Improving the pharmacokinetics and tissue distribution of pyrinezolid by self-assembled polymeric micelles

Self-Assembly Study of Block Copolypeptoids in Response to pH and Temperature Stimulation

Polypeptoids with well-designed structures have the ability to self-assemble into nanomaterials, which have wide potential applications. In this study, a series of diblock copolypeptoids were synthesized via ring-opening polymerization followed by click chemistry and exhibited both temperature and pH stimulation responsiveness. Under specific temperature and pH conditions, the responsive blocks in the copolypeptoids became hydrophobic and aggregated to form micelles. The self-assembly process was monitored using the UV-Vis and DLS methods, which suggested the reversible transition of free molecules to micelles and bigger aggregates upon instituting temperature and pH changes. By altering the length and proportion of each block, the copolypeptoids displayed varying self-assembly characteristics, and the transition temperature could be tuned. With good biocompatibility, stability, and no cytotoxicity, the polypeptoids reported in this study are expected to be applied as bionanomaterials in fields including drug delivery, tissue engineering, and intelligent biosensing.

Self-Assembled Polymers for Gastrointestinal Tract Targeted Delivery through the Oral Route: An Update

Gastrointestinal tract (GIT) targeted drug delivery systems have gained growing attention as potential carriers for the treatment of different diseases, especially local colonic diseases. They have lower side effects as well as enhanced oral delivery efficiency because of various therapeutics that are vulnerable to acidic and enzymatic degradation in the upper GIT are protected. The novel and unique design of self-assembled nanostructures, such as micelles, hydrogels, and liposomes, which can both respond to external stimuli and be further modified, making them ideal for specific, targeted medical needs and localized drug delivery treatments through the oral route. Therefore, the aim of this review was to summarize and critically discuss the pharmaceutical significance and therapeutic feasibility of a wide range of natural and synthetic biomaterials for efficient drug targeting to GIT using the self-assembly method. Among various types of biomaterials, natural and synthetic polymer-based nanostructures have shown promising targeting potential due to their innate pH responsiveness, sustained and controlled release characteristics, and microbial degradation in the GIT that releases the encapsulated drug moieties.

Development and characterization of a copolymeric micelle containing soluble and insoluble model drugs

OBJECTIVES

Micelles are nano-sized particles with a core-shell structure that are made by natural or synthetic polymers or copolymers. The aim of this study was to develop and characterize a copolymeric micelle using two polymers loaded with hydrophilic and lipophilic drugs.

METHODS

Poly(ethylene glycol) and poly(ε-caprolactone) (PEG-PCL) were used to form a copolymeric micelle which was further loaded with either moxifloxacin or clarithromycin as hydrophilic and lipophilic drug samples, respectively. Characterization tests were done including fourier transform-infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, encapsulation efficiency, particle size, zeta potential, polydispersity index, transmission electron microscopy, and in-vitro release test.

RESULTS

The construction of the copolymer was confirmed by the results of FT-IR and 1H NMR spectroscopy tests. The encapsulation efficiency test exhibited that loading was about 50% for twelve formulations. Particle size, zeta potential, polydispersity index, and transmission electron microscopy confirmed the formation of monodispersed, uniform, and nano-sized micelles with a few negative charges. The kinetic model of release was fitted to the Higuchi model.

CONCLUSIONS

Polymeric micelles consisting of PEG-PCL copolymer were loaded with adequate concentrations of hydrophilic (moxifloxacin) and lipophilic (clarithromycin) model drugs, with a mean particle size under 300 nm. Therefore, copolymeric micelles can be used as a suitable drug delivery system for mucous membranes and skin.

