Optimization of Rifapentine-Loaded Lipid Nanoparticles Using a Quality-by-Design Strategy

Micro-nanoemulsion and nanoparticle-assisted drug delivery against drug-resistant tuberculosis: recent developments

Tuberculosis (TB) is a major global health problem and the second most prevalent infectious killer after COVID-19. It is caused by Mycobacterium tuberculosis (Mtb) and has become increasingly challenging to treat due to drug resistance. The World Health Organization declared TB a global health emergency in 1993. Drug resistance in TB is driven by mutations in the bacterial genome that can be influenced by prolonged drug exposure and poor patient adherence. The development of drug-resistant forms of TB, such as multidrug resistant, extensively drug resistant, and totally drug resistant, poses significant therapeutic challenges. Researchers are exploring new drugs and novel drug delivery systems, such as nanotechnology-based therapies, to combat drug resistance. Nanodrug delivery offers targeted and precise drug delivery, improves treatment efficacy, and reduces adverse effects. Along with nanoscale drug delivery, a new generation of antibiotics with potent therapeutic efficacy, drug repurposing, and new treatment regimens (combinations) that can tackle the problem of drug resistance in a shorter duration could be promising therapies in clinical settings. However, the clinical translation of nanomedicines faces challenges such as safety, large-scale production, regulatory frameworks, and intellectual property issues. In this review, we present the current status, most recent findings, challenges, and limiting barriers to the use of emulsions and nanoparticles against drug-resistant TB.

Development of tetracycline-modified nanoparticles for bone-targeted delivery of anti-tubercular drug

Background: Since the poor response to existing anti-tuberculosis drugs and low drug concentration in local bone tissues, the traditional drug therapy does not result in satisfactory treatment of osteoarticular tuberculosis. Thus, we report a rifapentine release system with imparted bone targeting potential using tetracycline (TC) -modified nanoparticles (NPs). Methods: TC was conjugated to PLGA-PEG copolymer via a DCC/NHS technique. Rifapentine-loaded NPs were prepared by premix membrane emulsification technique. The resulting NPs were characterized in terms of physicochemical characterization, hemolytic study, cytotoxicity, bone mineral binding ability, in vitro drug release, stability test and antitubercular activity. The pharmacokinetic and biodistribution studies were also performed in mice. Results: Rifapentine loaded TC-PLGA-PEG NPs were proved to be 48.8 nm in size with encapsulation efficiency and drug loading of 83.3% ± 5.5% and 8.1% ± 0.4%, respectively. The release of rifapentine from NPs could be maintained for more than 60 h. Most (68.0%) TC-PLGA-PEG NPs could bind to HAp powder in vitro. The cellular studies revealed that NPs were safe for intravenous administration. In vivo evaluations also revealed that the drug concentration of bone tissue in TC-PLGA-PEG group was significantly higher than that in other groups at all time (p < 0.05). Both NPs could improve pharmacokinetic parameters without evident organ toxicity. The minimal inhibitory concentration of NPs was 0.094 μg/mL, whereas this of free rifapentine was 0.25 μg/mL. Conclusion: Rifapentine loaded TC-PLGA-PEG NPs could increase the amount of rifapentine in bone tissue, prolong drug release in systemic circulation, enhance anti-tuberculosis activity, and thereby reducing dose and frequency of drug therapy for osteoarticular tuberculosis.

Solid Lipid Nanoparticles vs. Nanostructured Lipid Carriers: A Comparative Review

Solid-lipid nanoparticles and nanostructured lipid carriers are delivery systems for the delivery of drugs and other bioactives used in diagnosis, therapy, and treatment procedures. These nanocarriers may enhance the solubility and permeability of drugs, increase their bioavailability, and extend the residence time in the body, combining low toxicity with a targeted delivery. Nanostructured lipid carriers are the second generation of lipid nanoparticles differing from solid lipid nanoparticles in their composition matrix. The use of a liquid lipid together with a solid lipid in nanostructured lipid carrier allows it to load a higher amount of drug, enhance drug release properties, and increase its stability. Therefore, a direct comparison between solid lipid nanoparticles and nanostructured lipid carriers is needed. This review aims to describe solid lipid nanoparticles and nanostructured lipid carriers as drug delivery systems, comparing both, while systematically elucidating their production methodologies, physicochemical characterization, and in vitro and in vivo performance. In addition, the toxicity concerns of these systems are focused on.

