Levofloxacin-proliposomes: opportunities for use in lung tuberculosis

Development of a proliposomal pretomanid dry powder inhaler as a novel alternative approach for combating pulmonary tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) continue as public health concerns. Inhaled drug therapy for TB has substantial benefits in combating the causal agent of TB (Mycobacterium tuberculosis). Pretomanid is a promising candidate in an optional combined regimen for XDR-TB. Pretomanid has demonstrated high potency against M. tuberculosis in both the active and latent phases. Conventional spray drying was used to formulate pretomanid as dry powder inhalers (DPIs) for deep lung delivery using a proliposomal system with a trehalose coarse excipient to enhance the drug solubility. Co-spray drying with L-leucine protected hygroscopic trehalose in formulations and improved powder aerosolization. Higher amounts of L-leucine (40-50 % w/w) resulted in the formation of mesoporous particles with high percentages of drug content and entrapment efficiency. The aerosolized powders demonstrated both geometric and median aerodynamic diameters < 5 µm with > 90 % emitted dose and > 50 % fine particle fraction. Upon reconstitution in simulated physiological fluid, the proliposomes completely converted to liposomes, exhibiting suitable particle sizes (130-300 nm) with stable colloids and improving drug solubility, leading to higher drug dissolution compared to the drug alone. Inhalable pretomanid showed higher antimycobacterial activity than pretomanid alone. The formulations were safe for all broncho-epithelial cell lines and alveolar macrophages, thus indicating their potential suitability for DPIs targeting pulmonary TB.

Inhalable solid lipid nanoparticles of levofloxacin for potential tuberculosis treatment

Delivering novel antimycobacterial agents through the pulmonary route using nanoparticle-based systems shows promise for treating diseases like tuberculosis. However, creating dry powder inhaler (DPI) with suitable aerodynamic characteristics while preserving nanostructure integrity and maintaining bioactivity until the active ingredient travels deeply into the lungs is a difficult challenge. We developed DPI formulations containing levofloxacin-loaded solid lipid nanoparticles (SLNs) via spray-drying technique with tailored aerosolization characteristics for effective inhalation therapy. A range of biophysical techniques, including transmission electron microscopy, confocal microscopy, and scanning electron microscopy were used to measure the morphologies and sizes of the spray-dried microparticles that explored both the geometric and aerodynamic properties. Spray drying substantially reduced the particle sizes of the SLNs while preserving their nanostructural integrity and enhancing aerosol dispersion with efficient mucus penetration. Despite a slower uptake rate compared to plain SLNs, the polyethylene glycol modified formulations exhibited enhanced cellular uptake in both A549 and NR8383 cell lines. The percent viability of Mycobacterium bovis had dropped to nearly 0 % by day 5 for both types of SLNs. Interestingly, the levofloxacin-loaded SLNs demonstrated a lower minimum bactericidal concentration (0.25 µg/mL) compared with pure levofloxacin (1 µg/mL), which indicated the formulations have potential as effective treatments for tuberculosis.

Evaluating the biomolecular interaction between delamanid/formulations and human serum albumin by fluorescence, CD spectroscopy and SPR: Effects on protein conformation, kinetic and thermodynamic parameters

Delamanid is an anti-tuberculosis drug used for the treatment of drug-resistant tuberculosis. Since delamanid has a high protein bound potential, even patients with low albumin levels should experience high and rapid delamanid clearance. However, the interaction between delamanid and albumin should be better controlled to optimize drug efficacy. This study was designed to evaluate the binding characteristics of delamanid to human serum albumin (HSA) using various methods: fluorescence spectroscopy, circular dichroism (CD), surface plasmon resonance (SPR), and molecular docking simulation. The fluorescence emission band without any shift indicated the interaction was not affected by the polarity of the fluorophore microenvironment. The reduction of fluorescence intensity at 344 nm was proportional to the increment of delamanid concentration as a fluorescence quencher. UV-absorbance measurement at the maximum wavelength (λmax, 280 nm) was evaluated using inner filter effect correction. The HSA conformation change was explained by the intermolecular energy transfer between delamanid and HSA during complex formation. The study, which was conducted at temperatures of 298 K, 303 K, and 310 K, revealed a static quenching mechanism that correlated with a decreased of bimolecular quenching rate constant (kq) and binding constant (Ka) at increased temperatures. The Ka was 1.75-3.16 × 104 M-1 with a specific binding site with stoichiometry 1:1. The negative enthalpy change, negative entropy change, and negative Gibbs free energy change demonstrated an exothermic-spontaneous reaction while van der Waals forces and hydrogen bonds played a vital role in the binding. The molecular displacement approach and molecular docking confirmed that the binding occurred mainly in subdomain IIA, which is a hydrophobic pocket of HSA, with a theoretical binding free energy of -9.33 kcal/mol. SPR exhibited a real time negative sensorgram that resulted from deviation of the reflex angle due to ligand delamanid-HSA complex forming. The binding occurred spontaneously after delamanid was presented to the HSA surface. The SPR mathematical fitting model revealed that the association rate constant (kon) was 2.62 × 108 s-1M-1 and the dissociation rate constant (koff) was 5.65 × 10-3 s-1. The complexes were performed with an association constant (KA) of 4.64 × 1010 M-1 and the dissociation constant (KD) of 2.15 × 10-11 M. The binding constant indicated high binding affinity and high stability of the complex in an equilibrium. Modified CD spectra revealed that conformation of the HSA structure was altered by the presence of delamanid during preparation of the proliposomes that led to the reduction of secondary structure stabilization. This was indicated by the percentage decrease of α-helix. These findings are beneficial to understanding delamanid-HSA binding characteristics as well as the drug administration regimen.

