PEGylated Fmoc–Amino Acid Conjugates as Effective Nanocarriers for Improved Drug Delivery

Evaluation of Pharmacokinetic and Pharmacodynamic (PK/PD) of Novel Fluorenylmethoxycarbonyl- Phenylalanine Antimicrobial Agent

OBJECTIVE

To assess the pharmacokinetic profile, in-vivo toxicity, and efficacy of 9-Fluorenylmethoxycarbonyl-L-phenylalanine (Fmoc-F) as a potential antibacterial agent, with a focus on its suitability for clinical translation.

METHODS

An RP-HPLC-based bio-analytical method was developed and qualified to quantify Fmoc-F levels in mouse plasma for pharmacokinetic analysis. Oral bioavailability was determined, and in-vivo toxicity was evaluated following intra-peritoneal administration. Efficacy was assessed by measuring the reduction in Staphylococcus aureus burden and survival rates in BALB/c mice.

RESULTS

The RP-HPLC method is highly sensitive, detecting as low as 0.8 µg mL-1 (~ 2 µM) of Fmoc-F in blood plasma. This study revealed that Fmoc-F has an oral bioavailability of 65 ± 18% and suitable pharmacokinetic profile. Further, we showed that intra-peritoneal administration of Fmoc-F is well tolerated by BALB/c mice and Fmoc-F treatment (100 mg/kg, i.p.) significantly reduces Staphylococcus aureus burden from visceral organs in BALB/c mice but falls short in enhancing survival rates at higher bacterial loads.

CONCLUSIONS

The study provides crucial insights into the pharmacokinetic and pharmacodynamic properties of Fmoc-F. The compound displayed favourable oral bioavailability and in-vivo tolerance. Its significant reduction of bacterial burden underscores its potential as a treatment for systemic infections. However, limited effectiveness for severe infections, short half-life, and inflammatory response at higher doses need to be addressed for its clinical application.

Versatile flexible micelles integrating mucosal penetration and intestinal targeting for effectively oral delivery of paclitaxel

The extremely low bioavailability of oral paclitaxel (PTX) mainly due to the complicated gastrointestinal environment, the obstruction of intestinal mucus layer and epithelium barrier. Thus, it is of great significance to construct a coordinative delivery system which can overcome multiple intestinal physicochemical obstacles simultaneously. In this work, a high-density PEGylation-based glycocholic acid-decorated micelles (PTX@GNPs) was constructed by a novel polymer, 9-Fluorenylmethoxycarbonyl-polyethylene glycocholic acid (Fmoc-PEG-GCA). The Fmoc motif in this polymer could encapsulate PTX via π‒π stacking to form the core of micelles, and the low molecular weight and non-long hydrophobic chain of Fmoc ensures the high-density of PEG. Based on this versatile and flexible carriers, PTX@GNPs possess mucus trapping escape ability due to the flexible PEG, and excellent intestine epithelium targeting attributed to the high affinity of GCA with apical sodium-dependent bile acid transporter. The in vitro and in vivo results showed that this oral micelle could enhance oral bioavailability of PTX, and exhibited similar antitumor efficacy to Taxol injection via intravenous route. In addition, oral PTX@GNPs administered with lower dosage within shorter interval could increase in vivo retention time of PTX, which supposed to remodel immune microenvironment and enhance oral chemotherapy efficacy by synergistic effect.

Polymeric Nitric Oxide Delivery Nanoplatforms for Treating Cancer, Cardiovascular Diseases, and Infection

The shortened Abstract is as follows: Therapeutic gas nitric oxide (NO) has demonstrated the unique advances in biomedical applications due to its prominent role in regulating physiological/pathophysiological activities in terms of vasodilation, angiogenesis, chemosensitizing effect, and bactericidal effect. However, it is challenging to deliver NO, due to its short half-life (<5 s) and short diffusion distances (20-160 µm). To address these, various polymeric NO delivery nanoplatforms (PNODNPs) have been developed for cancer therapy, antimicrobial and cardiovascular therapeutics, because of the important advantages of polymeric delivery nanoplatforms in terms of controlled release of therapeutics and the extremely versatile nature. This reviews highlights the recent significant advances made in PNODNPs for NO storing and targeting delivery. The ideal and unique criteria that are required for PNODNPs for treating cancer, cardiovascular diseases and infection, respectively, are summarized. Hopefully, effective storage and targeted delivery of NO in a controlled manner using PNODNPs could pave the way for NO-sensitized synergistic therapy in clinical practice for treating the leading death-causing diseases.

