Development of dry powder inhalation system of novel vasoactive intestinal peptide (VIP) analogue for pulmonary administration

The role of vasoactive intestinal peptide in pulmonary diseases

Vasoactive intestinal peptide (VIP) is an abundant neurotransmitter in the lungs and other organs. Its discovery dates back to 1970. And VIP gains attention again due to the potential application in COVID-19 after a research wave in the 1980s and 1990s. The diverse biological impacts of VIP extend beyond its usage in COVID-19 treatment, encompassing its involvement in various pulmonary and systemic disorders. This review centers on the function of VIP in various lung diseases, such as pulmonary arterial hypertension, chronic obstructive pulmonary disease, asthma, cystic fibrosis, acute lung injury/acute respiratory distress syndrome, pulmonary fibrosis, and lung tumors. This review also outlines two main limitations of VIP as a potential medication and gathers information on extended-release formulations and VIP analogues.

An Update on Advancements and Challenges in Inhalational Drug Delivery for Pulmonary Arterial Hypertension

A lethal condition at the arterial–alveolar juncture caused the exhaustive remodeling of pulmonary arterioles and persistent vasoconstriction, followed by a cumulative augmentation of resistance at the pulmonary vascular and, consequently, right-heart collapse. The selective dilation of the pulmonary endothelium and remodeled vasculature can be achieved by using targeted drug delivery in PAH. Although 12 therapeutics were approved by the FDA for PAH, because of traditional non-specific targeting, they suffered from inconsistent drug release. Despite available inhalation delivery platforms, drug particle deposition into the microenvironment of the pulmonary vasculature and the consequent efficacy of molecules are influenced by pathophysiological conditions, the characteristics of aerosolized mist, and formulations. Uncertainty exists in peripheral hemodynamics outside the pulmonary vasculature and extra-pulmonary side effects, which may be further exacerbated by underlying disease states. The speedy improvement of arterial pressure is possible via the inhalation route because it has direct access to pulmonary arterioles. Additionally, closed particle deposition and accumulation in diseased tissues benefit the restoration of remolded arterioles by reducing fallacious drug deposition in other organs. This review is designed to decipher the pathological changes that should be taken into account when targeting the underlying pulmonary endothelial vasculature, especially with regard to inhaled particle deposition in the alveolar vasculature and characteristic formulations.

Protective effects of poly (butyl) cyanoacrylate nanoparticles containing vasoactive intestinal peptide against 6-hydroxydopamine-induced neurotoxicity in vitro

The present study investigated brain delivery system of vasoactive intestinal peptide (VIP) adsorbed on poly (butyl cyanoacrylate) nanoparticles coated with polysorbate 80 (P80-poly (butyl) cyanoacrylate (PBCA)-nanoparticles (NPs)) and the neuroprotective effects on the formulation in the model of 6-hydroxydopamine (6-OHDA)-induced Parkinsonian dysfunction in the human neuroblastoma cell line SH-SY5Y. Drug-loaded nanoparticles were prepared by emulsion polymerization method using VIP and PBCA and then stirring with polysorbate 80. The resulting nanoparticles possessed high entrapment efficiency and favorable stability against CaCl2 or fetal bovine serum (FBS)-induced aggregation. Use of fluorescein isothiocyanate (FITC)-conjugated polysorbate 80-PBCA nanoparticles in confocal microscopy revealed that nanoparticles are located inside, while the FITC solution could not penetrate into the cells. The blank nanoparticles showed no significant effects on cell viability, indicating that they had no role in protection; however, polysorbate 80-modified VIP-loading PBCA nanoparticles showed enhanced cell viability compared to free VIP in 6-OHDA-mimic cellular model of Parkinson's disease. In addition, the nanoparticles strikingly increased the anti-apoptosis activity and restored the loss of mitochondrial membrane potential (MMP) significantly after the treatment of 6-OHDA. These results demonstrated that the activity of VIP was enhanced by polysorbate 80-PBCA nanoparticles compared to control solutions, suggesting that PBCA nanoparticles coated with polysorbate 80 could be an effective carrier system for VIP.