Encapsulation and release of hydrocortisone from proliposomes govern vaginal delivery

Topical preparations of hydrocortisone can be used for the anti-inflammatory treatment of the female genital area. Although the drug is a low-strength corticosteroid, systemic absorption and distribution of the drug are the most common safety risks associated with this therapy. In the current investigation, we elucidate the physicochemical properties of lipid-based drug carrier systems that govern the local bioavailability of hydrocortisone for intravaginal administration. For this purpose, we compared various proliposome formulations with a commercial cream. Depending on the availability of physiological acceptors, encapsulation and drug release from the lipid phase were found to be the most important drivers of drug bioavailability. The high permeability of hydrocortisone leads to rapid transport of the drug across the mucosal cell layer as indicated by experiments using HEC-1-A and CaSki cell monolayer models. Under sink conditions, differences in the release from the liposomes as determined in the Dispersion Releaser were almost negligible. However, under non-sink conditions, the drug release plateaued at levels corresponding to the encapsulation efficiency. After redispersion, all liposomal formulations performed better than the commercial drug product indicating that the encapsulation into the lipid phase is the main driver sustaining the release.

A facile one-step jet-millingapproach for the preparation of proliposomal dry powder for inhalationaseffective delivery system for anti-TBtherapeutics

Objective: Physicochemical characterization and assessmentof aerosol dispersion performance of anti-TB proliposome dry powders for inhalation (DPIs) prepared using a single-step jet-milling (JM) approach. Significance: Conventional tuberculosis treatment involves isoniazid and rifampicin as first-line agents in extended oral multi-drug regimes. Liposomal DPIs are emerging as promising alternatives for targeted delivery of anti-TB agents to alveolar macrophages harboring Mycobacterium tuberculosis. However, traditional approaches for liposomal DPI preparation are tedious, time consuming and require sophisticated/expensive equipment. The proposed JM technique for preparation of proliposome DPIs could obviate these limitations and facilitate use of these drugs for more effective and safer treatment. Methods: Proliposome DPIs containing isoniazid and/or rifampicin, cholesterol and cholesterol sulfate were successfully prepared via JM (injection pressure, 7.4 bar; milling pressure, 3.68 bar). Their physicochemical, content uniformity, and in vitro aerosol dispersion performance were assessed using scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, dynamic light scattering/Zeta potential, X-ray diffraction spectroscopy, thermogravimetric analysis, high performance liquid chromatography, and the Next Generation Impactor. Results: The DPIs exhibited consistent, spherically shaped, smooth particles. Drug particles were evenly distributed with acceptable content uniformity. Drug crystallinity was not significantly affected by milling and the formulations had minimal (<2.0%) water content. After reconstitution of theDPIs, the hydrodynamic size was about 370.9 - 556.2nm and charge was-12.3 - -47.3mV. Furthermore, the proliposome DPIs presented emitted dose (69.04 - 89.03%), fine particle fraction,< 4.4 µm (13.7 - 57.8%), and mass median aerodynamic diameter (<3.0 µm), which satisfied the requirements for deep lung delivery. Conclusion: The proposed approach was suitable for preparation of proliposome DPIs that could be deployed for local targeting of the lower respiratory tract for treatment of tuberculosis.

Dry powder inhalers of antitubercular drugs

Despite advancements in the medical and pharmaceutical fields, tuberculosis remains a major health problem globally. Patients do not widely accept the conventional approach to treating tuberculosis (TB) due to prolonged treatment periods with multiple high doses of drugs and associated side effects. A pulmonary route is a non-invasive approach to delivering drugs, hormones, nucleic acid, steroids, proteins, and peptides directly to the lungs, improving the efficacy of the treatment and consequently decreasing the adverse effect of the treatment. This route has been successfully developed for the treatment of various respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), tuberculosis (TB), lung cancer, and other pulmonary infections. The major approaches of inhalation delivery systems include nebulizers, metered-dose inhalers (MDIs), and dry powder inhalers (DPIs). However, dry powder inhalers (DPIs) are more advantageous due to their stability and ability to deliver a high dose of the drug to the lungs. The present review analyzes the modern therapeutic approach of inhaled dry powders, with a special focus on novel drug delivery system (NDDS) based DPIs for the treatment of TB. The article also discussed the challenges of preparing inhalable dry powder formulations for the treatment of TB. The clinical development of inhalable anti-TB drugs is also reviewed.

