Efficient loading of ethionamide in cyclodextrin-based carriers offers enhanced solubility and inhibition of drug crystallization

Addressing the complexities in measuring cyclodextrin-sterol binding constants: A multidimensional study

A class of cyclodextrin (CD) dimers has emerged as a potential new treatment for atherosclerosis; they work by forming strong, soluble inclusion complexes with oxysterols, allowing the body to reduce and heal arterial plaques. However, characterizing the interactions between CD dimers and oxysterols presents formidable challenges due to low sterol solubility, the synthesis of modified CDs resulting in varying number and position of molecular substitutions, and the diversity of interaction mechanisms. To address these challenges and illuminate the nuances of CD-sterol interactions, we have used multiple orthogonal approaches for a comprehensive characterization. Results obtained from three independent techniques - metadynamics simulations, competitive isothermal titration calorimetry, and circular dichroism - to quantify CD-sterol binding are presented. The objective of this study is to obtain the binding constants and gain insights into the intricate nature of the system, while accounting for the advantages and limitations of each method. Notably, our findings demonstrate ∼1000× stronger affinity of the CD dimer for 7-ketocholesterol in comparison to cholesterol for the 1:1 complex in direct binding assays. These methodologies and findings not only enhance our understanding of CD dimer-sterol interactions, but could also be generally applicable to prediction and quantification of other challenging host-guest complex systems.

Nanosized Drug Delivery Systems to Fight Tuberculosis

Tuberculosis (TB) is currently the second deadliest infectious disease. Existing antitubercular therapies are long, complex, and have severe side effects that result in low patient compliance. In this context, nanosized drug delivery systems (DDSs) have the potential to optimize the treatment's efficiency while reducing its toxicity. Hundreds of publications illustrate the growing interest in this field. In this review, the main challenges related to the use of drug nanocarriers to fight TB are overviewed. Relevant publications regarding DDSs for the treatment of TB are classified according to the encapsulated drugs, from first-line to second-line drugs. The physicochemical and biological properties of the investigated formulations are listed. DDSs could simultaneously (i) optimize the therapy's antibacterial effects; (ii) reduce the doses; (iii) reduce the posology; (iv) diminish the toxicity; and as a global result, (v) mitigate the emergence of resistant strains. Moreover, we highlight that host-directed therapy using nanoparticles (NPs) is a recent promising trend. Although the research on nanosized DDSs for TB treatment is expanding, clinical applications have yet to be developed. Most studies are only dedicated to the development of new formulations, without the in vivo proof of concept. In the near future, it is expected that NPs prepared by "green" scalable methods, with intrinsic antibacterial properties and capable of co-encapsulating synergistic drugs, may find applications to fight TB.

Three-in-one: exploration of co-encapsulation of cabazitaxel, bicalutamide and chlorin e6 in new mixed cyclodextrin-crosslinked polymers

Three-in-one: a single bCyD polymer easily prepared in water is used to co-encapsulate cabazitaxel and bicalutamide with chlorin e6 affording a nanoplatform to implement multimodal cancer therapy.

Implementation of Water-Soluble Cyclodextrin-Based Polymers in Biomedical Applications: How Far are we?

Cyclodextrin-based polymers can be prepared starting from the naturally occurring monomers following green and low-cost procedures. They can be selectively derivatized pre- or post-polymerization allowing to fine-tune functionalities of ad hoc customized polymers. Preparation nowadays has reached the 100 g scale thanks also to the interest of industries in these extremely versatile compounds. During the last 15 years these macromolecules have been the object of intense investigations in view of possible biomedical applications as the ultimate goal and large amounts of scientific data are now available. Compared to their monomeric models, already used in the formulation of various therapeutic agents, they display superior behavior in terms of their solubility in water and solubilizing power towards drugs incompatible with biological fluids. Moreover, they allow the combination of more than one type of therapeutic agent in the polymeric system. In this review we provide a complete state-of-the-art on the knowledge and potentialities of water-soluble cyclodextrin-based polymers as therapeutic agents as well as carrier systems for different types of therapeutics to implement combination therapy. Finally, we give a perspective on their assets for innovation in disease treatment as well as their limits that still need to be addressed. This article is protected by copyright. All rights reserved.

