Formulation and Intracellular Trafficking of Lipid-Drug Conjugate Nanoparticles Containing a Hydrophilic Antitubercular Drug for Improved Intracellular Delivery to Human Macrophages

Apolipoprotein E3 functionalized lipid-drug conjugated nanoparticles of Levetiracetam for enhanced delivery to the brain: In-vitro cell line studies and in-vivo study

A significant portion of brain-tumor patients suffer from 'brain-tumor-related epilepsy (BTE)' which results in depression, anxiety and hampered quality of life. Conventional anti-epileptic drugs indicate negative interaction with other drugs augmenting the poor outcome of overall therapy. Levetiracetam (LVM) has evidenced effectiveness for BTE but its hydrophilicity restricts the passage into blood-brain barrier. The majority of lipid nanoparticles fails to load hydrophilic drug sufficiently. Therefore, lipid-drug conjugates (LDC) were synthesized using stearic acid via amide bond formation confirmed by FTIR and NMR. The nanoparticles of synthesized LDC were prepared by solvent injection method followed by functionalization with Apolipoprotein E3 (ApoE3@LDC-NP). The nanoparticles were characterized by DSC, XRD, particle size (131.6 ± 1.24 nm), zeta potential (-15.6 ± 0.09 mV), and for storage stability. In-vitro release study indicated initial burst release of 20 ± 0.63 % followed by sustained release up to 30 h (66 ± 1.40 %) for ApoE3@LDC-NP. The cell-line study on HEK293 indicated no significant cytotoxic effect and greater cell uptake through U87MG cell line. The pharmacokinetic and bio-distribution study indicated 2.5-fold greater brain-targeting of ApoE3@LDC-NP as compared to LVM solution. It proved safe in the haemolysis study and exhibited the absence of tissue necrosis. Thus, ApoE3@LDC-NP might be a promising approach for effective brain-targeting of LVM for improved clinical response in BTE.

An expanding horizon of complex injectable products: development and regulatory considerations

There has been a constant evolution in the pharmaceutical market concerning the new technologies imbibed in delivering drug substances for various indications. This is either market-driven or technology-driven to improve the overall therapeutic efficacy and patients' quality of life. The pharmaceutical industry has experienced rapid growth in the area of complex injectable products because of their effectiveness in the unmet market. These novel parenteral products, viz, the nanoparticles, liposomes, microspheres, suspensions, and emulsions, have proven their worth as "Safe and Effective" products. However, the underlying challenges involved in the development, scalability, and characterization of these injectable products are critical. Moreover, the guidelines available do not provide a clear understanding of these complex products, making it difficult to anticipate the regulatory requirements. Thus, it becomes imperative to comprehend the criticalities and develop an understanding of these products. This review discusses various complexities involved in the parenteral products such as complex drug substances, excipients, dosage forms, drug administration devices like pre-filled syringes and injector pens, and its different characterization tools and techniques. The review also provides a brief discussion on the regulatory aspects and associated hurdles with other parenteral products.

In silico identification and synthesis of a multi-drug loaded MOF for treating tuberculosis

Conventional drug delivery systems have been applied to a myriad of active ingredients but may be difficult to tailor for a given drug. Herein, we put forth a new strategy, which designs and selects the drug delivery material by considering the properties of encapsulated drugs (even multiple drugs, simultaneously). Specifically, through an in-silico screening process of 5109 MOFs using grand canonical Monte Carlo simulations, a customized MOF (referred as BIO-MOF-100) was selected and experimentally verified to be biologically stable, and capable of loading 3 anti-Tuberculosis drugs Rifampicin+Isoniazid+Pyrazinamide at 10% + 28% + 23% wt/wt (total > 50% by weight). Notably, the customized BIO-MOF-100 delivery system cleared naturally Pyrazinamide-resistant Bacillus Calmette-Guérin, reduced growth of virulent Erdman infection in macaque macrophages 10-100-fold compared to soluble drugs in vitro and was also significantly reduced Erdman growth in mice. These data suggest that the methodology of identifying-synthesizing materials can be used to generate solutions for challenging applications such as simultaneous delivery of multiple, small hydrophilic and hydrophobic molecules in the same molecular framework.

