Development of respirable rifampicin-loaded nano-lipomer composites by microemulsion-spray drying for pulmonary delivery

Recent Updates in Inhalable Drug Delivery System against Various Pulmonary Diseases: Challenges and Future Perspectives

In the current scenario, pulmonary disease has become a prime burden for morbidity and mortality alongside tremendous social and economic crises throughout the world. Numerous conventional drug delivery system and treatment approach targeting the respiratory region has been driven out. However, effective and accurate recovery has not been achieved yet. In this regard, nanotechnological- based inhalable drug delivery strategy including polymeric, lipidic, or metallic-based respirable microparticles plays an indispensable role in circumventing numerous challenges faced during traditional treatment. Excellent aerodynamic performance leads to enhanced lung targetability, reduced dosing frequency and hence systemic toxicities, as well as improved pharmaceutical attributes, and therefore pharmacokinetic profiles are interminable factors associated with nanotechnologicalbased inhalable delivery. In this review, we comprehensively explored recent advancements in nanotechnologically engineered inhalable formulations targeting each of the mentioned pulmonary diseases. Moreover, we systematically discussed possible respiratory or systemic toxicities about the indeterminate and undefined physicochemical characteristics of inhaled particles.

Review of inhalable nanoparticles for the pulmonary delivery of anti-tuberculosis drugs

Tuberculosis is an airborne disease caused by the pathogen, Mycobacterium tuberculosis, which predominantly affects the lungs. World Health Organization (WHO) has reported that about 85% of TB patients are cured with the existing 6-month antibiotic regimen. However, the lengthy oral administration of high-dose anti-TB drugs is associated with significant side effects and leads to drug resistance cases. Alternatively, reformulating existing anti-tubercular drugs into inhalable nanoparticulate systems is a promising strategy to overcome the challenges associated with oral treatment as they could enhance drug retention in the pulmonary region to achieve an optimal drug concentration in the infected lungs. Hence, this review provides an overview of the literature on inhalable nano-formulations for the delivery of anti-TB drugs, including their formulation techniques and preclinical evaluations between the years 2000 and 2020, gathered from electronic journals via online search engines such as Google Scholar and PubMed. Previous in vitro and in vivo studies highlighted that the nano-size, low toxicity, and high efficacy were among the factors influencing the fate of nanoparticulate system upon deposition in the lungs. Although many preclinical studies have shown that inhalable nanoparticles increased therapeutic efficacy and minimised adverse drug reactions when delivered through the pulmonary route, none of them has progressed into clinical trials to date. This could be attributed to the high cost of inhaled regimes due to the expensive production and characterisation of the nanoparticles as well as the need for an inhalation device as compared to the oral treatment. Another barrier could be the lack of medical acceptance due to insufficient number of trained staff to educate the patients on the correct usage of the inhalation device. Hence, these barriers should be addressed satisfactorily to make the inhaled nanoparticles regimen a reality for the treatment of TB.

Current Therapeutic Delivery Approaches Using Nanocarriers for the Treatment of Tuberculosis Disease

Tuberculosis is a major health issue globally and a leading cause of death due to the infective microorganism Mycobacterium tuberculosis. Treatment of drug resistance tuberculosis requires longer treatment with multiple daily doses of drugs. Unfortunately, these drugs are often associated with poor patient compliance. In this situation, a need has been felt for the less toxic, shorter, and more effective treatment of the infected tuberculosis patients. Current research to develop novel anti-tubercular drugs shows hope for better management of the disease. Research on drug targeting and precise delivery of the old anti-tubercular drugs with the help of nanotechnology is promising for effective treatment. This review has discussed the status currently available treatments for tuberculosis patients infected with Mycobacterium alone or in comorbid conditions like diabetes, HIV and cancer. This review also highlighted the challenges in the current treatment and research on the novel anti-tubercular drugs to prevent multi-drug-resistant tuberculosis. It presents the research highlights on the targeted delivery of anti-tubercular drugs using different nanocarriers for preventing multi-drug resistant tuberculosis. Report has shown the importance and development of the research on nanocarriers mediated anti-tubercular delivery of the drugs to overcome the current challenges in tuberculosis treatment.

pH-responsive microparticles of rifampicin for augmented intramacrophage uptake and enhanced antitubercular efficacy

