Inhalable lactose-based dry powder formulations of low molecular weight heparin

Inhaled heparin: Past, present, and future

While heparin has traditionally served as a key anticoagulant in clinical practice for nearly a century, recent years have witnessed a growing interest in its role as a potent antiinflammatory and antiviral agent, as well as an anticancer agent. To address challenges with injection-based delivery, exploring patient-friendly routes such as oral and pulmonary delivery is crucial. This review specifically highlights the multiple therapeutic benefits of inhaled heparin. In summary, this review serves as a valuable source of information, providing deep insights into the diverse therapeutic advantages of inhaled heparin and its potential applications within clinical contexts.

An evolving perspective on novel modified release drug delivery systems for inhalational therapy

INTRODUCTION

Drugs delivered via the lungs are predominantly used to treat various respiratory disorders, including asthma, chronic obstructive pulmonary diseases, respiratory tract infections and lung cancers, and pulmonary vascular diseases such as pulmonary hypertension. To treat respiratory diseases, targeted, modified or controlled release inhalation formulations are desirable for improved patient compliance and superior therapeutic outcome.

AREAS COVERED

This review summarizes the important factors that have an impact on the inhalable modified release formulation approaches with a focus toward various formulation strategies, including dissolution rate-controlled systems, drug complexes, site-specific delivery, drug-polymer conjugates, and drug-polymer matrix systems, lipid matrix particles, nanosystems, and formulations that can bypass clearance via mucociliary system and alveolar macrophages.

EXPERT OPINION

Inhaled modified release formulations can potentially reduce dosing frequency by extending drug's residence time in the lungs. However, inhalable modified or controlled release drug delivery systems remain unexplored and underdeveloped from the commercialization perspective. This review paper addresses the current state-of-the-art of inhaled controlled release formulations, elaborates on the avenues for developing newer technologies for formulating various drugs with tailored release profiles after inhalational delivery and explains the challenges associated with translational feasibility of modified release inhalable formulations.

Pharmacology of Heparin and Related Drugs: An Update

Heparin has been used extensively as an antithrombotic and anticoagulant for close to 100 years. This anticoagulant activity is attributed mainly to the pentasaccharide sequence, which potentiates the inhibitory action of antithrombin, a major inhibitor of the coagulation cascade. More recently it has been elucidated that heparin exhibits anti-inflammatory effect via interference of the formation of neutrophil extracellular traps and this may also contribute to heparin's antithrombotic activity. This illustrates that heparin interacts with a broad range of biomolecules, exerting both anticoagulant and nonanticoagulant actions. Since our previous review, there has been an increased interest in these nonanticoagulant effects of heparin, with the beneficial role in patients infected with SARS2-coronavirus a highly topical example. This article provides an update on our previous review with more recent developments and observations made for these novel uses of heparin and an overview of the development status of heparin-based drugs. SIGNIFICANCE STATEMENT: This state-of-the-art review covers recent developments in the use of heparin and heparin-like materials as anticoagulant, now including immunothrombosis observations, and as nonanticoagulant including a role in the treatment of SARS-coronavirus and inflammatory conditions.

Preparation, Statistical Optimization and In-vitro Characterization of a Dry Powder Inhaler (DPI) Containing Solid Lipid Nanoparticles Encapsulating Amphotericin B: Ion Paired Complexes with Distearoyl Phosphatidylglycerol

