Nanomedicine and Drug Delivery Laboratory, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045, United States.
Mol Pharm. 2012 Nov 5;9(11):3136-46. doi: 10.1021/mp300245r. Epub 2012 Oct 11.
In this work, we aim to design and synthesize prodrugs of gatifloxacin targeting organic cation transporter (OCT), monocarboxylate transporter (MCT), and ATB (0, +) transporters and to identify a prodrug with enhanced delivery to the back of the eye. Dimethylamino-propyl, carboxy-propyl, and amino-propyl(2-methyl) derivatives of gatifloxacin (GFX), DMAP-GFX, CP-GFX, and APM-GFX, were designed and synthesized to target OCT, MCT, and ATB (0, +) transporters, respectively. An LC-MS method was developed to analyze drug and prodrug levels in various studies. Solubility and log D (pH 7.4) were measured for prodrugs and the parent drug. The permeability of the prodrugs was determined in the cornea, conjunctiva, and sclera-choroid-retinal pigment epitheluim (SCRPE) and compared with gatifloxacin using an Ussing chamber assembly. Permeability mechanisms were elucidated by determining the transport in the presence of transporter specific inhibitors. 1-Methyl-4-phenylpyridinium iodide (MPP+), nicotinic acid sodium salt, and α-methyl-DL-tryptophan were used to inhibit OCT, MCT, and ATB (0, +) transporters, respectively. A prodrug selected based on in vitro studies was administered as an eye drop to pigmented rabbits, and the delivery to various eye tissues including vitreous humor was compared with gatifloxacin dosing. DMAP-GFX exhibited 12.8-fold greater solubility than GFX. All prodrugs were more lipophilic, with the measured log D (pH 7.4) values ranging from 0.05 to 1.04, when compared to GFX (log D: -1.15). DMAP-GFX showed 1.4-, 1.8-, and 1.9-fold improvement in permeability across the cornea, conjunctiva, and SCRPE when compared to GFX. Moreover, it exhibited reduced permeability in the presence of MPP+ (competitive inhibitor of OCT), indicating OCT-mediated transport. CP-GFX showed 1.2-, 2.3-, and 2.5-fold improvement in permeability across the cornea, conjunctiva, and SCRPE, respectively. In the presence of nicotinic acid (competitive inhibitor of MCT), the permeability of CP-GFX was reduced across the conjunctiva. However, the cornea and SCRPE permeability of CP-GFX was not affected by nicotinic acid. APM-GFX did not show any improvement in permeability when compared to GFX across the cornea, conjunctiva, and SCRPE. Based on solubility and permeability, DMAP-GFX was selected for in vivo studies. DMAP-GFX showed 3.6- and 1.95-fold higher levels in vitreous humor and CRPE compared to that of GFX at 1 h after topical dosing. In vivo conversion of DMAP-GFX prodrug to GFX was quantified in tissues isolated at 1 h after dosing. The parent drug-to-prodrug ratio was 8, 70, 24, 21, 29, 13, 55, and 60% in the cornea, conjunctiva, iris-ciliary body, aqueous humor, sclera, CRPE, retina, and vitreous humor, respectively. In conclusion, DMAP-GFX prodrug enhanced solubility, log D, as well as OCT mediated delivery of gatifloxacin to the back of the eye.
在这项工作中,我们旨在设计和合成靶向有机阳离子转运体(OCT)、单羧酸转运体(MCT)和 ATB(0,+)转运体的加替沙星前药,并确定一种能够增强向眼后部递药的前药。设计并合成了加替沙星的二甲基氨基丙基、羧基丙基和氨基丙基(2-甲基)衍生物(GFX)、DMAP-GFX、CP-GFX 和 APM-GFX,分别靶向 OCT、MCT 和 ATB(0,+)转运体。开发了一种 LC-MS 方法来分析各种研究中的药物和前药水平。测量了前药和母体药物的溶解度和 log D(pH 7.4)。在角膜、结膜和巩膜脉络膜视网膜色素上皮(SCRPE)中测定了前药的渗透性,并与加替沙星使用 Ussing 室组件进行比较。通过确定在特定转运体抑制剂存在下的转运来阐明渗透性机制。1-甲基-4-苯基吡啶鎓碘化物(MPP+)、烟酸钠和α-甲基-DL-色氨酸分别用于抑制 OCT、MCT 和 ATB(0,+)转运体。根据体外研究选择的前药作为滴眼剂给药给色素沉着的兔子,并将其与加替沙星给药相比,比较向各种眼部组织(包括玻璃体)的递药情况。DMAP-GFX 的溶解度比 GFX 高 12.8 倍。与 GFX(log D:-1.15)相比,所有前药的脂溶性更高,测量的 log D(pH 7.4)值范围为 0.05 至 1.04。DMAP-GFX 与 GFX 相比,在角膜、结膜和 SCRPE 中的渗透性分别提高了 1.4、1.8 和 1.9 倍。此外,它在存在 MPP+(OCT 的竞争性抑制剂)时表现出降低的渗透性,表明存在 OCT 介导的转运。CP-GFX 在角膜、结膜和 SCRPE 中的渗透性分别提高了 1.2、2.3 和 2.5 倍。在烟酸钠(MCT 的竞争性抑制剂)存在下,CP-GFX 的结膜通透性降低。然而,CP-GFX 对角膜和 SCRPE 的通透性不受烟酸钠的影响。与 GFX 相比,APM-GFX 对角膜、结膜和 SCRPE 的渗透性没有任何改善。根据溶解度和渗透性,选择 DMAP-GFX 进行体内研究。与 GFX 相比,DMAP-GFX 在 1 小时后局部给药时在玻璃体和 CRPE 中的水平分别提高了 3.6 倍和 1.95 倍。在给药后 1 小时分离的组织中定量测定了 DMAP-GFX 前药向 GFX 的转化。母体药物与前药的比值分别为 8、70、24、21、29、13、55 和 60%,在角膜、结膜、虹膜睫状体、房水、巩膜、CRPE、视网膜和玻璃体中。总之,DMAP-GFX 前药增强了加替沙星向眼后部的递药,提高了溶解度、log D 以及 OCT 介导的递药。
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