Development, In-Vitro Characterization and Preclinical Evaluation of Esomeprazole-Encapsulated Proniosomal Formulation for the Enhancement of Anti-Ulcer Activity

Objective: The present study aimed to develop and optimize esomeprazole loaded proniosomes (EZL-PNs) to improve bioavailability and therapeutic efficacy. Method: EZL-PNs formulation was developed by slurry method and optimized by 33 box-Bhekhen statistical design software. Span 60 (surfactant), cholesterol, EZL concentration were taken as independent variables and their effects were evaluated on vesicle size (nm), entrapment efficiency (%, EE) and drug release (%, DR). Furthermore, optimized EZL-PNs (EZL-PNs-opt) formulation was evaluated for ex vivo permeation, pharmacokinetic and ulcer protection activity. Result: The EZL-PNs-opt formulation showed 616 ± 13.21 nm of vesicle size, and 81.21 ± 2.35% of EE. EZL-PNs-opt exhibited negative zeta potential and spherical confirmed scanning electron microscopy. EZL-PNs-opt showed sustained release of EZL (95.07 ± 2.10% in 12 h) than pure EZL dispersion. The ex-vivo gut permeation result exhibited a significantly (p < 0.05) enhanced flux than pure EZL. The in vivo results revealed 4.02-fold enhancement in bioavailability and 61.65% protection in ulcer than pure EZL dispersion (43.82%). Conclusion: Our findings revealed that EZL-PNs formulation could be an alternative delivery system of EZL to enhance oral bioavailability and antiulcer activity.

A drift on liposomes to proliposomes: recent advances and promising approaches

Liposomes are nano-structured vesicles, made up of phospholipids that provide active ingredients at the site of action at a predetermined rate and add the advantage of the sustained-release formulation. Liposomes have stability issues that tend to agglomerate and fuse upon storage, which reflects their drawback. Hence to overcome the aggregation, fusion, hydrolysis, and/or oxidation problems associated with liposomes a new technology named Proliposomes has been introduced. Proliposomes are defined as carbohydrate carriers coated with phospholipids, which upon addition of water generate liposomes. The objective of the review is to cover the concept of proliposomes for pulmonary or alveolar delivery of drugs and compare it with that of liposomes; highlight the methods used for preparations along with the characterization parameters. This is the first systematic review that covers the categorization of liposomes, characteristic methods, and recent examples of drugs from 2015 to 2021, supplied in form of proliposomes to the macrophages as well as others and offers an advantage over the free drug by offering a prolonged drug release and sufficient bioavailability in addition to overcome the stability issues related to liposomes. Since this is a very new technology and many scientists are continuously working in this field to make the drug available for clinical trials and ultimately in the market for the targeted delivery of drugs with better storage life.HIGHLIGHTSProliposomes as an alternative to overwhelm the stability and storage-related issues of liposomes.Anhydrous carbohydrate carriers are utilized for proliposomal preparation.Inhaled delivery of drugs as solid lipid nanoparticles offers a significant impact on pulmonary tract infections, particularly in cystic fibrosis.Size of liposomes attained after proliposome hydrolysis is critical for drug delivery via respiration.

Nano-Drug Delivery Systems: Possible End to the Rising Threats of Tuberculosis

Tuberculosis (TB) is still one of the deadliest disease across the globe caused by Mycobacterium tuberculosis (Mtb). Mtb invades host macrophages and other immune cells, modifies their lysosome trafficking proteins, prevents phagolysosomes formation, and inhibits the TNF receptor-dependent apoptosis in macrophages and monocytes. Tuberculosis (TB) killed 1.4 million people worldwide in the year 2019. Despite the advancements in tuberculosis (TB) treatments, multidrugresistant tuberculosis (MDR-TB) remains a severe threat to human health. The complications are further compounded by the emergence of MDR/XDR strains and the failure of conventional drug regimens to eradicate the resistant bacterial strains. Thus, new therapeutic approaches aim to ensure cure without relapse, to prevent the occurrence of deaths and emergence of drug-resistant strains. In this context, this review article summarises the essential nanotechnology-related research outcomes in the treatment of tuberculosis (TB), including drug-susceptible and drug-resistant strains of Mtb. The novel anti-tuberculosis drug delivery systems are also being detailed. This article highlights recent advances in tuberculosis (TB) treatments, including the use of novel drug delivery technologies such as solid lipid nanoparticles, liposomes, polymeric micelles, nano-suspensions, nano-emulsion, niosomes, liposomes, polymeric nanoparticles and microparticles for the delivery of anti-TB drugs and hence eradication and control of both drug-susceptible as well as drug-resistant strains of Mtb.