The aim of this study was to prepare dry powder inhalers (DPIs) containing amphotericin B-loaded solid lipid nanoparticles (AMB-SLNs) as an alternative approach for prevention of pulmonary aspergillosis. For solubilizing AMB in small amounts of organic solvents ion paired complexes were firstly formed by establishing electrostatic interaction between AMB and distearoyl phosphatidylglycerol (DSPG). The SLN formulations containing AMB-DSPG complexes were prepared using glycerol monostearate (GMS) as the lipid matrix and soybean lecithin and tween 80 as the surfactants by solvent emulsification-evaporation technique. The nanoparticles were optimized through a fractional factorial design. DPIs were prepared by lyophilization technique using lactose as the inhalational carrier and then after, the formulations were evaluated in terms of aerodynamic particle size distribution using an Andersen cascade impactor. The morphology of the particles was examined using scanning electron microscopy (SEM) and in-vitro drug release profiles were evaluated. Following the statistical results, the particle size, Poly dispersity index (PdI), zeta potential, entrapment efficiency (EE%), and drug loading (DL%) of the optimized SLNs were 187.04 ± 11.97 nm, 0.188 ± 0.028, -30.16 ± 1.6 mV, 89.3 ± 3.47 % and 2.76 ± 0.32 %, respectively. Formulation containing 10% w/v of lactose with the calculated fine particle fraction value as 72.57 ± 4.33% exhibited the appropriate aerodynamic characteristics for pulmonary drug delivery. SEM images revealed de-agglomerated particles. In-vitro release studies showed sustained release of AMB from the carriers and the release kinetics were best fitted to the first order kinetic model.

Production and characterization of cellulose acetate - titanium dioxide nanotubes membrane fraxiparinized through polydopamine for clinical applications

The present paper introduces a study on the preparation and characterization of cellulose acetate - TiO₂ nanotubes membrane. In order to be used as a hemodialysis membrane, fraxiparinized nanotubes have been incorporated into the cellulose matrix. Fraxiparine embedding was performed via strong binding ability of dopamine. Composite membrane was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and water contact angle measurement. Electrochemical impedance spectroscopy was used to correlate the morphology of composite membrane with its electrochemical properties. Mott-Schottky test proved titanium dioxide semiconductor incorporation in composite membrane. Permeation test was made to determine pure water flux. The obtained results showed that addition of nanotubes had a positive impact on membrane permeation compared with a control polymeric membrane.

Rifampicin loaded chitosan nanoparticle dry powder presents an improved therapeutic approach for alveolar tuberculosis

Current treatment therapeutic approach for tuberculosis is the administration of first line drugs in the form of tablets and capsules for 4-6 months. However, this approach leads to severe adverse effects. Therefore, present study was designed to achieving local and sustained targeting of anti-tubercular drugs in order to reduce dose and frequency. The nanoparticle based dry powder formulation of rifampicin was developed and analyzed with respect to its direct targeting potential of lungs. Rifampicin loaded nanoparticles were formulated by ionic gelation probe sonication method, and characterized with respect to particle size, zeta potential, entrapment and drug loading efficiency. The range of size and entrapment efficiency of prepared nanoparticles was estimated from 124.1±0.2 to 402.3±2.8nm and 72.00±0.1%, respectively. The freeze-dried powder of nanoparticle formulation was used to carry out in vitro lung deposition studies through Andersen cascade impactor. The cumulative in vitro drug release studies with developed nanoparticle formulation showed sustained release up to 24h. Our in vitro sustained drug release results were corroborated by the extended residence and slow clearance of rifampicin from the lungs. Furthermore, our results suggest the minimum lung distribution of drug in treated rats which confirms the negligible toxicity rendered by nanoparticle dry powder formulation. Moreover, pharmacokinetic and toxicity studies carried out with prepared NPs dry powder inhalation (DPI) formulations and compared with conventional DPI.

Inhaled Heparin: Therapeutic Efficacy and Recent Formulations

Heparin is well known for its anticoagulant and anti-inflammatory properties. Inhaled heparin regimens are increasingly being used to manage lung disease. It has been used to treat cystic fibrosis, thromboembolism, and pulmonary fibrosis, as well as bronchial asthma and asthma-induced airway hypersensitivity. Several preclinical studies attained some useful effects of heparin-administered, parenterally and through inhalation, treatment of lung disease. Besides, recent clinical trials suggest that inhaled heparin for lung diseases is beneficial and safe, but such data remain to be limited. In 2005, the orphan designation was granted by the European Commission for heparin sodium (inhalation use) for the treatment of cystic fibrosis. The positive results of heparin in the pulmonary route necessitate a focus on the preparation and evaluation of heparin in advanced drug delivery systems, namely nano/microparticles and liposomes. Through this pulmonary delivery, heparin is protected from enzymatic degradation within the airway. Heparin is thus passively targeted into the lungs, and long-lasting localized treatment is achieved. On the other hand, these systems have encountered several problems as follows: (1) polymers, such as poly-L-lactide-glycolic acid, poly (lactic acid), and chitosan, used to prepare heparin-loaded microparticle/nanoparticle (MP/NP) systems have not been granted approval for lung application by the FDA and (2) liposomal and NP formulation stability is the main problem of formulation design. We propose that additional in vitro and in vivo research is necessary to assess the clinical applicability of this treatment strategy. The present article discusses heparin treatments for lung diseases and the use of heparin and/or heparin-loaded drugs in advanced delivery systems through the pulmonary route.

