Capillary Video-Microscopy on the Release of Water-Soluble Drugs from Double-Emulsion Globules into Giant Liposomes

摘要：0075712K。帕帕多普洛斯杜兰大学这是一项探索性拨款，其假设是毛细管视频显微镜可以唯一地揭示双乳小球中水溶性药物的释放机制以及它们向邻近的模仿生物细胞的巨型脂质体的传输机制的关键方面。目的在于阐明控制这些机制的现象以及对这些现象的控制将最终决定可溶性乳剂作为药物释放系统的成功应用。盐酸麻黄碱(EPH HCI)将作为模型水溶性药物，被包裹在W1/0/W2微球的W1隔室中，油膜将是石蜡油。油溶的非离子表面活性剂Span-80(山梨醇单油酸酯)和水溶性的非离子表面活性剂吐温-80将作为微球稳定性和药物释放的因素进行研究。双乳小球中的渗透压梯度将通过NaCl2调节。微毛细管(~200um i.d.，10200um)将由熔点管(1.1-1.2 mm i.d.)制成。X 100 mm)，使用Narishige PB-7型微吸管拉出器将其从中间拉出(见图2)。尖端细小的注射和微操作吸管将通过拉动微管(Microcapes)成形。直径0.688毫米X 78 mm)，以产生外径为10-15微米的尖端。未来的微吸管将被制成一个微谷(Narishige MF-9，见图3)，这样我们就可以抛光吸管的末端或将其弯曲成所需的形状。为了制备W1/0/W2球体，首先将微毛细管装入纯水或生理盐水中。然后插入一根装满油(含有油溶表面活性剂)的微吸管，并注入一大滴油滴。随后，内部的麻黄碱盐酸盐溶液液滴将通过与产生油滴的相同程序形成到油中。这种微球制备过程会导致W1和W2相之间的渗透压梯度，这将导致水溶性药物的释放。每个实验中将使用一个球体，并将在显微镜下观察该球体中的完整传输过程。在那些将监测环氧氯丙烷转移到容器中的实验中，首先将用1-palmitoyl-2oleoyl-sn-glycero-3-phosphocholine通过电铸法制备一个巨大的囊泡。通过在W1和W2中使用不同的盐度以及在W1中使用不同的EOPH HCI浓度，我们将知道在它们的条件下，水溶性是通过“膨胀-破裂”的机制输送的。破裂前所需的时间将被用作药物释放速率的衡量标准。影响破裂时间的一个明显的几何因素是W1液滴的大小。由于较小的W1液滴需要更长的时间才能破裂，因此这种液滴中的多分散性应该会导致长时间的释放，因此将被研究作为一种控制释放的工具。在那些不会产生膨胀和破裂的盐度条件下，水将通过一些促进扩散的机制从W1和W2传输，如反胶束化、自发乳化、水合表面活性剂或片层促进传输。我们将确定不同的表面活性剂组合和配方对药物释放的动力学影响，这些组合和配方在不同的条件下有利于某些机制。为了直观地显示释放的物质从W1/0/W2球体到邻近的巨大囊泡的运输，将水性荧光染料(N-甲基羟基喹啉碘化物)添加到盐酸麻黄碱溶液中。为了模拟可能在体内释放的情况，将研究接触和非接触的双重乳化球和巨大囊泡的构型。为了研究微球-囊泡接触下的药物传输，将巨大的微囊轻轻地推入，以直观地接触到W1/0/W2微球。

ABSTRACTCTS-0075712K. PapadopoulosTulane UniversityThis is an exploratory grant for which the hypotheses is that Capillary Video-microscopy can uniquely reveal key aspects of the release mechanisms of water-soluble drugs from double-emulsion globules and their transport into neighboring giant liposomes that mimic biological cells. The goal is to elucidate the phenomena which govern these mechanisms and the control of which will ultimately decide the successful application of soluble emulsions as drug-delivery systems.Ephedrine hydrochloride (EPH HCI) will be used as the model water-soluble drug, encapsulated in the W1 compartment of a W1/0/W2 globule, and the oil membrane will be paraffin oil. Oil-soluble, nonionic surfactant Span-80 (sorbitan monooleate) and water-soluble, non-ionic surfactant Tween-80 will be studied as factors of both globule stability and drug release. The osmotic pressure gradients in the double-emulsion globules will be adjusted through NaCl.Microcapillaries (~200 um i.d., 10 200 um) will be fabricated from melting point tubes (1.1-1.2 mm i.d. x 100 mm) by pulling them in the middle using a Narishige PB-7 micropipette puller (see Picture 2). Injection and micromanipulation pipettes with fine tip will be shaped by pulling microtubes (Microcapes. 0.688 mm i.d. X 78 mm) from one of their ends so as to produce a tip of outside diameter 10-15 um. Micropipettes will be future fashioned with a microgorge (Narishige MF-9, see picture 3), thus allowing us to polish the end of the pipette or to bend it to a desired shape.To prepare a W1/0/W2 globule, a microcapillary will be filled with pure water or a saline solution at first. A micropipette filled with oil (containing oil-soluble surfactants) will then be inserted and will inject a large oil drop. Subsequently, and internal ephedrine-hydrochloride-solution droplet will be formed into the oil via the same procedure as the one that produces the oil drop. This globule preparation procedure will lead to an osmotic pressure gradient between W1 and W2 phases, which will cause the release of the water-soluble drug. A single globule will be used in each experiment and the complete transport process in this globule will be observed microscopically. In those experiments that will monitor the transfer of EPH HCI to a vessel, a giant vesicle will first be prepared with 1-palmitoyl-2oleoyl-sn-glycero-3-phosphocholine through electroformation.By using different salinities in W1 and W2 and EOPH HCI concentrations in W1 we will know under their conditions the water-soluble is delivered by a "swelling-breakdown" mechanism. The time needed before rupture will be used as a measure of the drug release rate. An obvious geometrical factor that will effect the time of rupture is the size of the W1 droplets. Since smaller W1 droplets will take longer to burst, polydisperity in such droplets should lead to prolonged release, and thus will be studied as a tool to control delivery.Under those salinity conditions that will not produce swelling and breakdown, water will transport from W1 and W2 via some diffusion-facilitating mechanisms, such as reverse micellization, spontaneous emulsification, hydrated-surfactant or lamellar-facilitated transport. We will determine the kinetics of such drug release as effected by various surfactant combinations and formulations that will favor certain mechanisms over others under different conditions.To visualize the transport of the released material from the W1/0/W2 globule to the neighboring giant vesicle, aqueous fluorescent dye (N-Methylhdroxy-quinolinium iodide) will be added to ephedrine hydrochloride solution. In order to simulate possible release situations in the body, both contact and non-contact a configuration of a double-emulsion globule and a giant vesicle will be studied. To study drug transfer under globule-vesicle contact, the giant vesicle will be pushed gently so as to visually touch the W1/0/W2 globule.