Comparative characterization of lung muscarinic receptor binding after intratracheal administration of tiotropium, ipratropium, and glycopyrrolate

The aim of the current study was to characterize comparatively the binding of muscarinic receptor in the lung of rats intratracheally administered anticholinergic agents (tiotropium, ipratropium, glycopyrrolate) used clinically to treat chronic obstructive pulmonary disease (COPD) and asthma. Binding parameters of [N-methyl-(3)H]scopolamine methyl chloride ([(3)H]NMS) were determined in tissues (lung, bladder, submaxillary gland) of rats intratracheally administered tiotropium, ipratropium, and glycopyrrolate. The in vitro binding affinity of tiotropium for the receptors was 10-11-fold higher than those of ipratropium and glycopyrrolate. Intratracheal administration of tiotropium (0.6-6.4 nmol/kg) caused sustained (lasting at least 24 h) increase in the apparent dissociation constant (K(d)) for [(3)H]NMS binding in rat lung compared with the control value. Concomitantly, there was a long-lasting decrease in the maximal number of binding sites (B(max)) for [(3)H]NMS. Similary, ipratropium and glycopyrrolate at 7.3 and 7.5 nmol/kg, respectively, brought about a significant increase in K(d) for [(3)H]NMS binding. The effect by ipratropium was observed at 2 h but not 12 h, and that by glycopyrrolate lasted for 24 h. Both agents had little influence on the muscarinic receptors in the bladder and submaxillary gland. The present study provides the first evidence that tiotropium, ipratropium, and glycopyrrolate administered intratracheally in rats selectively bound muscarinic receptors of the lung, and tiotropium and glycopyrrolate had a much longer-lasting effect than ipratropium.

Inhalable powder formulation of vasoactive intestinal peptide derivative, [R15,20,21, L17]-VIP-GRR, attenuated neutrophilic airway inflammation in cigarette smoke-exposed rats

Cigarette smoke (CS) has been identified as a predominant causative factor for chronic obstructive pulmonary disease (COPD), so CS-exposed rodent model of COPD has drawn considerable interest and attention for fundamental study and drug discovery. In the present study, using experimental COPD model rats, the therapeutic potential of a newly prepared respirable powder (RP) formulation of a long-acting VIP derivative, [Arg(15,20,21), Leu(17)]-VIP-GRR (IK312532), was assessed with a focus on pro-inflammatory biomarkers, morphological and histochemical changes, and infiltrated cells in the respiratory system. CS exposure of rats for 11 days led to the marked infiltration of inflammatory cells, except for eosinophils, in bronchiolar epithelium, followed by goblet cell metaplasia and hyperplasia. However, inhalation of IK312532-RP (50μg/rat) in the CS-exposed rats resulted in 74 and 71% reductions of granulocyte recruitment in bronchoalveolar lavage fluids and lung tissues, respectively, with 68% decrease of goblet cells. Biomarker study demonstrated that the inhaled IK312532-RP could suppress the CS-evoked increase of myeloperoxidase in both plasma and lung by 87 and 70%, respectively, possibly leading to potent suppression of neutrophilic inflammatory symptoms. The results from TUNEL staining were indicative of apoptotic damage in respiratory tissues of the CS-exposed rats, and there appeared to be marked decrease of TUNEL-positive cells in the CS-exposed rat with inhaled IK312532-RP. The present findings suggest that an inhalable formulation of IK312532 might be efficacious as a therapy for COPD or other airway inflammatory diseases because of its potent immunomodulating activities.