Pharmacology of Heparin and Related Drugs

Heparin has been recognized as a valuable anticoagulant and antithrombotic for several decades and is still widely used in clinical practice for a variety of indications. The anticoagulant activity of heparin is mainly attributable to the action of a specific pentasaccharide sequence that acts in concert with antithrombin, a plasma coagulation factor inhibitor. This observation has led to the development of synthetic heparin mimetics for clinical use. However, it is increasingly recognized that heparin has many other pharmacological properties, including but not limited to antiviral, anti-inflammatory, and antimetastatic actions. Many of these activities are independent of its anticoagulant activity, although the mechanisms of these other activities are currently less well defined. Nonetheless, heparin is being exploited for clinical uses beyond anticoagulation and developed for a wide range of clinical disorders. This article provides a "state of the art" review of our current understanding of the pharmacology of heparin and related drugs and an overview of the status of development of such drugs.

Aerosol Delivery of siRNA to the Lungs. Part 1: Rationale for Gene Delivery Systems

This article reviews the pulmonary route of administration, aerosol delivery devices, characterization of pulmonary drug delivery systems, and discusses the rationale for inhaled delivery of siRNA. Diseases with known protein malfunctions may be mitigated through the use of siRNA therapeutics. The inhalation route of administration provides local delivery of siRNA therapeutics for the treatment of various pulmonary diseases, however barriers to pulmonary delivery and intracellular delivery of siRNA exists. siRNA loaded nanocarriers can be used to overcome the barriers associated with the pulmonary route, such as anatomical barriers, mucociliary clearance, and alveolar macrophage clearance. Apart from naked siRNA aerosol delivery, previously studied siRNA carrier systems comprise of lipidic, polymeric, peptide, or inorganic origin. Such siRNA delivery systems formulated as aerosols can be successfully delivered via an inhaler or nebulizer to the pulmonary region. Preclinical animal investigations of inhaled siRNA therapeutics rely on intratracheal and intranasal siRNA and siRNA nanocarrier delivery. Aerosolized siRNA delivery systems may be characterized using in vitro techniques, such as dissolution test, inertial cascade impaction, delivered dose uniformity assay, laser diffraction, and laser Doppler velocimetry. The ex vivo techniques used to characterize pulmonary administered formulations include the isolated perfused lung model. In vivo techniques like gamma scintigraphy, 3D SPECT, PET, MRI, fluorescence imaging and pharmacokinetic/pharmacodynamics analysis may be used for evaluation of aerosolized siRNA delivery systems. The use of inhalable siRNA delivery systems encounters barriers to their delivery, however overcoming the barriers while formulating a safe and effective delivery system will offer unique advances to the field of inhaled medicine.

Heparin and related drugs: beyond anticoagulant activity

Heparin has been widely used as an anticoagulant for more than 80 years. However, there is now considerable evidence that heparin also possesses anti-inflammatory activity, both experimentally and clinically. Importantly in many instances, the anti-inflammatory actions of heparin are independent of anticoagulant activity raising the possibility of developing novel drugs based on heparin that retain the anti-inflammatory activity. Heparin exhibits anti-inflammatory activities via a variety of mechanisms including neutralization of cationic mediators, inhibition of adhesion molecules, and the inhibition of heparanase, all involved in leukocyte recruitment into tissues. It is anticipated that furthering our understanding of the anti-inflammatory actions of heparin will lead to the development of novel anti-inflammatory drugs for a variety of clinical indications.

