In-vitro and ex-vivo characterization of novel mannosylated gelatin nanoparticles of linezolid by quality-by-design approach

Quality-by-Design-Driven Nanostructured Lipid Scaffold of Apixaban: Optimization, Characterization, and Pharmacokinetic Evaluation

Apixaban, an anticoagulant, is limited in its efficacy due to poor solubility, low bioavailability, and extensive metabolism. This study investigates the application of nanostructured lipid carriers (NLCs) to enhance the bioavailability of Apixaban. NLCs were prepared using the high-pressure homogenization method. The influence of independent variables, viz., the amount of Tween 80, HPH pressure, and the number of HPH cycles, were studied using a 23 factorial design. The average particle size, PDI, zeta potential, and entrapment efficiency of the optimized NLCs were found to be 232 ± 23 nm, with 0.514 ± 0.13 PDI and zeta potential of about -21.9 ± 2.1 mV, respectively. Additionally, concerning the thermal and crystallographic properties of the drug, the NLCs showed drug entrapment without altering its potency. The in-vitro drug release studies revealed an immediate release pattern, followed by sustained release for up to 48 h. In-vivo pharmacokinetic experiments demonstrated that Apixaban-loaded NLCs exhibited higher values of t1/2 (27.76 ± 1.18 h), AUC0-∞ (19,568.7 ± 1067.6 ng·h/mL), and Cmax (585.3 ± 87.6 ng/mL) compared to free drugs, indicating improved bioavailability. Moreover, a decrease in the elimination rate constant (Kel) reflected the sustained effect of Apixaban with NLCs. NLCs offer improved oral absorption rates and enhanced therapeutic impact compared to free drugs, potentially reducing dose frequency and improving patient outcomes.

Mannose Ligands for Mannose Receptor Targeting

The mannose receptor (MR, CD 206) is an endocytic receptor primarily expressed by macrophages and dendritic cells, which plays a critical role in both endocytosis and antigen processing and presentation. MR carbohydrate recognition domains (CRDs) exhibit a high binding affinity for branched and linear oligosaccharides. Furthermore, multivalent mannose presentation on the various templates like peptides, proteins, polymers, micelles, and dendrimers was proven to be a valuable approach for the selective and efficient delivery of various therapeutically active agents to MR. This review provides a detailed account of the most relevant and recent aspects of the synthesis and application of mannosylated bioactive formulations for MR-mediated delivery in treatments of cancer and other infectious diseases. It further highlights recent findings related to the necessary structural features of the mannose-containing ligands for successful binding to the MR.

Green Synthesis of Highly Fluorescent Carbon Dots from Bovine Serum Albumin for Linezolid Drug Delivery as Potential Wound Healing Biomaterial: Bio-Synergistic Approach, Antibacterial Activity, and In Vitro and Ex Vivo Evaluation

A simple and green approach was developed to produce novel highly fluorescent bovine serum albumin carbon dots (BCDs) via facile one-step hydrothermal treatment, using bovine serum albumin as a precursor carbon source. Inherent blue photoluminescence of the synthesized BCDs provided a maximum photostability of 90.5 ± 1.2% and was characterized via TEM, FT-IR, XPS, XRD, UV-visible, and zeta potential analyses. By virtue of their extremely small size, intrinsic optical and photoluminescence properties, superior photostability, and useful non-covalent interactions with the synthetic oxazolidinone antibiotic linezolid (LNZ), BCDs were investigated as fluorescent nano-biocarriers for LNZ drug delivery. The release profile of LNZ from the drug delivery system (LNZ-BCDs) revealed a distinct biphasic release, which is beneficial for mollifying the lethal incidents associated with wound infection. The effective wound healing performance of the developed LNZ-BCDs were evaluated through various in vitro and ex vivo assays such as MTT, ex vivo hemolysis, in vitro antibacterial activity, in vitro skin-related enzyme inhibition, and scratch wound healing assays. The examination of LNZ-BCDs as an efficient wound healing biomaterial illustrated excellent biocompatibility and low cytotoxicity against normal human skin fibroblast (HSF) cell line, indicating distinct antibacterial activity against the most common wound infectious pathogens including Staphylococcus aureus (ATCC^® 25922) and methicillin-resistant Staphylococcus aureus, robust anti-elastase, anti-collagenase, and anti-tyrosinase activities, and enhanced cell proliferation and migration effect. The obtained results confirmed the feasibility of using the newly designed fluorescent LNZ-BCDs nano-bioconjugate as a unique antibacterial biomaterial for effective wound healing and tissue regeneration. Besides, the greenly synthesized BCDs could be considered as a great potential substitute for toxic nanoparticles in biomedical applications due to their biocompatibility and intense fluorescence characteristics and in pharmaceutical industries as promising drug delivery nano-biocarriers for effective wound healing applications.