In this study we present pH-responsive rifampicin (RIF) microparticles comprising lecithin and a biodegradable hydrophobic polymer, polyethylene sebacate (PES), to achieve high intramacrophage delivery and enhanced antitubercular efficacy. PES and PES-lecithin combination microparticles (PL MPs) prepared by single step precipitation revealed average size of 1.5 to 2.7 µm, entrapment efficiency ∼ 60 %, drug loading 12-15 % and negative zeta potential. Increase in lecithin concentration enhanced hydrophilicity. PES MPs demonstrated faster release in simulated lung fluid pH 7.4, while lecithin MPs facilitated faster and concentration dependent release in acidic artificial lysosomal fluid (ALF) pH 4.5 due to swelling and destabilization confirmed by TEM. PES and PL (1:2) MPs exhibited comparable macrophage uptake which was ∼ 5-fold superior than free RIF, in the RAW 264.7 macrophage cells. Confocal microscopy depicted intensified accumulation of the MPs in the lysosomal compartment, with augmented release of coumarin dye from the PL MPs, confirming pH-triggered increased intracellular release. Although, PES MPs and PL (1:2) MPs displayed comparable and high macrophage uptake, antitubercular efficacy against macrophage internalised M. tuberculosis was significantly higher with PL (1:2) MPs. This suggested great promise of the pH-sensitive PL (1:2) MPs for enhanced antitubercular efficacy.

Nano-Hydroxyapatite Composite Scaffolds Loaded with Bioactive Factors and Drugs for Bone Tissue Engineering

Nano-hydroxyapatite (n-HAp) is similar to human bone mineral in structure and biochemistry and is, therefore, widely used as bone biomaterial and a drug carrier. Further, n-HAp composite scaffolds have a great potential role in bone regeneration. Loading bioactive factors and drugs onto n-HAp composites has emerged as a promising strategy for bone defect repair in bone tissue engineering. With local delivery of bioactive agents and drugs, biological materials may be provided with the biological activity they lack to improve bone regeneration. This review summarizes classification of n-HAp composites, application of n-HAp composite scaffolds loaded with bioactive factors and drugs in bone tissue engineering and the drug loading methods of n-HAp composite scaffolds, and the research direction of n-HAp composite scaffolds in the future is prospected.

Nano Spray-Dried Drugs for Oral Administration: A Review

Spray drying is an important technology that is fast, simple, reproducible, and scalable. It has a wide application range, that is, in food, chemicals, and encapsulation of pharmaceuticals. The technology can be divided into conventional spray drying and nano spray drying. The key advantage of nano spray drying is the production of drug-loaded nanosized particles for various drug delivery applications. The recent developments in nano spray dryer technology and the market launch of the Nano Spray Dryer B-90 by Büchi Labortechnik AG in 2009 enabled the production of submicron spray-dried particles. This review focuses on nanosized drug delivery systems intended for oral administration produced by nano spray drying. First, the nano spray drying concept, the basic technologies implemented in the equipment, and the effects of the various process parameters on the final dry submicron powder properties are presented. Then, the topics of new formulation strategies of oral drugs are highlighted with examples that have entered the research literature in recent years. Next, the subjects of direct conversion of poorly water-soluble drugs, encapsulation of drugs, and drying of preformed nanoparticles are considered. Finally, topics such as morphology, particle size, size distribution, surface analysis, bioavailability, drug release, release kinetics, and solid-state characterization (by differential scanning calorimetry, X-ray diffraction, Fourier transform infrared spectroscopy, nuclear magnetic resonance) of oral drug delivery systems produced by nano spray drying are discussed. The review attempts to provide a comprehensive knowledge base with current literature and foresight to researchers working in the field of pharmaceutical technology and nanotechnology and especially in the field of nano spray drying.