In vitro, in vivo and ex vivo models for studying particle deposition and drug absorption of inhaled pharmaceuticals

Delivery of therapeutic agents via the pulmonary route has gained significant attention over the past few decades because this route of administration offers multiple advantages over traditional routes that include localized action, non-invasive nature and favorable lung-to-plasma ratio. However, assessment of post administration behavior of inhaled pharmaceuticals-such as deposition of particles over the respiratory airways, interaction with the respiratory fluid and movement across the air-blood barrier-is challenging because the lung is a very complex organs that is composed of airways with thousands of bifurcations with variable diameters. Thus, much effort has been put forward to develop models that mimic human lungs and allow evaluation of various pharmaceutical and physiological factors that influence the deposition and absorption profiles of inhaled formulations. In this review, we sought to discuss in vitro, in vivo and ex vivo models that have been extensively used to study the behaviors of airborne particles in the lungs and determine the absorption of drugs after pulmonary administration. We have provided a summary of lung cast models, cascade impactors, noninvasive imaging, intact animals, cell culture and isolated perfused lung models as tools to evaluate the distribution and absorption of inhaled particles. We have also outlined the limitations of currently used models and proposed future studies to enhance the reproducibility of these models.

Formulation of pH responsive peptides as inhalable dry powders for pulmonary delivery of nucleic acids

Nucleic acids have the potential to be used as therapies or vaccines for many different types of disease, but delivery remains the most significant challenge to their clinical adoption. pH responsive peptides containing either histidine or derivatives of 2,3-diaminopropionic acid (Dap) can mediate effective DNA transfection in lung epithelial cells with the latter remaining effective even in the presence of lung surfactant containing bronchoalveolar lavage fluid (BALF), making this class of peptides attractive candidates for delivering nucleic acids to lung tissues. To further assess the suitability of pH responsive peptides for pulmonary delivery by inhalation, dry powder formulations of pH responsive peptides and plasmid DNA, with mannitol as carrier, were produced by either spray drying (SD) or spray freeze drying (SFD). The properties of the two types of powders were characterised and compared using scanning electron microscopy (SEM), next generation impactor (NGI), gel retardation and in vitro transfection via a twin stage impinger (TSI) following aerosolisation by a dry powder inhaler (Osmohaler™). Although the aerodynamic performance and transfection efficacy of both powders were good, the overall performance revealed SD powders to have a number of advantages over SFD powders and are the more effective formulation with potential for efficient nucleic acid delivery through inhalation.

RNAi Therapeutic Platforms for Lung Diseases

RNA interference (RNAi) is rapidly becoming an important method for analyzing gene functions in many eukaryotes and holds promise for the development of therapeutic gene silencing. The induction of RNAi relies on small silencing RNAs, which affect specific messenger RNA (mRNA) degradation. Two types of small RNA molecules, i.e. small interfering RNAs (siRNAs) and microRNAs (miRNAs), are central to RNAi. Drug discovery studies and novel treatments of siRNAs are currently targeting a wide range of diseases, including various viral infections and cancers. Lung diseases in general are attractive targets for siRNA therapeutics because of their lethality and prevalence. In addition, the lung is anatomically accessible to therapeutic agents via the intrapulmonary route. Recently, increasing evidence indicates that miRNAs play an important role in lung abnormalities, such as inflammation and oncogenesis. Therefore, miRNAs are being targeted for therapeutic purposes. In this review, we present strategies for RNAi delivery and discuss the current state-of-the-art RNAi-based therapeutics for various lung diseases.