Appraisal of fluoroquinolone-loaded carubinose-linked hybrid nanoparticles for glycotargeting to alveolar macrophages

There is a curious case in Alveolar macrophages (AM), the frontline defence recruits that contain the spread of all intruding bacteria. In response to Mycobacterium tuberculosis (M.tb), AM either contain the spread or are modulated by M.tb to create a region for their replication. The M.tb containing granulomas so formed are organised structures with confined boundaries. The limited availability of drugs inside AM aid drug tolerance and poor therapeutic outcomes in diseases like tuberculosis. The present work proves the glycotargeting efficiency of levofloxacin (LVF) to AM. The optimised formulation developed displayed good safety with 2% hemolysis and a viability of 61.14% on J774A.1 cells. The physicochemical characterisations such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) proved that carubinose linkage was accomplished and LVF is entrapped inside carubinose-linked hybrid formulation (CHF) and hybrid formulation (HF) in amorphous form. The transmission electron microscopy (TEM) images revealed a core-shell structure of HF. The particle size of 471.5 nm estimated through dynamic light scattering (DLS) is enough to achieve active and passive targeting to AM. The nanoparticle tracking analysis (NTA) data revealed that the diluted samples were free from aggregates. Fluorescence-activated cell sorting (FACS) data exhibited excellent uptake via CHF (15 times) and HF(3 times) with reference to plain fluorescein isothiocyanate (FITC). The pharmacokinetic studies revealed that CHF and HF release the entrapped moiety LVF in a controlled manner over 72 h. The stability studies indicated that the modified formulation remains stable over 6 months at 5 ± 3℃. Hence, hybrid systems can be efficiently modified via carubinose to target AM via the parenteral route.

Efficacy and safety of combined isoniazid-rifampicin-pyrazinamide-levofloxacin dry powder inhaler in treatment of pulmonary tuberculosis: A randomized controlled trial

OBJECTIVE

To determine the efficacy and safety of add-on dry powder for inhalation (DPI) of combined anti-TB agents prepared as a particulate system (study group) compared with placebo DPI (control group) in patients diagnosed with pulmonary TB.

METHODS

This study was a randomized, placebo-controlled, double-blinded parallel design. Subjects were pulmonary TB patients, new or re-treatment, aged 18 years or older. The eligible patients were randomly allocated (1:1) to either the study group or the control group using stratified blocked randomization. The add-on DPI of combined anti-TB therapy (each capsule contained isoniazid 5 mg, rifampicin 2 mg, pyrazinamide 16 mg, and levofloxacin 2 mg) was used throughout the course of the standard oral anti-TB treatment. The primary outcome was Mycobacterium tuberculosis (MTB) sputum culture conversion measured after receiving treatment for eight weeks. Secondary outcomes were clinical signs and symptoms of pulmonary TB and adverse drug reactions (ADRs) related to anti-TB agents. The percentages of patients who achieved the primary outcome were compared (95% confidence interval). All analyses were performed using the modified intention-to-treat principle.

RESULTS

91 patients were randomly allocated: 44 to the study group and 47 to the control group. Important baseline data (%peak expiratory flow rate, chest X-ray findings, resistance to anti-TB agents, renal and liver function tests) were similar between the two groups. Although the percentages of patients who achieved the primary outcome were similar in both groups (34/44 [77.3%] in the study group and (34/47 [72.3%] in the control group; relative risk [RR] 1.07, 95% CI 0.84-1.36; p = 0.589), the study group patients seemed to achieve the primary outcome earlier than the control group (22/44 [50.0%] vs 15/47 [31.9%]; RR 1.57, 95% CI 0.94-2.61; p = 0.079) at the end of week 4. Cough was significantly lower in the study group than in the control group (23/44 [52.3%] vs 43/47 [91.5%]; RR 0.57, 95% CI 0.43-0.77; p < 0.001) at week 4 of treatment. Hemoptysis was found in approximately half of each group at baseline. The percentage of patients having hemoptysis was substantially reduced at week 2 of treatment (5 [11.4%] in the study group and 11 [23.0%] in the control group, p = 0.132). Regarding safety outcomes, no dyspnea or severe ADRs were reported. Adverse events (AEs) related to oral anti-TB agents, (e.g. liver function tests) were in normal ranges in most patients in both groups during the treatment. The incidences of common AEs reported (e.g. anorexia, dizziness, numbness, arthralgia, rash, and itching) were similar between the two groups, while the incidences of nausea and vomiting were significantly lower in the study group than the control group (38.6% vs 74.5%, p = 0.001, and 43.2% vs 66.0%, p = 0.029, respectively).

