The Early Preclinical Development Program for Locally Administered Investigational Medicinal Products in Ophthalmology: Preclinical Data Required for Starting a First-in-Human Clinical Trial in Europe-Basic Considerations and 2 Case Studies.

BACKGROUND: Although regulatory guidance defines which preclinical data are required in general before proceeding to first-in-human clinical trials, a certain level of flexibility exists in the actual planning, timing, and design of a drug development program. Developing an ophthalmic medicinal product adds additional challenges, since the eye is a complex organ with unique features and specialized ophthalmic guidance documents are sparse. METHODS: We analyzed the preclinical guidelines with a focus on European Union legislation and guidance documents provided by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). We elaborated the particularities specific to ophthalmic drug developments and deduced the preclinical knowledge needed to safely enter a first-in-human trial program. Two hypothetical medicinal products for ophthalmic indications were chosen and specificities for ophthalmic preclinical tests were elaborated. RESULTS AND CONCLUSION: We conclude that the preclinical program of ophthalmic medicines is flexible and differs, based on the intended use and the nature of the active substance.

Human duodenal proteome modulations by glutamine and antioxidants.

PURPOSE: Glutamine (Gln) has protective, anti-inflammatory effects in animal models and humans. Antioxidant nutrients may exert synergistic effects on intestinal functions. Therefore, these combined nutrients may have a therapeutic potential during intestinal inflammation. This study was designed to investigate in humans the effects of a supplement composed of Gln and high-dosed antioxidant micronutrients compared to isomolar Gln only, on duodenal proteome. EXPERIMENTAL DESIGN: Enteral perfusion of Gln (0.8 mmol x kg(-1) x h(-1)) or supplement was performed in two groups of six healthy volunteers during 5 h before taking endoscopic duodenal biopsies. Protein expression was analyzed by 2-DE and the relevant proteins identified by MS/MS. RESULTS: About 1500 protein spots were revealed in both supplement and Gln conditions. Comparative proteomics analysis indicated that 11 proteins were differentially and significantly (p≤0.05) expressed in response to the supplement. These proteins were essentially implicated in metabolism pathways, e.g. fatty acid binding protein-1 and 40S ribosomal protein SA expressions were downregulated while manganese superoxide dismutase and retinal dehydrogenase-1 expressions were upregulated. CONCLUSIONS AND CLINICAL RELEVANCE: This study provides new information on human duodenal proteome and its nutritional modulation, and supports further clinical investigations designed to evaluate the effects of Gln plus antioxidants during intestinal inflammation and cancer.

Partitioning of halofantrine hydrochloride between water, micellar solutions, and soybean oil: Effects on its apparent ionization constant.

Recent studies in a conscious dog model demonstrated intestinal lymphatic transport to be a significant contributor to the bioavailability of the highly lipid-soluble free-base of halofantrine (Hf), and surprisingly, also the poorly lipid-soluble hydrochloride salt (Hf. HCl). Partial conversion of solubilized Hf. HCl to Hf base within the intestinal lumen prior to the lymphatic uptake seemed to be the most likely explanation for these results. This hypothesis was supported by studies exploring the partitioning behavior of Hf. HCl between soybean oil (SBO) and aqueous micellar solutions containing different ionic and nonionic surfactants. Mixed micelles prepared from sodium taurodeoxycholate (NaTC) and lecithin (PC) were chosen to represent fed-state intestinal fluids. The apparent ionization constants derived from the partitioning versus pH profiles showed marked shifts when compared with the likely aqueous pK(a) value. In the present paper, the apparent pK(a) values of Hf in aqueous micellar phases, without a coexisting oil phase, were investigated to further probe the mechanisms underlying the effect of micellar media on the apparent ionization equilibrium, and subsequently, on its partitioning behavior in the triphasic systems. Another aim of this study was to further evaluate the aqueous pK(a) value of Hf. The results indicate that the aqueous pK(a) of Hf is most probably in the range approximately 8-9, and that the ionization equilibrium is highly dependent on the solution environment. For example, marked pK(a) shifts of several units were observed for Hf in the presence of different micellar species and SBO. The apparent ionization equilibrium depends not only on interaction of Hf with the micelles, but also on its partitioning into the oil phase.