Liposomal Aerosols of Nitric Oxide (NO) Donor as a Long-Acting Substitute for the Ultra-Short-Acting Inhaled NO in the Treatment of PAH

Abstract

Purpose This study seeks to develop a liposomal formulation of diethylenetriamine NONOate (DN), a long acting nitric oxide (NO) donor, with a goal to replace inhaled NO (iNO) in the treatment of pulmonary arterial hypertension (PAH). Methods Liposomal formulations were prepared by a lipid film hydration method and modified with a cell penetrating peptide, CAR. The particles were characterized for size, polydispersity index (PDI), zeta potential, entrapment efficiency, storage and nebulization stability, and in-vitro release profiles. The cellular uptake and transport were assessed in rat alveolar macrophages (NR8383) and transforming growth factor β (TGF-β) activated rat pulmonary arterial smooth muscle cells (PASMCs). The fraction of the formulation that enters the systemic circulation, after intratracheal administration, was determined in an Isolated Perfused Rat Lung (IPRL) model. The safety of the formulations were assessed using an MTT assay and by measuring injury markers in the bronchoalveolar lavage (BAL) fluid; the pharmacological efficacy was evaluated by monitoring the changes in the mean pulmonary arterial (mPAP) and systemic pressure (mSAP) in a monocrotaline (MCT) induced-PAH rat model Results Liposome size, zeta potential, and entrapment efficiency were 171±4 nm, −37±3mV, and 46±5%, respectively. The liposomes released 70±5% of the drug in 8 h and were stable when stored at 4°C. CAR-conjugated-liposomes were taken up more efficiently by PASMCs than liposomes-without-CAR; the uptake of the formulations by rat alveolar macrophages was minimal. DN-liposomes did not increase lung weight, protein quantity, and levels of injury markers in the BAL fluid. Intratracheal CAR-liposomes reduced the entry of liposomes from the lung to blood; the formulations produced a 40% reduction in mPAP for 180 minutes. Conclusion This study establishes the proof-of-concept that peptide modified liposomal formulations of long-acting NO donor can be an alternative to short-acting iNO.

Electrophysiological characterization of the activating action of a novel liposomal nitric oxide carrier on Maxi-K channels in pulmonary artery smooth muscle cells

“…Here, using similar electrophysiological methodology, we report the synthesis and testing of biological activity in terms of Maxi-K activation of a novel liposomal NO carrier and donor termed Lip(NO). Our study contributes to the recent efforts in developing such drugs, for example efficient coencapsulation of NO with argon in liposomes containing phospholipids and cholesterol (Huang et al, 2009), as well as a A c c e p t e d M a n u s c r i p t liposomal aerosols formulation of NO donor diethylenetriamine NONOate developed for the treatment of pulmonary arterial hypertension have already been reported (Nahar et al, 2016).…”

Cocktail of Superoxide Dismutase and Fasudil Encapsulated in Targeted Liposomes Slows PAH Progression at a Reduced Dosing Frequency

“…38,43–45 The MCT rat model of PAH produces characteristic clinical features of PAH such as increased mPAP, right ventricular hypertrophy, pulmonary vascular remodeling, and diminished luminal circumference of small pulmonary arterioles. 41,46–48 Generally, healthy rats show an mPAP of ∼12–16 mmHg, which elevates to >25 mmHg in PAH rats.…”

Inhaled combination of sildenafil and rosiglitazone improves pulmonary hemodynamics, cardiac function, and arterial remodeling

“…To address the limitations of multiple dosing for inhaled anti-PAH drugs, we previously demonstrated that dosing interval can be extended and thus the dosing frequency for anti-PAH medications can be reduced by administering the drugs as inhalable sustained-release particulate formulations (16,18,39,40). We have shown that inhalable drug-laden particles, given either in the form of biodegradable polymeric particles or liposomes, can elicit pulmonary-specific effects of anti-PAH drugs at a reduced dosing frequency (15)(16)(17)40). The inhaled formulations of various anti-PAH drugs including prostaglandin E 1 , fasudil, long-acting nitric oxide donors, and superoxide dismutase, when formulated as polymeric or lipidic particles, can minimize drops in systemic arterial pressure by restricting the drugs' vasodilatory effects within the pulmonary vasculature.…”