The encapsulation of therapeutics into nanocarriers with specialized surface chemistries for targeting applications in the body is a major goal in the field of drug delivery. Here the encapsulation of an antitubercular peptide, ecumicin, into monodisperse nanocarriers 60 nm in diameter using a combination of Flash NanoPrecipitation and hydrophobic ion pairing is demonstrated. The lead formulation achieves 70% ecumicin encapsulation efficiency and 24% loading by mass. In vivo single‐dose oral (PO), subcutaneous (SC), and intraperitoneal (IP) pharmacokinetics (PK) are measured in mice, and the dose‐normalized area under the curve (AUC) of ecumicin nanocarriers dosed IP exceeded the dose‐normalized AUC of unencapsulated ecumicin dosed IP by a factor of 2.5. Next, variations of the lead formulation stabilized with a custom‐synthesized poly(caprolactone)‐ block ‐poly(ethylene glycol)‐hexamannose polymer at three levels of mannose surface coverage (0%, 4%, and 74% of polymer chains terminating in hexamannose) for targeting to macrophages are prepared. These formulations are evaluated against Mycobacterium tuberculosis in a macrophage culture at multiple concentrations and found to reduce colony‐forming units (CFU) counts by up to 3.8‐log 10 units, with greater antitubercular ecumicin activity measured from formulations prepared with higher amounts of surface mannose coverage. Taken together, these results suggest that Flash NanoPrecipitation with hydrophobic ion pairing is an effective method for encapsulating ionizable peptide therapeutics into macrophage‐targeted formulations for improved PK and targeted macrophage uptake in the body.

Autosomal dominant polycystic kidney disease (ADPKD) is a leading monogenetic cause of end-stage renal disease with limited therapeutic repertoire. A targeted drug delivery strategy that directs a small molecule to renal niches around cysts could increase the safety margins of agents that slow the progression of ADPKD but are poorly tolerated due to extrarenal toxicity. Herein, we determined whether previously characterized lysine-based and glutamic acid-based megalin-binding peptides can achieve renal-specific localization in the juvenile cystic kidney (JCK) mouse model of polycystic kidney disease and whether the distribution is altered compared with control mice. We performed in vivo optical and magnetic resonance imaging studies using peptides conjugated to the VivoTag 680 dye and demonstrated that megalin-interacting peptides distributed almost exclusively to the kidney cortex in both normal and JCK mice. Confocal analysis demonstrated that the peptide-dye conjugate distribution overlapped with megalin-positive renal proximal tubules. However, in the JCK mouse, the epithelium of renal cysts did not retain expression of the proximal tubule markers aquaporin 1 and megalin, and therefore these cysts did not retain peptide-dye conjugates. Furthermore, human kidney tumor tissues were evaluated by immunohistochemistry and revealed significant megalin expression in tissues from patients with renal cell carcinoma, raising the possibility that these tumors could be treated using this drug delivery strategy. Taken together, our data suggest that linking a small-molecule drug to these carrier peptides could represent a promising opportunity to develop a new platform for renal enrichment and targeting in the treatment of ADPKD and certain renal carcinomas.

Purpose.: Two noninvasive delivery strategies for VEGF/PDGF receptor tyrosine kinase inhibitors (RTKI) were explored that exploited uveal retention as a means for establishing an ocular drug depot: a single oral "loading" dose and topical administration. Methods.: Melanin binding was confirmed by centrifugation and mass spectrometry. Ocular retention was examined in pigmented and albino rats. Ocular release kinetics were measured 3 to 28 days postdosing in pigmented rats. Microautoradiography was used to demonstrate retention of RTKI in the uveal tract. A uveal drug depot of pazopanib was created by a single oral dose prior to induction of laser choroidal neovascularization (CNV). Choroid/retinal pigmented epithelium (RPE) retention of a related RTKI with enhanced topical bioavailability, GW771806, was confirmed by bioanalytics, and its ability to regress CNV compared with pazopanib. Results.: Pazopanib and GW771806 directly bound melanin and were retained within the uveal tract of pigmented rats for weeks following a single oral dose. Pazopanib was undetectable systemically following a single oral administration prior to CNV induction, and reduced CNV as well as twice daily dosing. Topical ocular delivery of GW771806 at 5 mg/mL led to high choroidal/RPE exposure and significantly regressed CNV lesions; 2 mg/mL prevented lesion progression. Conclusions.: Uveal retention of drugs such as pazopanib can be used to create a sustained-release depot. Topical GW771806 regressed CNV. These data indicate that topical or infrequent oral loading dose treatment with VEGF/PDGF RTKI retained in the choroid/RPE might allow noninvasive treatments for ocular neovascular disease.

A topical eye drop represents the least invasive method for targeting drugs to the back of the eye. Systemic exposure and potential toxicity are minimized relative to oral drugs, and an eye drop offers a more patient-friendly experience compared to intravitreal or periocular injections. Ocular tissue barriers and clearance mechanisms render this mode of delivery relatively inefficient for most drugs, and eye drop delivery for posterior indications pose a challenging proposition. However, there are presently a number of examples of compounds in clinical development for posterior diseases of the eye. This chapter will detail our mechanistic understanding of how these drugs transit to the back of the eye.

