Eye-drop formulations should hold as high a concentration of soluble drug in contact with ocular epithelium for as long as possible. However, eye tears and frequent blinking limit drug retention on the ocular surface, and gelling drops typically form clumps that blur vision. Here, we describe a gelling hypotonic solution containing a low concentration of a thermosensitive triblock copolymer for extended ocular drug delivery. On topical application, the hypotonic formulation forms a highly uniform and clear thin layer that conforms to the ocular surface and resists clearance from blinking, increasing the intraocular absorption of hydrophilic and hydrophobic drugs and extending the drug–ocular-epithelium contact time with respect to conventional thermosensitive gelling formulations and commercial eye drops. We also show that the conformal gel layer allows for therapeutically relevant drug delivery to the posterior segment of the eyeball in pigs. Our findings highlight the importance of formulations that conform to the ocular surface before viscosity enhancement for increased and prolonged ocular surface contact and drug absorption.

滴眼剂制剂应尽可能长时间地保持与眼上皮接触的高浓度可溶性药物。然而，眼泪和频繁眨眼会限制药物在眼表的滞留，而凝胶滴剂通常会形成模糊视力的团块。在这里，我们描述了一种凝胶低渗溶液，该溶液含有低浓度的热敏三嵌段共聚物，用于延长眼部药物递送。局部应用时，低渗制剂形成高度均匀和透明的薄层，与眼表一致，防止眨眼清除，增加亲水和疏水药物的眼内吸收，延长药物-眼-上皮的接触时间。热敏凝胶配方和商业眼药水。我们还表明，保形凝胶层允许将治疗相关的药物输送到猪眼球的后段。我们的研究结果强调了在粘度增强之前符合眼表的配方对于增加和延长眼表接触和药物吸收的重要性。