Mixed Edge Activators in Ibuprofen-Loaded Transfersomes: An Innovative Optimization Strategy Using Box-Behnken Factorial Design

Transfersomes have been highlighted as an interesting nanotechnology-based approach to facilitate the skin delivery of bioactive compounds. Nevertheless, the properties of these nanosystems still need to be improved to enable knowledge transfer to the pharmaceutical industry and the development of more efficacious topical medicines. Quality-by-design strategies, such as Box-Behnken factorial design (BBD), are in line with the current need to use sustainable processes to develop new formulations. Thus, this work aimed at optimizing the physicochemical properties of transfersomes for cutaneous applications, by applying a BBD strategy to incorporate mixed edge activators with opposing hydrophilic-lipophilic balance (HLB). Tween^® 80 and Span^® 80 were used as edge activators and ibuprofen sodium salt (IBU) was selected as the model drug. After the initial screening of the IBU solubility in aqueous media, a BBD protocol was implemented, and the optimized formulation displayed appropriate physicochemical properties for skin delivery. By comparing the optimized transfersomes to equivalent liposomes, the incorporation of mixed edge activators was found to be beneficial to upgrade the storage stability of the nanosystems. Furthermore, their cytocompatibility was shown by cell viability studies using 3D HaCaT cultures. Altogether, the data herein bode well for future advances in the use of mixed edge activators in transfersomes for the management of skin conditions.

Amoxapine-Loaded Solid Lipid Nanoparticles with Superior Preclinical Pharmacokinetics for Better Brain Delivery: LC-MS/MS and GC-MS Analysis

The tricyclic antidepressant amoxapine (AMX) has been reported for a rapid onset of action compared to other cyclic antidepressants. It has very low solubility and bioavailability due to first-pass metabolism. Therefore, we planned to develop solid lipid nanoparticles (SLNs) of AMX using a single emulsification method to increase its solubility and bioavailability. HPLC and LC-MS/MS methods were developed further to quantify AMX in the formulation, plasma, and brain tissue samples. The formulation was studied for entrapment efficiency, loading, and in vitro drug release. Particle size and ζ potential analyses, AFM, SEM, TEM, DSC, and XRD were used for further characterization. In vivo oral pharmacokinetic and brain pharmacokinetic studies were performed using Wistar rats. The entrapment and loading efficiencies of AMX in SLNs were 85.8 ± 3.42 and 4.5 ± 0.45%, respectively. The developed formulation had a mean particle size of 151.5 ± 7.02 nm and a polydispersity index of 0.40 ± 0.11. DSC and XRD results indicated that AMX was incorporated into the nanocarrier system in an amorphous form. SEM, TEM, and AFM studies of AMX-SLNs confirmed the particles' spherical shape and nanoscale size. AMX solubility increased by approx. 2.67 times compared to the pure drug. The developed LC-MS/MS method was successfully applied to the oral and brain pharmacokinetic study of AMX-loaded SLNs in rats. Oral bioavailability was enhanced 1.6 times compared to the pure drug. The peak plasma concentrations of pure AMX and AMX-SLNs were 617.4 ± 137.4 and 1043.5 ± 150.2 (ng/mL), respectively. AMX-SLNs showed more than 5.8 times brain concentration compared to the pure drug. Based on the findings, it appears that utilizing a solid lipid nanoparticle carrier to transport AMX can be a highly effective delivery method with improved pharmacokinetic properties in the brain. This approach may prove valuable for future antidepressant treatment.

DOPE/CHEMS-Based EGFR-Targeted Immunoliposomes for Docetaxel Delivery: Formulation Development, Physicochemical Characterization and Biological Evaluation on Prostate Cancer Cells

Docetaxel (DTX) is a non-selective antineoplastic agent with low solubility and a series of side effects. The technology of pH-sensitive and anti-epidermal growth factor receptor (anti-EGFR) immunoliposomes aims to increase the selective delivery of the drug in the acidic tumor environment to cells with EFGR overexpression. Thus, the study aimed to develop pH-sensitive liposomes based on DOPE (dioleoylphosphatidylethanolamine) and CHEMS (cholesteryl hemisuccinate), using a Box–Behnken factorial design. Furthermore, we aimed to conjugate the monoclonal antibody cetuximab onto liposomal surface, as well as to thoroughly characterize the nanosystems and evaluate them on prostate cancer cells. The liposomes prepared by hydration of the lipid film and optimized by the Box–Behnken factorial design showed a particle size of 107.2 ± 2.9 nm, a PDI of 0.213 ± 0.005, zeta potential of −21.9 ± 1.8 mV and an encapsulation efficiency of 88.65 ± 20.3%. Together, FTIR, DSC and DRX characterization demonstrated that the drug was properly encapsulated, with reduced drug crystallinity. Drug release was higher in acidic pH. The liposome conjugation with the anti-EGFR antibody cetuximab preserved the physicochemical characteristics and was successful. The liposome containing DTX reached an IC50 at a concentration of 65.74 nM in the PC3 cell line and 28.28 nM in the DU145 cell line. Immunoliposome, in turn, for PC3 cells reached an IC50 of 152.1 nM, and for the DU145 cell line, 12.60 nM, a considerable enhancement of cytotoxicity for the EGFR-positive cell line. Finally, the immunoliposome internalization was faster and greater than that of liposome in the DU145 cell line, with a higher EGFR overexpression. Thus, based on these results, it was possible to obtain a formulation with adequate characteristics of nanometric size, a high encapsulation of DTX and liposomes and particularly immunoliposomes containing DTX, which caused, as expected, a reduction in the viability of prostate cells, with high cellular internalization in EGFR overexpressing cells.

