transporter-targeting lipids to improve the oral bioavailability of ATV. ATV-NEs were prepared via oil-in-water emulsification for transporter-targeted delivery, and contained the following anchors: an ionic complex of deoxycholic acid (DOCA) with the cationic lipid 1,2-dioleyl-3-trimethylammonium propane (DOTAP) (DOCA-DOTAP), a biotin-conjugated lipid (Biotinyl PE), and d-alpha-tocopherol polyethylene glycol succinate (TPGS) to allow bile acid- and multivitamin transporter-mediated permeation of ATV without P-glycoprotein (P-gp)-mediated efflux. The optimized formulation (ATV-NE#6) had 1,091% higher oral bioavailability than free ATV. Finally, treatment of 4T1 cell-bearing mice with oral ATV-NE#6 (equivalent to 40 mg/kg ATV) significantly suppressed tumor growth; the maximum tumor growth reduction was 2.44-fold that of the control group. The results thus suggest that ATV-NEs allow for effective oral chemotherapy by enhancing the oral bioavailability of ATV.</p

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

<p><b>Context:</b> As a class of angiogenesis inhibitors, heparin conjugates have shown significant effectiveness in several studies.</p> <p><b>Objectives:</b> 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.</p> <p><b>Methods:</b> 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.</p> <p><b>Results:</b> 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.</p> <p><b>Conclusions:</b> LHT7 (i.v. infusion) could be safely used for further clinical development as a multi-targeting anti-angiogenic agent.</p