Evaluation of pH-Sensitive Polymeric Micelles Using Citraconic Amide Bonds for the Co-Delivery of Paclitaxel, Etoposide, and Rapamycin

Paclitaxel (PTX), etoposide (ETP), and rapamycin (RAPA) have different mechanisms, allowing multiple pathways to be targeted simultaneously, effectively treating various cancers. However, these drugs have a low hydrosolubility, limiting clinical applications. Therefore, we used pH-sensitive polymeric micelles to effectively control the drug release in cancer cells and to improve the water solubility of PTX, ETP, and RAPA. The synergistic effect of PTX, ETP, and RAPA was evaluated in gastric cancer, and the combination index values were evaluated. Thin-film hydration was used to prepare PTX/ETP/RAPA-loaded mPEG-pH-PCL micelles, and various physicochemical properties of these micelles were evaluated. In vitro cytotoxicity, pH-sensitivity, drug release profiles, in vivo pharmacokinetics, and biodistribution studies of PTX/ETP/RAPA-loaded mPEG-pH-PCL micelles were evaluated. In the pH-sensitivity evaluation, the size of the micelles increased more rapidly at a pH of 5.5 than at a pH of 7.4. The release rate of each drug increased with decreasing pH values in PTX/ETP/RAPA-loaded mPEG-pH-PCL micelles. In vitro and in vivo studies demonstrated that PTX/ETP/RAPA-loaded mPEG-pH-PCL micelles exhibit different drug release behaviors depending on the pH of the tumor and normal tissues and increased bioavailability and circulation time in the blood than solutions. Therefore, we propose that PTX/ETP/RAPA- loaded mPEG-pH-PCL micelles are advantageous for gastric cancer treatment in drug delivery systems.

Highly Biocompatible Apigenin-Loaded Silk Fibroin Nanospheres: Preparation, Characterization, and Anti-Breast-Cancer Activity

Breast cancer is among the most common fatal diseases among women. Low-toxicity apigenin (AGN) is of interest due to its good antitumor activity, but its clinical application is severely limited due to its poor water solubility and low bioavailability. An effective strategy to enhance the anti-breast-cancer activity of AGN is to develop it as a nanodelivery system. Silk fibroin (SF) is an ideal drug carrier with good biocompatibility, biodegradability, and a simple extraction process. This paper develops a novel and efficient apigenin-loaded silk fibroin nanodelivery system (SF-AGN) by nanoprecipitation with SF as a carrier. The system was characterized in terms of morphology, zeta potential, particle size, ultraviolet (UV), infrared (IR), and synchronous thermal analyses (TG-DSC), and the in vitro cytotoxicity and in vivo pharmacokinetics were examined. Finally, the chronic toxicity of SF-AGN in mice was studied. The SF-AGN nanodelivery system has good dispersibility, a hydrated particle size of 163.35 nm, a zeta potential of -18.5 mV, an average drug loading of 6.20%, and good thermal stability. MTT studies showed that SF-AGN significantly enhanced the inhibitory effect of AGN on 4T1 and MDA-MB-231 cells. Pharmacokinetic studies have demonstrated that SF-AGN can dramatically improve the bioavailability of AGN. The results of toxicity experiments showed that SF-AGN is biocompatible and does not alter normal tissues or organs. In sum, the SF-AGN nanodelivery system is a promising drug-delivery system for the clinical treatment of breast cancer.

Strategies to improve the potency of oxazolidinones towards bacterial biofilms

Biofilms are part of the natural lifecycle of bacteria and are known to cause chronic infections that are difficult to treat. Most antibiotics are developed and tested against bacteria in the planktonic state and are ineffective against bacterial biofilms. The oxazolidinones, including the last resort drug linezolid, are one of the main classes of synthetic antibiotics progressed to clinical use in the last 50 years. They have a unique mechanism of action and only develop low levels of resistance in the clinical setting. With the aim of providing insight into strategies to design more potent antibiotic compounds with activity against bacterial biofilms, we review the biofilm activity of clinically approved oxazolidinones and report on structural modifications to oxazolidinones and their delivery systems which lead to enhanced anti‐biofilm activity.

Recent Advances in Oral Nano-Antibiotics for Bacterial Infection Therapy

Bacterial infections are the main infectious diseases and cause of death worldwide. Antibiotics are used to treat various infections ranging from minor to life-threatening ones. The dominant route to administer antibiotics is through oral delivery and subsequent gastrointestinal tract (GIT) absorption. However, the delivery efficiency is limited by many factors such as low drug solubility and/or permeability, gastrointestinal instability, and low antibacterial activity. Nanotechnology has emerged as a novel and efficient tool for targeting drug delivery, and a number of promising nanotherapeutic strategies have been widely explored to overcome these obstacles. In this review, we explore published studies to provide a comprehensive understanding of the recent progress in the area of orally deliverable nano-antibiotic formulations. The first part of this article discusses the functions and underlying mechanisms by which nanomedicines increase the oral absorption of antibiotics. The second part focuses on the classification of oral nano-antibiotics and summarizes the advantages, disadvantages and applications of nanoformulations including lipid, polymer, nanosuspension, carbon nanotubes and mesoporous silica nanoparticles in oral delivery of antibiotics. Lastly, the challenges and future perspective of oral nano-antibiotics for infection disease therapy are discussed. Overall, nanomedicines designed for oral drug delivery system have demonstrated the potential for the improvement and optimization of currently available antibiotic therapies.