A novel codrug made of the combination of ethionamide and its potentiating booster: synthesis, self-assembly into nanoparticles and antimycobacterial evaluation

Ethionamide (ETH) is one of the most widely used second-line chemotherapeutic drugs for the treatment of multi-drug-resistant tuberculosis. The bioactivation and activity of ETH is dramatically potentiated by a family of molecules called "boosters" among which BDM43266 is one of the most potent. However, the co-administration of these active molecules is hampered by their low solubility in biological media and by the strong tendency of ETH to crystallize. A novel strategy that involves synthesizing a codrug able to self-associate into nanoparticles prone to be taken up by infected macrophages is proposed here. This codrug is designed by tethering N-hydroxymethyl derivatives of both ETH and its booster through a glutaric linker. This codrug self-assembles into nanoparticles of around 200 nm, stable upon extreme dilution without disaggregating as well as upon concentration. The nanoparticles of the codrug can be intranasally administered overcoming the unfavorable physico-chemical profiles of the parent drugs. Intrapulmonary delivery of the codrug nanoparticles to Mtb infected mice via the intranasal route at days 7, 9, 11, 14, 16 and 18 post-infection reduces the bacterial load in the lungs by a factor of 6.

A journey through the emergence of nanomedicines with poly(alkylcyanoacrylate) based nanoparticles

Starting in the late 1970s, the pioneering work of Patrick Couvreur gave birth to the first biodegradable nanoparticles composed of a biodegradable synthetic polymer. These nanoparticles, made of poly(alkylcyanoacrylate) (PACA), were the first synthetic polymer-based nanoparticulate drug carriers undergoing a phase III clinical trial so far. Analyzing the journey from the birth of PACA nanoparticles to their clinical evaluation, this paper highlights their remarkable adaptability to bypass various drug delivery challenges found on the way. At present, PACA nanoparticles include a wide range of nanoparticles that can associate drugs of different chemical nature and can be administered in vivo by different routes. The most recent technologies giving the nanoparticles customised functions could also be implemented on this family of nanoparticles. Through different examples, this paper discusses the seminal role of the PACA nanoparticles' family in the development of nanomedicines.

Nanoparticles with high payloads of pipemidic acid, a poorly soluble crystalline drug: drug-initiated polymerization and self-assembly approach

Nowadays, biodegradable polymers such as poly(lactic acid) (PLA), poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(ε-caprolactone) (PCL) remain the most common biomaterials to produce drug-loaded nanoparticles (NPs). Pipemidic acid (PIP) is a poorly soluble antibiotic with a strong tendency to crystallize. PIP incorporation in PLA/PLGA NPs was challenging because of PIP crystals formation and burst release. As PIP had a poor affinity for the NPs, an alternative approach to encapsulation was used, consisting in coupling PIP to PCL. Thus, a PCL-PIP conjugate was successfully synthesized by an original drug-initiated polymerization in a single step without the need of catalyst. PCL-PIP was characterized by NMR, IR, SEC and mass spectrometry. PCL-PIP was used to prepare self-assembled NPs with PIP contents as high as 27% (w/w). The NPs were characterized by microscopy, DLS, NTA and TRPS. This study paves the way towards the production of NPs with high antibiotic payloads by drug-initiated polymerization. Further studies will deal with the synthesis of novel polymer-PIP conjugates with ester bonds between the drug and PCL. PIP can be considered as a model drug and the strategy developed here could be extended to other challenging antibiotics or anticancer drugs and employed to efficiently incorporate them in NPs.

Cyclodextrin-based nanocarriers containing a synergic drug combination: A potential formulation for pulmonary administration of antitubercular drugs

Tuberculosis (TB) remains a major global health problem. The use of ethionamide (ETH), a main second line drug, is associated to severe toxic side-effects due to its low therapeutic index. In this challenging context, "booster" molecules have been synthetized to increase the efficacy of ETH. However, the administration of ETH/booster pair is mostly hampered by the low solubility of these drugs and the tendency of ETH to crystallize. Here, ETH and a poorly water-soluble booster, so-called BDM43266, were simultaneously loaded in polymeric β-cyclodextrin nanoparticles (pβCyD NPs) following a "green" protocol. The interaction of ETH and BDM43266 with pβCyD NPs was investigated by complementary techniques. Remarkably, the inclusion of ETH and BDM43266 pβCyD NPs led to an increase of their apparent solubility in water of 10- and 90-fold, respectively. Competition studies of ETH and BDM43266 for the CyD cavities of pβCyD NPs corroborated the fact that the drugs did not compete with each other, confirming the possibility to simultaneously co-incorporate them in NPs. The drug-loaded NP suspensions could be filtered through 0.22μm filters. Finally, the drug-loaded NPs were passed through a Microsprayer^® to evaluate the feasibility to administer pβCyD NPs by pulmonary route. Each spray delivered a constant amount of both drugs and the NPs were totally recovered after passage through the Microsprayer^®. These promising results pave the way for a future use of pβCyD NPs for the pulmonary delivery of the ETH/BDM43266 pair.