THP-1 cell line model for tuberculosis: A platform for in vitro macrophage manipulation

Macrophages are large mononuclear phagocytic cells that play a vital role in the immune response. They are present in all body tissues with extremely heterogeneous and plastic phenotypes that adapt to the organs and tissues in which they live and respond in the first-line against invading microorganisms. Tuberculosis (TB) is caused by the pathogenic bacteria Mycobacterium tuberculosis (Mtb), which is among the top 10 global infectious agents and the leading cause of mortality, ranking above human immunodeficiency virus (HIV), as a single infectious agent. Macrophages, upon Mtb infection, not only phagocytose the bacteria and present the antigens to T-cells, but also react rapidly by developing antimycobacterial immune response depending highly on the production of cytokines. However, Mtb is also capable of intracellular survival in instances of sub-optimal activation of macrophages. Hence, several systems have been established to evaluate the Mtb-macrophage interaction, where the THP-1 monocytes have been developed as an attractive model for in vitro polarized monocyte-derived macrophages. This model is extensively used for Mtb as well as other intracellular bacterial studies. Herein, we have summarized the updated implications of the THP-1 model for TB-related studies and discussed the pros and cons compared to other cell models of TB.

Recent Developments in Drug Delivery for Treatment of Tuberculosis by Targeting Macrophages

Tuberculosis (TB) is among the greatest public health and safety concerns in the 21st century, Mycobacterium tuberculosis, which causes TB, infects alveolar macrophages and uses these cells as one of its primary sites of replication. The current TB treatment regimen, which consist of chemotherapy involving a combination of 3-4 antimicrobials for a duration of 6-12 months, is marked with significant side effects, toxicity, and poor compliance. Targeted drug delivery offers a strategy that could overcome many of the problems of current TB treatment by specifically targeting infected macrophages. Recent advances in nanotechnology and material science have opened an avenue to explore drug carriers that actively and passively target macrophages. This approach can increase the drug penetration into macrophages by using ligands on the nanocarrier that interact with specific receptors for macrophages. This review encompasses the recent development of drug carriers specifically targeting macrophages actively and passively. Future directions and challenges associated with development of effective TB treatment is also discussed.

Antibiotic-loaded lipid-based nanocarrier: a promising strategy to overcome bacterial infection

According to the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC), bacterial infections are one of the greatest threats to global health, food production, and life expectancy. In this sense, the development of innovative formulations aiming at greater therapeutic efficacy, safety, and shorter treatment duration compared to conventional products is urgently needed. Lipid-based nanocarriers (LBNs) have demonstrated the potential to enhance the effectiveness of available antibiotics. Among them, liposome, nanoemulsion, solid lipid nanoparticle (SLN), and nanostructured lipid carrier (NLC) are the most promising due to their solid technical background for laboratory and industrial production. This review describes recent advances in developing antibiotic-loaded LBNs against susceptible and resistant bacterial strains and biofilm. LBNs revealed to be a promising alternative to deliver antibiotics due to their superior characteristics compared to conventional preparations, including their modified drug release, improved bioavailability, drug protection against chemical or enzymatic degradation, greater drug loading capacity, and biocompatibility. Antibiotic-loaded LBNs can improve current clinical drug therapy, bring innovative products and rescue discarded antibiotics. Thus, antibiotic-loaded LBNs have potential to open a window of opportunities to continue saving millions of lives and prevent the devastating impact of bacterial infection.

Cationic inhalable particles for enhanced drug delivery to M. tuberculosis infected macrophages

Inhalable microparticle-based drug delivery platforms are being investigated extensively for Tuberculosis (TB) treatment as they offer efficient deposition in lungs and improved pharmacokinetics of the encapsulated cargo. However, the effect of physical parameters of microcarriers on interaction with Mycobacterium tuberculosis (Mtb) infected mammalian cells is underexplored. In this study, we report that Mtb-infected macrophages are highly phagocytic and microparticle surface charge plays a major role in particle internalization by infected cells. Microparticles of different sizes (0.5-2 μm) were internalized in large numbers by Mtb-infected THP-1 macrophages and murine primary Bone Marrow Derived Macrophages in vitro. Drastic improvement in particle uptake was observed with cationic particles in vitro and in mice lungs. Rapid uptake of rifampicin-loaded cationic microparticles allowed high intracellular accumulation of the drug and led to enhanced anti-bacterial function when compared to non-modified rifampicin-loaded microparticles. Cytocompatibility assay and histological analysis in vivo confirmed that the formulations were safe and did not elicit any adverse reaction. Additionally, pulmonary delivery of cationic particles in mice resulted in two-fold higher uptake in resident alveolar macrophages compared to non-modified particles. This study provides a framework for future design of drug carriers to improve delivery of anti-TB drugs inside Mtb-infected cells.