CONCLUSIONS

Add-on combined anti-TB DPI therapy to the standard oral anti-TB treatment did not increase MTB sputum culture conversion at two months of treatment. However, the percentage of patients having cough in the study group was significantly lower than in the control group at two months after treatment. A reduction in cough might represent adequate response to treatment, and result in a decreased risk of spread of infection. Combined anti-TB DPI therapy was safe. Further study investigated in a larger sample using higher strengths of DPI therapy is required.

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.

Proliposome powder or tablets for generating inhalable liposomes using a medical nebulizer

Purpose

The aim of this study was to develop and compare proliposome powder and proliposome tablet formulations for drug delivery from a Pari-LC Sprint nebulizer.

Methods

Proliposome powders were prepared by the slurry method and sorbitol or mannitol carbohydrate carrier were used in a 1:10 and 1:15 w/w lipid phase to carrier ratio. Beclometasone dipropionate (BDP; 2 mol%) was incorporated in the lipid phase. Proliposome powders were compressed into tablets, and liposomes were generated from proliposome powders or tablets within the nebulizer reservoir for subsequent aerosolization.

Results

Comparatively, shorter sputtering times were reported for the tablet formulations (≈ < 2.7±0.45 min), indicating uniform aerosolization. Post-nebulization, liposomes size was larger in the nebulizer reservoir in the range of 7.79±0.48 µm–9.73±1.53 µm for both powder and tablet formulations as compared to freshly prepared liposomes (5.38±0.73 µm–5.85±0.86 µm), suggesting liposome aggregation/fusion in the nebulizer’s reservoir. All formulations exhibited more than 80% mass output regardless of formulation type, but greater BDP proportions (circa 50%) were delivered to the Two-stage Impinger when tablet formulations were used. Moreover, the nebulized droplet median size and size distribution were lower for all tablet formulations in comparison to the powder formulations. Proliposome tablet and powdered formulations demonstrated the ability to generate vesicles that sustained the release of BDP.

Conclusion

Overall, this study showed that proliposome tablets could be disintegrated within a Pari-LC Sprint nebulizer to generate inhalable aerosol, with high drug output and hence can be manufactured on large scale to overcome the storage problems associated with powder formulations.

Pharmacokinetics and in vivo distribution of optimized PLGA nanoparticles for pulmonary delivery of levofloxacin

OBJECTIVES

The aim of this study was to develop and optimize levofloxacin loaded PLGA nanoparticles (LN) for pulmonary delivery employing screening and experimental design and evaluate their in-vitro and in-vivo performance. The objective was to achieve Mass Median Aerodynamic Diameter (MMAD) of LN of less than 5μm, sustain the drug release up to 120 h and a higher AUC/MIC at the site of action.

METHODS

LN were prepared by modified emulsion solvent evaporation technique employing high speed homogenization, probe sonication and subsequent lyophilization.

KEY FINDINGS

The Pareto chart from Placket Burman screening design revealed that homogenization speed and amount of PLGA were found to be significant (P < 0.05). Further analysis by 3 full-factorial design revealed that F-ratio was found to be far greater than the theoretical value (P < 0.05) for each regression model.

CONCLUSION

The optimized formulation with desirability value 0.9612 showed mean particle size of 146 nm, MMAD of 4.40 μm and sustained the drug release up to 120 h in simulated lung fluid. Augmentation in C_max (1.71-fold), AUC 0-∞ (5.46-fold), Mean Residence Time (6.64-fold) and AUC/MIC (6.21-fold) of LN through pulmonary route was found to significantly higher (P < 0.05) than levofloxacin (p. o.).

Inhaled Antibiotics for Mycobacterial Lung Disease

Mycobacterial lung diseases are an increasing global health concern. Tuberculosis and nontuberculous mycobacteria differ in disease severity, epidemiology, and treatment strategies, but there are also a number of similarities. Pathophysiology and disease progression appear to be relatively similar between these two clinical diagnoses, and as a result these difficult to treat pulmonary infections often require similarly extensive treatment durations of multiple systemic drugs. In an effort to improve treatment outcomes for all mycobacterial lung diseases, a significant body of research has investigated the use of inhaled antibiotics. This review discusses previous research into inhaled development programs, as well as ongoing research of inhaled therapies for both nontuberculous mycobacterial lung disease, and tuberculosis. Due to the similarities between the causative agents, this review will also discuss the potential cross-fertilization of development programs between these similar-yet-different diseases. Finally, we will discuss some of the perceived difficulties in developing a clinically utilized inhaled antibiotic for mycobacterial diseases, and potential arguments in favor of the approach.