Mitoxantrone-loaded lipid nanoparticles for breast cancer therapy - Quality-by-design approach and efficacy assessment in 2D and 3D in vitro cancer models

Breast cancer is the leading cause of cancer-related deaths among women worldwide. The conventional chemotherapeutic regimens used in the treatment of this disease often lead to severe side-effects and reduced efficacy. In this study, a novel drug delivery system for the chemotherapeutic drug mitoxantrone (Mito) was developed using solid lipid nanoparticles (SLN). The production of the SLN was carried out using an organic-solvent-free, low-cost method and optimized using a Box-Behnken design. SLN presented adequate size for cancer-related applications, more than 90% of EE% and remained stable for at least 6 months. A much higher drug release was obtained at acidic pH (mimicking the endosomal compartment) than plasmatic pH, highlighting the potential of the nanosystem for tumor drug delivery. Additionally, SLN were non-hemolytic and cytocompatible, even at high concentrations of lipid. A significantly higher anti-cancer efficacy was obtained for Mito-loaded SLN comparing to the free drug at different concentrations in MCF-7 2D models. Finally, the nanoformulation was evaluated in heterotypic breast cancer spheroids showing capacity to penetrate the tridimensional structure and ability to induce a high anti-tumoral effect, similarly to the free drug. Overall, these results support that the developed SLN are effective Mito nanocarriers for the treatment of breast cancer.

A holistic QBD approach to design galactose conjugated PLGA polymer and nanoparticles to catch macrophages during intestinal inflammation

Recruited macrophages in inflammation attract various ligand-receptor drug delivery approaches. Galactose bound nanocarriers are promising to catch macrophages because of surface-expressed macrophage galactose type-lectin-C (MGL-2) receptor. The present study reported fabrication of galactose conjugated PLGA (GAL-PLGA) polymer and nanoparticles under quality by design (QBD) approach to investigate macrophages targeting potential at inflamed intestine. GAL-PLGA nanoparticles were fabricated through O/W emulsion-evaporation method under QBD approach and Box-Behnken design. Obtained GAL-PLGA nanoparticles have optimum particle size (~118 nm), drug entrapment (87%) and zeta potential (-9.5). TGA, XPRD and FTIR confirmed stability and negate drug-polymer interactions. Further, nanoparticles have considerable hemocompatibility, biocompatibility and cellular uptake; macrophage uptake was inhibited by D-galactose confirming involvement of MGL-2. Moreover, drug retention studies in the DSS-colitis model provide background for potential of nanoparticles to target and reside inflamed intestine. It is concluded that GAL-PLGA nanoparticles are suitable platform to target macrophages at the inflamed intestine through oral route.

Lipid nanoparticles with improved biopharmaceutical attributes for tuberculosis treatment

Tuberculosis is a topic of relevance worldwide because of the social and biological factors that triggered the disease and the economic burden on the health-care systems that imply its therapeutic treatment. Challenges to handle these issues include, among others, research on technological breakthroughs modifying the drug regimens to facilitate therapy adherence, avoid mycobacterium drug resistance, and minimize toxic side-effects. Lipid nanoparticles arise as a promising strategy in this respect as deduced from the reported scientific data. They are prepared from biodegradable and biocompatible starting materials and compared to the use of the free drugs, the entrapment of active molecules into the carriers might lead to both dose reduction and controlled delivery. Moreover, the target to the lung, the organ mainly affected by the disease, could be possible if the particle surface is modified. Although conclusive statements cannot be made considering the limited number of available research works, looking into what has been achieved up to now definitively encourages to continue investigations in this regard.

Development of Rifapentine-Loaded PLGA-Based Nanoparticles: In vitro Characterisation and in vivo Study in Mice

Background

Tuberculosis (TB) is a leading cause of death amongst infectious diseases. The poor response to antitubercular agents necessitates the long-term use of high drug doses, resulting in low patient compliance, which is the main reason for chemotherapy failure and contributes to the development of multidrug-resistant TB. Patient non-compliance has been a major obstacle in the successful management of TB. The aim of this work was to develop and characterise rifapentine (RPT)-loaded PLGA-based nanoparticles (NPs) for reducing dosing frequency.

Methods

RPT-loaded PLGA and PLGA–PEG NPs were prepared using premix membrane homogenisation combined with solvent evaporation method. The resulting NPs were characterised in terms of physicochemical characteristics, toxicity, cellular uptake and antitubercular activity. NPs were further evaluated for pharmacokinetic and biodistribution studies in mice.

Results

The resulting NPs showed suitable and safe physicochemical characteristics and could be taken up by macrophages. RPT-loaded NPs were more effective against Mycobacterium tuberculosis than free RPT. In vivo studies revealed that NPs could improve pharmacokinetic parameters, particularly for RPT/PLGA–PEG NPs. Moreover, both formulations had no toxicity to the organs of mice and could reduce hepatotoxicity.

Conclusion

The application of PLGA-based NPs as sustained-release delivery vehicles for RPT could prolong drug release, modify pharmacokinetics, increase antitubercular activity and diminish toxicity, thereby allowing low dosage and frequency.