Comparative studies on chitosan and polylactic-co-glycolic acid incorporated nanoparticles of low molecular weight heparin

This study was performed to test the feasibility of chitosan and polylactic-co-glycolic acid (PLGA) incorporated nanoparticles as sustained-release carriers for the delivery of negatively charged low molecular weight heparin (LMWH). Fourier transform infrared (FTIR) spectrometry was used to evaluate the interactions between chitosan and LMWH. The shifts, intensity, and broadening of the characteristic peaks for the functional groups in the FTIR spectra indicated that strong interactions occur between the positively charged chitosans and the negatively charged LMWHs. Three types of LMWH nanoparticles (NP-1, NP-2, and NP-3) were prepared using chitosan with or without PLGA: NP-1 nanoparticles were formed by polyelectrolyte complexation after single mixing, NP-2 nanoparticles were prepared by polyelectrolyte complexation after single emulsion-diffusion-evaporation, and NP-3 nanoparticles were optimized by double emulsion-diffusion-evaporation. NP-3 nanoparticles of LMWH prepared by the emulsion-diffusion-evaporation method showed significant differences in particle morphology, size, zeta potential, and drug release profile compared to NP-1 nanoparticles formed by polyelectrolyte complexation. Another ionic complex of LMWH with chitosan-incorporated PLGA nanoparticles (NP-2) showed lower drug entrapment efficiency than that of NP-1 and NP-3. The drug release rate of NP-3 was slower than the release rates of NP-1 and NP-2, although particle morphology of NP-3 was similar to that of NP-2. Cell viability was not adversely affected when cells were treated with all three types of nanoparticles. The data presented in this study demonstrate that nanoparticles formulated with chitosan-PLGA could be a safe sustained-release carrier for the delivery of LMWH.

Strategies for non-invasive delivery of biologics

Macromolecular therapeutics, in particular, many biologics, is the most advancing category of drugs over conventional chemical drugs. The potency and specificity of the biologics for curing certain disease made them to be a leading compound in the pharmaceutical industry. However, due to their intrinsic nature, including high molecular weight, hydrophilicity and instability, they are difficult to be administered via non-invasive route. This is a major quest especially in biologics, as they are frequently used clinically for chronic disorders, which requires long-term administration. Therefore, many efforts have been made to develop formulation for non-invasive administration, in attempt to improve patient compliance and convenience. In this review, strategies for non-invasive delivery, in particular, oral, pulmonary and nasal delivery, that are recently adopted for delivery of biologics are discussed. Insulin, calcitonin and heparin were mainly focused for the discussion as they could represent protein, polypeptide and polysaccharide drugs, respectively. Many recent attempts for non-invasive delivery of biologics are compared to provide an insight of developing successful delivery system.

Pulmonary delivery of therapeutic siRNA

Small interfering RNA (siRNA) has a huge potential for the treatment or prevention of various lung diseases. Once the RNA molecules have successfully entered the target cells, they could inhibit the expression of specific gene sequence through RNA interference (RNAi) mechanism and generate therapeutic effects. The biggest obstacle to translating siRNA therapy from the laboratories into the clinics is delivery. An ideal delivery agent should protect the siRNA from enzymatic degradation, facilitate cellular uptake and promote endosomal escape inside the cells, with negligible toxicity. Lung targeting could be achieved by systemic delivery or pulmonary delivery. The latter route of administration could potentially enhance siRNA retention in the lungs and reduce systemic toxic effects. However the presence of mucus, the mucociliary clearance actions and the high degree branching of the airways present major barriers to targeted pulmonary delivery. The delivery systems need to be designed carefully in order to maximize the siRNA deposition to the diseased area of the airways. In most of the pulmonary siRNA therapy studies in vivo, siRNA was delivered either intratracheally or intranasally. Very limited work was done on the formulation of siRNA for inhalation which is believed to be the direction for future development. This review focuses on the latest development of pulmonary delivery of siRNA for the treatment of various lung diseases.

Non-anticoagulant effects of heparin: an overview

Heparin has long been known to possess biological effects that are unrelated to its anticoagulant activity. In particular, much emphasis has been placed upon heparin, or novel agents based upon the heparin template, as potential anti-inflammatory agents. Moreover, heparin has been reported to possess clinical benefit in humans, including in chronic inflammatory diseases and cancer, that are over and above the expected effects on blood coagulation and which in many cases are entirely separable from this role. This chapter aims to provide an overview of the non-anticoagulant effects that have been ascribed to heparin, from those involving the binding and inhibition of specific mediators involved in the inflammatory process to effects in whole system models of disease, with reference to the effects of heparin that have been reported to date in human diseases.