Cubosomes with surface cross-linked chitosan exhibit sustained release and bioavailability enhancement for vinpocetine

The present study aims to develop cubosomes with surface cross-linked chitosan for sustained drug delivery and enhanced oral bioavailability of vinpocetine (VPT). GMO based liquid cubosomes with VPT loading were prepared by the high pressure homogenization method. In order to enhance the anti-digestion effect, chitosan was cross-linked on cubosomes by the Schiff reaction, followed by solidification via spray drying. The obtained spray-dried cubosomes (chito-cubosomes) are spherical microspheres with nano-sized holes on the surface. After reconstitution, the particle size and zeta potential of chito-cubosomes were determined to be ∼250 nm and +35.9 mV, respectively. In comparison to unmodified liquid cubosomes, chito-cubosomes exhibited a significant anti-digestion effect with a typical sustained release profile. In comparison to a VPT suspension, liquid cubosomes showed a 2.5-fold higher C max and 3.0-fold higher AUC0-∞, while chito-cubosomes further enhanced bioavailability (5.0-fold) with prolonged MRT (2.2-fold) and delayed T max (2.8-fold). The results suggested that chito-cubosomes could be a promising drug carrier for enhancing oral absorption with sustained release behavior.

Discovery of a New Xanthone against Glioma: Synthesis and Development of (Pro)liposome Formulations

Following our previous work on the antitumor activity of acetylated flavonosides, a new acetylated xanthonoside, 3,6-bis(2,3,4,6-tetra-O-acetyl-β-glucopyranosyl)xanthone (2), was synthesized and discovered as a potent inhibitor of tumor cell growth. The synthesis involved the glycosylation of 3,6-di-hydroxyxanthone (1) with acetobromo-α-d-glucose. Glycosylation with silver carbonate decreased the amount of glucose donor needed, comparative to the biphasic glycosylation. Xanthone 2 showed a potent anti-growth activity, with GI₅₀ < 1 μM, in human cell lines of breast, lung, and glioblastoma cancers. Current treatment for invasive brain glioma is still inadequate and new agents against glioblastoma with high brain permeability are urgently needed. To overcome these issues, xanthone 2 was encapsulated in a liposome. To increase the well-known low stability of these drug carriers, a proliposome formulation was developed using the spray drying method. Both formulations were characterized and compared regarding three months stability and in vitro anti-growth activity. While the proliposome formulation showed significantly higher stability, it was at the expense of losing its biocompatibility as a drug carrier in higher concentrations. More importantly, the new xanthone 2 was still able to inhibit the growth of glioblastoma cells after liposome formulation.

Synthesis and physicochemical characterizations of coordination between palladium(ii) metal ions with floroquinolone drugs as medicinal model against cancer cells: novel metallopharmaceuticals

Three new complexes of palladium(ii) floroquinolone drugs (levofloxacin (HLVX), pefloxacin mesylate (HPFX) and lomefloxacin (HLMX)) were prepared in alkaline media at pH = 9.

Sharpening nature's tools for efficient tuberculosis control: A review of the potential role and development of host-directed therapies and strategies for targeted respiratory delivery

Centuries since it was first described, tuberculosis (TB) remains a significant global public health issue. Despite ongoing holistic measures implemented by health authorities and a number of new oral treatments reaching the market, there is still a need for an advanced, efficient TB treatment. An adjunctive, host-directed therapy designed to enhance endogenous pathways and hence compliment current regimens could be the answer. The integration of drug repurposing, including synthetic and naturally occurring compounds, with a targeted drug delivery platform is an attractive development option. In order for a new anti-tubercular treatment to be produced in a timely manner, a multidisciplinary approach should be taken from the outset including stakeholders from academia, the pharmaceutical industry, and regulatory bodies keeping the patient as the key focus. Pre-clinical considerations for the development of a targeted host-directed therapy are discussed here.

Dry powder inhalable formulations for anti-tubercular therapy

Tuberculosis (TB) is an intracellular infectious disease caused by the airborne bacterium, Mycobacterium tuberculosis. Despite considerable research efforts, the treatment of TB continues to be a great challenge in part due to the requirement of prolonged therapy with multiple high-dose drugs and associated side effects. The delivery of pharmacological agents directly to the respiratory system, following the natural route of infection, represents a logical therapeutic approach for treatment or vaccination against TB. Pulmonary delivery is non-invasive, avoids first-pass metabolism in the liver and enables targeting of therapeutic agents to the infection site. Inhaled delivery also potentially reduces the dose requirement and the accompanying side effects. Dry powder is a stable formulation of drug that can be stored without refrigeration compared to liquids and suspensions. The dry powder inhalers are easy to use and suitable for high-dose formulations. This review focuses on the current innovations of inhalable dry powder formulations of drug and vaccine delivery for TB, including the powder production method, preclinical and clinical evaluations of inhaled dry powder over the last decade. Finally, the risks associated with pulmonary therapy are addressed. A novel dry powder formulation with high percentages of respirable particles coupled with a cost effective inhaler device is an appealing platform for TB drug delivery.