Synthesis and characterization of amphiphilic star-shaped copolymers based on β-cyclodextrin for micelles drug delivery

PURPOSE

A series of β-CD amphiphilic star-shaped copolymers with exceptional characteristics were synthesized and their potential as carriers for micelles drug delivery was investigated.

METHODS

A series of amphiphilic copolymers based on β-CD were synthesized by introducing poly (acrylic acid)-co-poly(methyl methacrylate)-poly (vinyl pyrrolidone) or poly (acrylic acid)-co-poly(methyl methacrylate)-co-poly(monoacylated-β-CD)-poly (vinyl pyrrolidone) blocks to the primary hydroxyl group positions of β-CD. The micellization behavior of the copolymers, the synthesis conditions, characteristics, drug release in vitro and tissue distribution of vinpocetine (VP) micelles in vivo were investigated.

RESULTS

Around 60 types of β-CD amphiphilic star-shaped copolymers were successfully synthesized and the critical micelle concentration ranged from 9.80 × 10^-4 to 5.24 × 10^-2g/L. The particle size, drug loading and entrapment efficiency of VP-loaded β-CD-P₄ micelles prepared with optimal formulation were about 65 nm, 21.44 ± 0.14%, and 49.05 ± 0.36%, respectively. The particles had good sphericity. The cumulative release rates at 72 h of VP-loaded β-CD-P₄ micelles in pH 1.0, pH 4.5, pH 6.5, or pH 7.4 media were 93%, 69%, 49%, and 43%, respectively. And, the lung targeting efficiency of VP-loaded β-CD-P₄ micelles was 8.98 times higher than that of VP injection.

CONCLUSION

The VP-loaded β-CD-P₄ micelles exhibited controlled-release property, pH-induced feature and lung targeting capacity compared with VP injection, suggesting that the β-CD-P₄ copolymers are an excellent candidate for micelles drug delivery.

Understanding the prospective of nano-formulations towards the treatment of psoriasis

Psoriasis is a consistently recurring, inflammatory, autoimmune disorder of the skin, affecting about 2-5% of the world population. Abundant therapeutic agents are accessible for the treatment of psoriasis. Nevertheless, none of them are entirely secure and effective to treat the disease without compromising patient compliance. Furthermore, already existing drugs are supposed to restrain the ailment and alleviate the sign and symptoms with no complete cure. However, they focus on restraining the disease and alleviating the symptoms without providing an absolute cure. Therefore there remains a vital challenge, to explore a new drug moiety or delivery system which could safely and effectively manage psoriasis without compromising patient compliance. Furthermore, conventional formulations offer reduced benefit/risk ratio of anti-psoriatic drugs, which limits the use of existing conventional formulations. Novel formulations based on nanocarriers are a promising prospect to overcome the limitation of conventional formulations by offering a reduction in dose, dosing frequency, dose-dependent, side effects with enhanced efficacy. Presently nano-formulations have gained widespread application for effective and safe treatment of psoriasis. The present review primarily focuses on conventional therapeutic strategy and recent advances in lipid-based, polymer-based and metallic nano-formulations of a variety of anti-psoriatic drugs. The practicability of various nanocarrier systems including liposomes, nanostructured lipid carriers, ethosomes, solid lipid nanoparticles, nanocapsules, micelles, dendrimers, gold nanoparticles and silver nanoparticles have been discussed in detail. The review also traces related patents to exemplify the role of various nanoparticles in psoriasis treatment. In a nutshell, nano-formulations remain established as a promising modality for treating psoriasis treatment as they propose better penetration, targeted delivery, enhanced safety, and efficacy.