Nano-based anti-tubercular drug delivery: an emerging paradigm for improved therapeutic intervention

Tuberculosis (TB) classified as one of the most fatal contagious diseases is of prime concern globally. Mycobacterium tuberculosis is the causative agent that ingresses within the host cells. The approved conventional regimen, though the only viable option available, is unfavorably impacting the quality of life of the affected individual. Despite newer antibiotics gaining light, there is an unending demand for more therapeutic alternatives. Therefore, substantial continuous endeavors are been undertaken to come up with novel strategies to curb the disease, the stepping stone being nanotechnology. This approach is instrumental in overcoming the anomalies associated with conventional therapy owing to their intriguing attributes and leads to optimization of the therapeutic effect to a certain extent. This review focusses on the different types of nanocarrier systems that are being currently explored by the researchers for the delivery of anti-tubercular drugs, the outcomes achieved by them, and their prospects.

Simulated biological fluids - a systematic review of their biological relevance and use in relation to inhalation toxicology of particles and fibres

The use of simulated biological fluids (SBFs) is a promising in vitro technique to better understand the release mechanisms and possible in vivo behaviour of materials, including fibres, metal-containing particles and nanomaterials. Applications of SBFs in dissolution tests allow a measure of material biopersistence or, conversely, bioaccessibility that in turn can provide a useful inference of a materials biodistribution, its acute and long-term toxicity, as well as its pathogenicity. Given the wide range of SBFs reported in the literature, a review was conducted, with a focus on fluids used to replicate environments that may be encountered upon material inhalation, including extracellular and intracellular compartments. The review aims to identify when a fluid design can replicate realistic biological conditions, demonstrate operation validation, and/or provide robustness and reproducibility. The studies examined highlight simulated lung fluids (SLFs) that have been shown to suitably replicate physiological conditions, and identify specific components that play a pivotal role in dissolution mechanisms and biological activity; including organic molecules, redox-active species and chelating agents. Material dissolution was not always driven by pH, and likewise not only driven by SLF composition; specific materials and formulations correspond to specific dissolution mechanisms. It is recommended that SLF developments focus on biological predictivity and if not practical, on better biological mimicry, as such an approach ensures results are more likely to reflect in vivo behaviour regardless of the material under investigation.

Nanomaterials for Biomedical Applications: Production, Characterisations, Recent Trends and Difficulties

Designing of nanomaterials has now become a top-priority research goal with a view to developing specific applications in the biomedical fields. In fact, the recent trends in the literature show that there is a lack of in-depth reviews that specifically highlight the current knowledge based on the design and production of nanomaterials. Considerations of size, shape, surface charge and microstructures are important factors in this regard as they affect the performance of nanoparticles (NPs). These parameters are also found to be dependent on their synthesis methods. The characterisation techniques that have been used for the investigation of these nanomaterials are relatively different in their concepts, sample preparation methods and obtained results. Consequently, this review article aims to carry out an in-depth discussion on the recent trends on nanomaterials for biomedical engineering, with a particular emphasis on the choices of the nanomaterials, preparation methods/instruments and characterisations techniques used for designing of nanomaterials. Key applications of these nanomaterials, such as tissue regeneration, medication delivery and wound healing, are also discussed briefly. Covering this knowledge gap will result in a better understanding of the role of nanomaterial design and subsequent larger-scale applications in terms of both its potential and difficulties.

Novel Approaches for the Treatment of Pulmonary Tuberculosis

Tuberculosis (TB) is a contagious airborne disease caused by Mycobacterium tuberculosis, which primarily affects human lungs. The progression of drug-susceptible TB to drug-resistant strains, MDR-TB and XDR-TB, has become worldwide challenge in eliminating TB. The limitations of conventional TB treatment including frequent dosing and prolonged treatment, which results in patient’s noncompliance to the treatment because of treatment-related adverse effects. The non-invasive pulmonary drug administration provides the advantages of targeted-site delivery and avoids first-pass metabolism, which reduced the dose requirement and systemic adverse effects of the therapeutics. With the modification of the drugs with advanced carriers, the formulations may possess sustained released property, which helps in reducing the dosing frequency and enhanced patients’ compliances. The dry powder inhaler formulation is easy to handle and storage as it is relatively stable compared to liquids and suspension. This review mainly highlights the aerosolization properties of dry powder inhalable formulations with different anti-TB agents to understand and estimate the deposition manner of the drug in the lungs. Moreover, the safety profile of the novel dry powder inhaler formulations has been discussed. The results of the studies demonstrated that dry powder inhaler formulation has the potential in enhancing treatment efficacy.