Effects of the encapsulation of usnic acid into liposomes and interactions with antituberculous agents against multidrug-resistant tuberculosis clinical isolates

Mycobacterium tuberculosis (Mtb) has acquired resistance and consequently the antibiotic therapeutic options available against this microorganism are limited. In this scenario, the use of usnic acid (UA), a natural compound, encapsulated into liposomes is proposed as a new approach in multidrug-resistant tuberculosis (MDR-TB) therapy. Thus the aim of this study was to evaluate the effect of the encapsulation of UA into liposomes, as well as its combination with antituberculous agents such as rifampicin (RIF) and isoniazid (INH) against MDR-TB clinical isolates. The in vitro antimycobacterial activity of UA-loaded liposomes (UA-Lipo) against MDR-TB was assessed by the microdilution method. The in vitro interaction of UA with antituberculous agents was carried out using checkerboard method. Minimal inhibitory concentration values were 31.25 and 0.98 µg/mL for UA and UA-Lipo, respectively. The results exhibited a synergistic interaction between RIF and UA [fractional inhibitory concentration index (FICI) = 0.31] or UA-Lipo (FICI = 0.28). Regarding INH, the combination of UA or UA-Lipo revealed no marked effect (FICI = 1.30-2.50). The UA-Lipo may be used as a dosage form to improve the antimycobacterial activity of RIF, a first-line drug for the treatment of infections caused by Mtb.

Optimization of levofloxacin-loaded crosslinked chitosan microspheres for inhaled aerosol therapy

The aim of this work was the development of innovative levofloxacin-loaded swellable microspheres (MS) for the dry aerosol therapy of pulmonary chronicPseudomonas aeruginosainfections in Cystic Fibrosis patients. In a first step, a factorial design was applied to optimize formulations of chitosan-based MS with glutaraldehyde as crosslinker. After optimization, other crosslinkers (genipin, glutaric acid and glyceraldehyde) were tested. Analyses of MS included aerodynamic and swelling properties, morphology, drug loading, thermal and chemical characteristics,in vitroantibacterial activity and drug release studies. The prepared MS presented a drug content ranging from 39.8% to 50.8% of levofloxacin in an amorphous or dispersed state, antibacterial activity and fast release profiles. The highest degree of swelling was obtained for MS crosslinked with glutaric acid and genipin. These formulations also presented satisfactory aerodynamic properties, making them a promising alternative, in dry-powder inhalers, to levofloxacin solution for inhalation.

Rifapentine-proliposomes for inhalation: in vitro and in vivo toxicity

Background:

Oral therapy for pulmonary tuberculosis (TB) treatment suffers from the limitation of hepatic metabolism leading insufficient concentration of antitubercular (anti-TB) drugs in alveolar macrophage which harbors Mycobacterium tuberculosis (MTB). Targeted aerosol delivery of antituberculous drug to lung is efficient for treating local lung TB infection.

Objective:

The present study was aimed to evaluate rifapentine (RPT) loaded proliposomal dry powder for inhalation (RLDPI) for anti-TBactivity and cytotoxicity in vitro. In vivo toxicity study was also undertaken in Wistar rats to determine safe concentration of RLDPI for administration.

Materials and Methods:

Anti-TB activity of developed RLDPI was assessed using drug susceptibility testing (DST) on Mycobacteria growth indicator tube (MGIT) method. In vitro cytotoxicity was performed in A549 cell lines and IC₅₀ values were used to compare the cytotoxicity of formulation with pure RPT. In vivo repeated dose toxicity study was undertaken using Wistar rats at three different doses for 28-days by intratracheal insufflations method.

Results:

The results of DST study revealed sensitivity of tubercle bacteria to RLDPI at concentration equivalent to 10 μg/mL of RPT. This study confirmed anti-TB potential of RPT in spray-dried RLDPI, though the spray drying method is reported to reduce activity of drugs. Cytotoxicity study in A549 cells demonstrated that RPT when encapsulated in liposomes as RLDPI was safe to cells as compared to pure RPT. In vivo toxicity study revealed that RPT in the form of RLDPI was safe at 1 and 5 mg/kg dose. However, mortality was seen at higher dose (10 mg/kg), possibly because of liver and kidney damage.

Conclusion:

Thus, these studies demonstrated safety of RLDPI for the treatment of pulmonary TB.

