Semi-synthetic bile acids as novel drug candidate in liver diseases: physico-chemical characterization and HPLC-ES-MS/MS methods for their quali-quantitative analysis in different experimental animal models

The physico-chemical characterization, structure-pharmacokinetic and metabolism studies of new semi synthetic analogues of natural bile acids (BAs) drug candidates have been performed. Recent studies discovered a role of BAs as agonists of FXR and TGR5 receptor, thus opening new therapeutic target for the treatment of liver diseases or metabolic disorders. Up to twenty new semisynthetic analogues have been synthesized and studied in order to find promising novel drugs candidates. In order to define the BAs structure-activity relationship, their main physico-chemical properties (solubility, detergency, lipophilicity and affinity with serum albumin) have been measured with validated analytical methodologies. Their metabolism and biodistribution has been studied in “bile fistula rat”, model where each BA is acutely administered through duodenal and femoral infusion and bile collected at different time interval allowing to define the relationship between structure and intestinal absorption and hepatic uptake ,metabolism and systemic spill-over. One of the studied analogues, 6α-ethyl-3α7α-dihydroxy-5β-cholanic acid, analogue of CDCA (INT 747, Obeticholic Acid (OCA)), recently under approval for the treatment of cholestatic liver diseases, requires additional studies to ensure its safety and lack of toxicity when administered to patients with a strong liver impairment. For this purpose, CCl4 inhalation to rat causing hepatic decompensation (cirrhosis) animal model has been developed and used to define the difference of OCA biodistribution in respect to control animals trying to define whether peripheral tissues might be also exposed as a result of toxic plasma levels of OCA, evaluating also the endogenous BAs biodistribution. An accurate and sensitive HPLC-ES-MS/MS method is developed to identify and quantify all BAs in biological matrices (bile, plasma, urine, liver, kidney, intestinal content and tissue) for which a sample pretreatment have been optimized.

Determining the effect of regulation on Microfinance Institutions Financial Self-Sustainability. A Cross-Country Comparison

Microfinance is an initiative which seeks to address financial inclusion, micro-entrepreneurship, and poverty reduction without over burdening governments. However, the current sector of microfinance is still heavily dependent on the good will of donors. The over-reliance on donations is a feature which threatens the long term sustainability of microfinance. Much has been written about this reliance, but research to date hasn’t empirically examined the effect of regulation as a mediator. This is a critical area of study because regulation directly affects Microfinance Institutions’ (MFI) innovation, and innovation is what shapes the future of microfinance. This thesis considers the role that regulation plays in affecting MFI’s and their ability to innovate in products, services and long-term sustainability via access to capital. Interviews were undertaken with stakeholders in MFI’s, NGO’s, Self-Regulating Bodies, and Regulators in India, Pakistan, and Bangladesh. This thesis discusses findings from interviews in relation to regulatory measures regarding financial self-sustainability of MFI’s. The conclusions of this thesis have implications for policy and inform the microfinance literature.