Pulmonary delivery by exploiting doxorubicin and cisplatin co-loaded nanoparticles for metastatic lung cancer therapy

Despite advances in cancer therapy, effective local treatment remains a formidable challenge due to the limit of efficient drug delivery method and the toxicity of chemotherapeutics. In the current study, a combined system was developed for simultaneous delivering doxorubicin (DOX) and cis-platinum (CDDP) to the lungs via pulmonary administration. Methoxy poly(ethylene glycol)-poly(ethylenimine)-poly(l-glutamate) (mPEG-OEI-PLG) copolymers were synthesized as a carrier for the co-delivery of DOX and CDDP. The co-delivery nanoparticles (Co-NPs) were formed with mPEG-OEI-PLG via electrostatic interactions for DOX loading and chelate interactions for CDDP loading, respectively. The results of in vitro cytotoxicity assays against B16F10 cell line showed that Co-NPs exhibited higher cytotoxicity than those treated with either DOX or CDDP alone. In the B16F10 tumor-bearing mice models, local delivery of Co-NPs by pulmonary administration demonstrated that Co-NPs had highly efficient accumulation in the lungs, especially in the tumor tissues of the lungs, but rarely in normal lung tissues. Moreover, Co-NPs exhibited higher anti-tumor efficiency for metastatic lung cancer than that in the single treatment of DOX or CDDP, while no obvious side effects were observed during the pulmonary treatment. The present pulmonary delivery by exploiting co-loaded nanoparticles was proved to be a promising drug delivery strategy for effective lung cancer therapy.

Technological development of microemulsions with perspectives for pain treatment: a patent review

INTRODUCTION

Microemulsions are thermodynamically stable translucent systems widely used for systemic delivery of drugs. The present study is the first to analyze the biotechnological potential of microemulsion systems for therapeutic purposes, through transdermal route, for pain treatment.

AREAS COVERED

Patents were searched in the World Intellectual Property Organization (WIPO), European Patent Office (Espacenet), United States Patent and Trademark Office (USPTO) and National Institute of Intellectual Property (INPI). The inclusion criteria were published patents containing the keywords; 'microemulsion' and 'transdermal' in their title or abstract. 208 patents were found. However, only those patents which mentioned in their abstract or in their description the use of microemulsion system (object of invention) for pain treatment were selected. Were excluded duplicate patents and those that did not report pharmacological use of MEs specifically for pain treatment. Thus, sixteen patents were selected and described in the present study.

EXPERT OPINION

Patents were found that focused specifically on the development process of microemulsion systems, the inclusion of essential oils in microemulsions, which place microemulsions as delivery systems for NSAIDs and other substances, as well as microemulsions for transdermal administration. These studies reinforce the therapeutic applicability of MEs in the treatment of acute and chronic pain.

Inhalable Fucoidan Microparticles Combining Two Antitubercular Drugs with Potential Application in Pulmonary Tuberculosis Therapy

The pulmonary delivery of antitubercular drugs is a promising approach to treat lung tuberculosis. This strategy not only allows targeting the infected organ instantly, it can also reduce the systemic adverse effects of the antibiotics. In light of that, this work aimed at producing fucoidan-based inhalable microparticles that are able to associate a combination of two first-line antitubercular drugs in a single formulation. Fucoidan is a polysaccharide composed of chemical units that have been reported to be specifically recognised by alveolar macrophages (the hosts of Mycobacterium). Inhalable fucoidan microparticles were successfully produced, effectively associating isoniazid (97%) and rifabutin (95%) simultaneously. Furthermore, the produced microparticles presented adequate aerodynamic properties for pulmonary delivery with potential to reach the respiratory zone, with a mass median aerodynamic diameter (MMAD) between 3.6⁻3.9 µm. The formulation evidenced no cytotoxic effects on lung epithelial cells (A549), although mild toxicity was observed on macrophage-differentiated THP-1 cells at the highest tested concentration (1 mg/mL). Fucoidan microparticles also exhibited a propensity to be captured by macrophages in a dose-dependent manner, as well as an ability to activate the target cells. Furthermore, drug-loaded microparticles effectively inhibited mycobacterial growth in vitro. Thus, the produced fucoidan microparticles are considered to hold potential as pulmonary delivery systems for the treatment of tuberculosis.