Macrophage Polarization Profiling on Native and Regenerated Silk Biomaterials

We investigated the plasticity and polarization of THP-1 cells on native and regenerated silk-based biomaterials to address the basic paradigm of immune response. Here, we report redox kinetics, adhesion morphology, and nitric oxide release patterns to identify specific subtypes of macrophages at different time points. Water-annealed silk film and native fibrous braids from Bombyx mori silkworms showed higher anti-inflammatory cytokine profiles or M2 subtypes (as evidenced by the enhanced expression of interleukin-10, interleukin-13, and interleukin-4). Ethanol-treated Bombyx mori silk films and Antheraea mylitta braids exhibited higher levels of pro-inflammatory cytokines or the M1 subtype (as evidenced by enhanced expression of interleukin-1, interleukin-6, interleukin-8, interferon-γ, TNF-α, and GM-CSF) in contact with healthy THP monocytes for 14 days; such a long study is unprecedented. Cytokine microarray analysis revealed the transition (M0-M1, M1-M2), plasticity, and stable phenotype of THP-1 cells in a variable stage in contact with different physicochemical properties of silk-based biomaterials. The detailed immunogenicity in the context of the physicochemical properties of native and regenerative silk-based biomaterials will enable us to accurately predict the possibility of a pro-/anti-inflammatory response. It will helps to predict the in vivo reprogramming and avoid fibrosis formation to enhance their clinical translational potential.

Nanocarrier-Based Approaches for the Efficient Delivery of Anti-Tubercular Drugs and Vaccines for Management of Tuberculosis

Drug-resistant species of tuberculosis (TB), which spread faster than traditiona TB, is a severely infectious disease. The conventional drug therapy used in the management of tuberculosis has several challenges linked with adverse effects. Hence, nanotherapeutics served as an emerging technique to overcome problems associated with current treatment. Nanotherapeutics helps to overcome toxicity and poor solubility issues of several drugs used in the management of tuberculosis. Due to their diameter and surface chemistry, nanocarriers encapsulated with antimicrobial drugs are readily taken up by macrophages. Macrophages play a crucial role as they serve as target sites for active and passive targeting for nanocarriers. The surface of the nanocarriers is coated with ligand-specific receptors, which further enhances drug concentration locally and indicates the therapeutic potential of nanocarriers. This review highlights tuberculosis's current facts, figures, challenges associated with conventional treatment, different nanocarrier-based systems, and its application in vaccine development.

Development and validation of UPLC-MS/MS method for in vitro quantitative analysis of pyrazinamide in lipid core-shell nanoarchitectonics for improved metabolic stability

Pyrazinamide (PZA), a medication for tuberculosis, has high aqueous solubility and low permeability, undergoes extensive liver metabolism, and exhibits liver toxicity through its metabolites. To avoid this, PZA in lipid core-shell nanoarchitectonics has been formulated to target lymphatic uptake and provide metabolic stability to the incorporated drug. The UPLC-MS/MS method for reliable in vitro quantitative analysis of pyrazinamide (PZA) in lipid core-shell nanoarchitectonics as per ICH guidance was developed and validated using the HILIC column. The developed UPLC-MS/MS method is a simple, precise, accurate, reproducible, and sensitive method for the estimation of PZA in PZA-loaded lipid core-shell nanoarchitectonics for the in vitro determination of % entrapment efficiency, % loading of pyrazinamide, and microsomal stability of lipid core-shell nanoarchitectonics in human liver microsomes. The % entrapment efficiency was found to be 42.72% (±12.60). Lipid nanoarchitectonics was found to be stable in human liver microsomes, where %QH was found to be 6.20%, that is, low clearance. Thus, this formulation is suitable for preventing PZA-mediated extensive liver metabolism. These findings are relevant for the development of other lipid-mediated, suitable, stable nanoformulations containing PZA through various in vitro methods.

Synthesis, Characterizations, and Use of O-Stearoyl Mannose Ligand-Engineered Lipid Nanoarchitectonics for Alveolar Macrophage Targeting

The main challenging aspect in the management of tuberculosis (TB) diseases is effective alveolar macrophages targeting. Macrophage mannose receptor plays a predominant role in stimulating immune systems by TB pathogen. Our earlier in silico computational studies revealed that O-stearoyl mannose (OSM) possesses a higher affinity with macrophage mannose receptors. Therefore, keeping this in view, we developed OSM with the association of stearic acid and d-mannose as initial reactants by the esterification process. Preliminary confirmation of reaction was assessed with thin-layer chromatography experimentation, whereas further confirmation followed by in vitro characterization with several analytical experimental tools such as fourier transform near-infrared, differential scanning calorimetry, and electrospray ionization-assisted mass spectrometry confirms the formation of the OSM. This synthesized and well-characterized OSM as a ligand was further incubated with surface-engineered lipid nanoarchitectonics to achieve OSM ligand-engineered lipid nanoarchitectonics and earlier explored for its safety study through hemolysis assay and potential in vitro triggering efficiency in human alveolar macrophages (THP-1 cells) to validate its active targeting efficiency. Graphical Abstract [Figure: see text].