Inhalable powder formulation of a stabilized vasoactive intestinal peptide (VIP) derivative: anti-inflammatory effect in experimental asthmatic rats

Vasoactive intestinal peptide (VIP) exerts immunomodulating and anti-inflammatory activities through its specific receptors, such as VPAC1 and 2 receptors. Previously, a stabilized VIP derivative, [R(15,20,21), L(17)]-VIP-GRR (IK312532), was proposed as a candidate of anti-asthma drug, and a dry powder inhaler system of IK312532 was also developed for inhalation therapy with minimal systemic side-effects. In the present study, the anti-inflammatory properties of IK312532 respirable powder (RP) were characterized in an asthma/COPD-like animal model, with the use of newly developed ovalbumin (OVA)-RP for lung inflammation. Marked inflammatory events in the lung were observed after OVA-RP challenge in rats as evidenced by significant increase of inflammatory biomarkers such as eosinophil peroxidase (EPO), myeloperoxidase (MPO) and lactate dehydrogenase (LDH). However, intratracheal administration of IK312532-RP led to significant attenuation of plasma EPO, MPO and LDH activities, as well as significant reduction of recruited inflammatory cells in BALF, especially macrophages and eosinophils. In the rats pretreated with IK312532-RP, histochemical examinations revealed that the inflammatory cells infiltrating to the lung and the epithelial wall thickness decreased significantly by 85% and 58%, respectively. Thus, inhalable powder formulation of IK312532 exerts its anti-inflammatory activity by suppressing granulocyte recruitment to the lung and epithelial hyperplasia, followed by the reduction of cytotoxic peroxidases.

A hand-held apparatus for "nose-only" exposure of mice to inhalable microparticles as a dry powder inhalation targeting lung and airway macrophages

Microparticles containing isoniazid and rifabutin were aerosolised using a simple apparatus fabricated from a 15-ml centrifuge tube. The dose available for inhalation by rodents was determined by collecting microparticles emitted at the delivery port. The dose available for inhalation was proportional to durations of exposure ranging from 10 to 90 s (10.5-13.5 CV%) and the weight of powder taken for fluidization (10-50 mg, r2=0.982). The apparatus was then used to administer inhalations of microparticles to mice. Other groups of mice received free rifabutin orally, or by i.v. injection. Rifabutin was estimated in serum and tissues of dosed mice by HPLC. When approximately 20 mg of microparticles were loaded in the apparatus, approximately 2.5 mg were collected at the delivery port in 30 s of operation. Mice inhaled approximately 300 microg of the 2.5 mg emitted at the delivery port. Airway and lung macrophages of mice receiving inhalations for 30 s accumulated 0.38 microg of rifabutin, while the amount in blood serum of these mice was 0.62 microg. In mice receiving 83 microg rifabutin i.v. or orally, the intracellular amounts were 0.06 and 0.07 microg respectively, while the amounts in serum were 1.02 and 0.80 microg. These observations confirmed that inhalation of microparticles targeted airway and lung macrophages.

Bioactive analogues and drug delivery systems of vasoactive intestinal peptide (VIP) for the treatment of asthma/COPD

Vasoactive intestinal peptide (VIP) is one of the major peptide transmitters in the central and peripheral nervous systems, being involved in a wide range of biological functions. In an airway system where VIP-immunoreactive nerve fibers are present, VIP acts as neurotransmitter or neuromodulator of the inhibitory non-adrenergic and non-cholinergic airway nervous system and influences many aspects of pulmonary biology. A clinical application of VIP has been believed to offer potential benefits in the treatment of chronic inflammatory lung diseases such as asthma and chronic obstructive pulmonary disease (COPD), however, its clinical application has been limited in the past for a number of reasons, including its extremely short plasma half-life after intravenous administration and difficulty in administration routes. The development of long-acting VIP analogues, in combination with appropriate drug delivery systems, may provide clinically useful agents for the treatment of asthma/COPD. In this review, development of efficacious VIP derivatives, drug delivery systems designed for VIPs and the potential application for asthma/COPD are discussed. We also include original data from our chemical modification experiments and formulation studies, which led to successful development of [R(15, 20, 21), L(17)]-VIP-GRR (IK312532), a potent VIP analogue, and a VIPs-based dry powder inhaler system.