A series of biarylsulfonamides was identified as hCCR2 receptor antagonist but suffered from high plasma protein binding resulting in a >100 fold shift in activity in a functional GTPγS assay run in tandem in the presence and absence of human serum albumin. Introduction of an aryl amide with ethylenediamine linker led to compounds with reduced shifts and improved activity in whole blood.

The liver X receptors (LXR) play a key role in cholesterol homeostasis and lipid metabolism. SAR studies around tertiary-amine lead molecule 2, an LXR full agonist, revealed that steric and conformational changes to the acetic acid and propanolamine groups produce dramatic effects on agonist efficacy and potency. The new analogs possess good functional activity, demonstrating the ability to upregulate LXR target genes, as well as promote cholesterol efflux in macrophages.

Endothelial lipase (EL) activity has been implicated in HDL catabolism, vascular inflammation, and atherogenesis, and inhibitors are therefore expected to be useful for the treatment of cardiovascular disease. Sulfonylfuran urea 1 was identified in a high-throughput screening campaign as a potent and non-selective EL inhibitor. A lead optimization effort was undertaken to improve potency and selectivity, and modifications leading to improved LPL selectivity were identified. Radiolabeling studies were undertaken to establish the mechanism of action for these inhibitors, which were ultimately demonstrated to be irreversible inhibitors.

Recent studies using known Rho-associated kinase isoform 1 (ROCK1) inhibitors along with cellular and molecular biology data have revealed a pivotal role of this enzyme in many aspects of cardiovascular function. Here we report a series of ROCK1 inhibitors which were originally derived from a dihydropyrimidinone core 1. Our efforts focused on the optimization of dihydropyrimidine 2, which resulted in the identification of a series of dihydropyrimidines with improved pharmacokinetics and P450 properties.

The discovery, proposed binding mode, and optimization of a novel class of Rho-kinase inhibitors are presented. Appropriate substitution on the 6-position of the azabenzimidazole core provided subnanomolar enzyme potency in vitro while dramatically improving selectivity over a panel of other kinases. Pharmacokinetic data was obtained for the most potent and selective examples and one (6n) has been shown to lower blood pressure in a rat model of hypertension.

Rho kinase (ROCK1) mediates vascular smooth muscle contraction and is a potential target for the treatment of hypertension and related disorders. Indazole amide 3 was identified as a potent and selective ROCK1 inhibitor but possessed poor oral bioavailability. Optimization of this lead resulted in the discovery of a series of dihydropyridones, exemplified by 13, with improved pharmacokinetic parameters relative to the initial lead. Indazole substitution played a critical role in decreasing clearance and improving oral bioavailability.

Increased Rho kinase (ROCK) activity contributes to smooth muscle contraction and regulates blood pressure homeostasis. We hypothesized that potent and selective ROCK inhibitors with novel structural motifs would help elucidate the functional role of ROCK and further explore the therapeutic potential of ROCK inhibition for hypertension. In this article, we characterized two aminofurazan-based inhibitors, GSK269962A [N-(3-{[2-(4-amino-1,2,5-oxadiazol-3-yl)-1-ethyl-1H-imidazo[4, 5-c]pyridin-6-yl]oxy}phenyl)-4-{[2-(4-morpholinyl)ethyl]-oxy}benzamide] and SB-7720770-B [4-(7-{[(3S)-3-amino-1-pyrrolidinyl]carbonyl}-1-ethyl-1H-imidazo[4,5-c]pyridin-2-yl)-1,2,5-oxadiazol-3-amine], as members of a novel class of compounds that potently inhibit ROCK enzymatic activity. GSK269962A and SB-772077-B have IC50 values of 1.6 and 5.6 nM toward recombinant human ROCK1, respectively. GSK269962A also exhibited more than 30-fold selectivity against a panel of serine/threonine kinases. In lipopolysaccharide-stimulated monocytes, these inhibitors blocked the generation of inflammatory cytokines, such as interleukin-6 and tumor necrosis factor-alpha. Furthermore, both SB-772077-B and GSK269962A induced vasorelaxation in preconstricted rat aorta with an IC50 of 39 and 35 nM, respectively. Oral administration of either GSK269962A or SB-772077-B produced a profound dose-dependent reduction of systemic blood pressure in spontaneously hypertensive rats. At doses of 1, 3, and 30 mg/kg, both compounds induced a reduction in blood pressure of approximately 10, 20, and 50 mm Hg. In addition, administration of SB-772077-B also dramatically lowered blood pressure in DOCA salt-induced hypertensive rats. SB-772077-B and GSK269962A represent a novel class of ROCK inhibitors that have profound effects in the vasculature and may enable us to further evaluate the potential beneficial effects of ROCK inhibition in animal models of cardiovascular as well as other chronic diseases.

Rho Kinase I (ROCK I) is a serine/threonine kinase that is involved in diverse cellular signaling. To further understand the physiological role of ROCK I and to identify and develop potent and selective inhibitors of ROCK I, we have overexpressed and purified a constitutively active dimeric human ROCK I (3-543) kinase domain using the Sf9-baculovirus expression system. In addition, using a limited proteolysis technique, we have identified a minimal functional subdomain of ROCK I that can be used in crystallization studies. The availability of multimilligram amounts of purified and well characterized functional human ROCK I kinase domains will be useful in screening and structural studies.