Inhalable Mannosylated Rifampicin–Curcumin Co-Loaded Nanomicelles with Enhanced In Vitro Antimicrobial Efficacy for an Optimized Pulmonary Tuberculosis Therapy

Among respiratory infections, tuberculosis was the second deadliest infectious disease in 2020 behind COVID-19. Inhalable nanocarriers offer the possibility of actively targeting anti-tuberculosis drugs to the lungs, especially to alveolar macrophages (cellular reservoirs of the Mycobacterium tuberculosis). Our strategy was based on the development of a mannose-decorated micellar nanoformulation based in Soluplus^® to co-encapsulate rifampicin and curcumin. The former is one of the most effective anti-tuberculosis first-line drugs, while curcumin has demonstrated potential anti-mycobacterial properties. Mannose-coated rifampicin (10 mg/mL)–curcumin (5 mg/mL)-loaded polymeric micelles (10% w/v) demonstrated excellent colloidal properties with micellar size ~108 ± 1 nm after freeze-drying, and they remain stable under dilution in simulated interstitial lung fluid. Drug-loaded polymeric micelles were suitable for drug delivery to the deep lung with lung accumulation, according to the in vitro nebulization studies and the in vivo biodistribution assays of radiolabeled (99mTc) polymeric micelles, respectively. Hence, the nanoformulation did not exhibit hemolytic potential. Interestingly, the addition of mannose significantly improved (5.2-fold) the microbicidal efficacy against Mycobacterium tuberculosis H37Rv of the drug-co-loaded systems in comparison with their counterpart mannose-free polymeric micelles. Thus, this novel inhaled nanoformulation has demonstrated its potential for active drug delivery in pulmonary tuberculosis therapy.

In vitro and in vivo characterization of Entacapone-loaded nanostructured lipid carriers developed by quality-by-design approach

Entacapone, a reversible catechol-o-methyl transferase inhibitor, is used to enhance the action of dopamine agonists by reducing their metabolism and the 'Wearing-off' effects associated with long-term use in the treatment of Parkinson's disease. It is used as an adjunct to levodopa/Carbidopa therapy. Due to limited dissolution and first-pass clearance, it suffers low and variable bioavailability issues. To overcome this problem, the present study aims to explore the potential of nanostructured lipid carriers (NLCs) for the delivery of Entacapone. The Quality by Design (QbD) approach was used for the systematic development of NLCs. The 2³ full factorial designs were investigated using Design-Expert®11 software. The three independent variables namely content of total lipid (X1), surfactant (X2), and sonication time (X3) were optimized against two responses namely particle size and entrapment efficiency. The optimized NLCs were characterized for their size, surface morphology, entrapment efficiency, drug release, thermal and crystallographic studies. In-vivo pharmacokinetic studies in Entacapone-loaded NLCs showed an increase in t_1/2, AUC_0-∞, MRT compared to free drug. The reduction in elimination (Kel) depicts the prolonged action of Entacapone by loading in NLCs. The results displayed Entacapone-loaded NLCs have promising potential for oral delivery and enhanced therapeutic effect which otherwise was a major issue.

Oxazolidinone Antibiotics: Chemical, Biological and Analytical Aspects

This review covers the main aspects concerning the chemistry, the biological activity and the analytical determination of oxazolidinones, the only new class of synthetic antibiotics advanced in clinical use over the past 50 years. They are characterized by a chemical structure including the oxazolidone ring with the S configuration of substituent at C5, the acylaminomethyl group linked to C5 and the N-aryl substituent. The synthesis of oxazolidinones has gained increasing interest due to their unique mechanism of action that assures high antibiotic efficiency and low susceptibility to resistance mechanisms. Here, the main features of oxazolidinone antibiotics licensed or under development, such as Linezolid, Sutezolid, Eperezolid, Radezolid, Contezolid, Posizolid, Tedizolid, Delpazolid and TBI-223, are discussed. As they are protein synthesis inhibitors active against a wide spectrum of multidrug-resistant Gram-positive bacteria, their biological activity is carefully analyzed, together with the drug delivery systems recently developed to overcome the poor oxazolidinone water solubility. Finally, the most employed analytical techniques for oxazolidinone determination in different matrices, such as biological fluids, tissues, drugs and natural waters, are reviewed. Most are based on HPLC (High Performance Liquid Chromatography) coupled with UV-Vis or mass spectrometer detectors, but, to a lesser extent are also based on spectrofluorimetry or voltammetry.