Pulmonary drug delivery systems for tuberculosis treatment

Tuberculosis (TB) remains a major global health problem as it is the second leading cause of death from an infectious disease worldwide, after the human immunodeficiency virus (HIV). Conventional treatments fail either because of poor patient compliance to the drug regimen or due to the emergence of multidrug-resistant tuberculosis. The aim of this review is to give an update on the information available on tuberculosis, its pathogenesis and current antitubercular chemotherapies. Direct lung delivery of anti-TB drugs using pulmonary delivery systems is then reviewed since it appears as an interesting strategy to improve first and second line drugs. A particular focus is place on research performed on inhalable dry powder formulations of antitubercular drugs to target alveolar macrophages where the bacteria develop. Numerous studies show that anti-TB drugs can be incorporated into liposomes, microparticles or nanoparticles which can be delivered as dry powders to the deep lungs for instantaneous, targeted and/or controlled release. Treatments of infected animals show a significant reduction of the number of viable bacteria as well as a decrease in tissue damage. These new formulations appear as interesting alternatives to deliver directly drugs to the lungs and favor efficient TB treatment.

Novel drugs against tuberculosis: a clinician's perspective

The United Nations Millennium Development Goal of reversing the global spread of tuberculosis by 2015 has been offset by the rampant re-emergence of drug-resistant tuberculosis, in particular fluoroquinolone-resistant multidrug-resistant and extensively drug-resistant tuberculosis. After decades of quiescence in the development of antituberculosis medications, bedaquiline and delamanid have been conditionally approved for the treatment of drug-resistant tuberculosis, while several other novel compounds (AZD5847, PA-824, SQ109 and sutezolid) have been evaluated in phase II clinical trials. Before novel drugs can find their place in the battle against drug-resistant tuberculosis, linezolid has been compassionately used with success in the treatment of fluoroquinolone-resistant multidrug-resistant tuberculosis. This review largely discusses six novel drugs that have been evaluated in phase II and III clinical trials, with focus on the clinical evidence for efficacy and safety, potential drug interactions, and prospect for using multiple novel drugs in new regimens.

Respirable nanocarriers as a promising strategy for antitubercular drug delivery

Tuberculosis is considered a fatal respiratory infectious disease that represents a global threat, which must be faced. Despite the availability of oral conventional anti-tuberculosis therapy, the disease is characterized by high progression. The leading causes are poor patient compliance and failure to adhere to the drug regimen primarily due to systemic toxicity. In this context, inhalation therapy as a non-invasive route of administration is capable of increasing local drug concentrations in lung tissues, the primary infection side, by passive targeting as well as reducing the risk of systemic toxicity and hence improving the patient compliance. Nanotechnology represents a promising strategy in the development of inhaled drug delivery systems. Nanocarriers can improve the drug effectiveness and decrease the expected side effects as consequences of their ability to target the drug to the infected area as well as sustain its release in a prolonged manner. The current review summarizes the state-of-the-art in the development of inhaled nanotechnological carriers confined currently available anti-tuberculosis drugs (anti TB) for local and targeting drug delivery specifically, polymeric nanoparticles, solid lipid nanoparticles, nanoliposomes and nanomicelles. Moreover, complexes and ion pairs are also reported. The impact and progress of nanotechnology on the therapeutic effectiveness and patient adherence to anti TB regimen are addressed.

Single step spray drying method to develop proliposomes for inhalation: a systematic study based on quality by design approach

Quality by Design (QbD) is a systematic approach to develop drug products which includes evaluation of formulation parameters to achieve defined final product quality. In the present study principles of QbD were extended to the preparation, in-vitro and in-vivo performance of rifapentine-loaded proliposomes for pulmonary inhalation where final product needs to comply with specific properties. The rifapentine-loaded proliposomes for the treatment of tuberculosis were prepared in single step by spray drying method and independent variables were optimized using factorial design approach. Contour plots and multiple regression analysis were used to study the effect of selected independent variables on dependent variables. The effect of presence of drug: hydrogenated soya phosphatidylcholine (HSPC) and type of charged lipid in the formulation at three levels were studied on mass median diameter (MMD), liposomal vesicle size, % encapsulation efficiency (% EE), mass median aerodynamic diameter (MMAD) and fine particle fraction (FPF) as critical quality attributes. Optimized formulation (R-LDPI-7) with drug: HSPC ratio of 1:2 and stearyl amine as charged lipid were found to give respirable proliposomes with MMAD of 1.56 ± 0.16 μm and FPF of 92.5 ± 1.5%. Sustained drug release with Higuchi diffusion kinetics was achieved from liposomally encapsulated rifapentine. Pulmonary pharmacokinetics of optimized batch R-LDPI-7 revealed longer retention of drug in lungs with 7 fold increase in both, the mean residence time and t1/2 as compared to R-DPI-0. The study results demonstrated the application of QbD principles and design of experiment (DOE) approach to develop drug encapsulated proliposomes for inhalation by spray drying in single step.