Fatty acid chain length impacts nanonizing capacity of albumin-fatty acid nanomicelles: Enhanced physicochemical property and cellular delivery of poorly water-soluble drug

This study aimed to design the ideal nanonizing vehicle for poorly water-soluble model curcumin (CCM) using fattigation-platform nanotechnology, and to investigate the effects of fatty acid salts chain length on nanonizing CCM and its efficient delivery to different cancer cells. HSA-fatty acid conjugates were synthesized by EDC/NHS coupling. Fattigation-platform nanomicelles (NMs), prepared by film hydration, exhibited uniform and spherical morphology, although, each NM varied in particle size, zeta potential, and critical micelle concentration according to the types of fatty acid. Preliminary solubility studies of albumin conjugates with 5 types of fatty acid salts of different chain lengths revealed that C14 exhibited the highest solubilization of CCM. CCM-loaded HSA-C14 NMs demonstrated the highest drug content (5.35 ± 0.48%) and loading efficiency (95.93 ± 1.87%) compared to other NMs. It exhibited enhanced drug release rate and reduced micelle size in biorelevant dissolution medium. Interestingly, this solubilization approach was well applied in poorly water-soluble docetaxel trihydrate (DTX). Preliminary solubility results of DTX was also corresponded to the stable nanonization phenomenon in biorelevant dissolution medium. Compared to the CCM EtOH solution, HSA-C14 NMs showed higher internalization in cancer cell lines A549 and MCF-7, and consequently, exhibited significantly increased cytotoxicity against both cell lines. Therefore, this study provides a new solubilization approach for poorly water-soluble drugs using fatty acid salts of different chain lengths and their micellar formations via nanonization, which could be a promising tool for targeted cancer therapy using poorly water-soluble drugs.

Subtle chemical modification for enrichment of Fmoc-amino acid at a phospholipid interface

Amino acids including the Fmoc group (9-fluorenylmethyloxycarbonyl) are bioinspired molecules that display intriguing features in self-assembly and biological applications. The influence of a delicate chemical modification between Fmoc-F and Fmoc-Y on the interaction with a phospholipid surface was analyzed. Langmuir monolayers of the 1,2-dimyristoyl-sn-glycero-3-phosphate (DMPA) phospholipid were used to mimic the eukaryotic cell membrane. In situ Brewster angle microscopy and UV-vis reflection spectroscopy provided insights on the effect of the Fmoc-amino acid derivatives on the DMPA phospholipid. The formation of H-bonds between the Fmoc-Y and the DMPA molecules was assessed, demonstrating the crucial role of the hydroxyl group of Fmoc-Y in enhancing the interaction with biosurfaces.

A modest chemical modification of the Fmoc-amino acids led to enhanced interaction with a model surface for biomembrane.

In vitro and in vivo evaluation of a novel mitomycin nanomicelle delivery system

Mitomycin C (MMC), naturally synthesized by Streptomyces caespitosus, is a potent antineoplastic antibiotic for the treatment of various solid tumors. However, the defects of conventional MMC injections have greatly limited its clinical application due to its toxic side effects and non-specific interactions. To solve this problem, the PEG_2k-Fmoc-Ibuprofen (PEG-FIbu) micellar nanocarrier was synthesized and the MMC-loaded micelles (PEG-FIbu/MMC) were prepared by thin film hydration method and characterized. Ibuprofen was used as a hydrophobic domain of PEG-FIbu nanocarrier, and we expect it to synergize with codelivered MMC in the overall antitumor activity. The in vitro release of PEG-FIbu/MMC was examined by dialysis method using MMC injection as a control. Our data suggested that PEG-FIbu/MMC micelles presented appropriate particle size, low CMC value, good stability, high drug loading efficiency and sustained release properties. In vitro cytotoxicity studies with several tumor cell lines showed that the carrier was effective in mediating intracellular delivery of MMC to tumor cells. In vivo pharmacokinetics, tissue distribution and therapeutic study proved that PEG-FIbu/MMC micelles prolonged blood circulation, significantly improved the tumor accumulation and therapeutic efficacy, and reduced undesirable side effect on normal tissues compared to MMC injection. In general, PEG-FIbu/MMC micelles represented an effective strategy to improve the performance for the delivery of MMC and safety of medication.

The introduction of a micellar delivery system of MMC increase efficiency, reduce toxicity and enhance specific interactions in tumor.

Neutrophil-mediated and low density lipoprotein receptor-mediated dual-targeting nanoformulation enhances brain accumulation of scutellarin and exerts neuroprotective effects against ischemic stroke

Delivery of poorly permeable drugs across the blood-brain barrier (BBB) is a great challenge in the treatment of ischemic stroke.

Dual Intratumoral Redox/Enzyme-Responsive NO-Releasing Nanomedicine for the Specific, High-Efficacy, and Low-Toxic Cancer Therapy

Chemotherapy suffers numbers of limitations including poor drug solubility, nonspecific biodistribution, and inevitable adverse effects on normal tissues. Tumor-targeted delivery and intratumoral stimuli-responsive release of drugs by nanomedicines are considered to be highly promising in solving these problems. Compared with traditional chemotherapeutic drugs, high concentration of nitric oxide (NO) exhibits unique anticancer effects. The development of tumor-targeting and intratumoral microenvironment-responsive NO-releasing nanomedicines is highly desired. Here a novel kind of organic-inorganic composite nanomedicine (QM-NPQ@PDHNs) is presented by encapsulating a glutathione S-transferases π (GSTπ)-responsive drug O² -(2,4-dinitro-5-{[2-(β-d-galactopyranosyl olean-12-en-28-oate-3-yl)-oxy-2-oxoethyl] piperazine-1-yl} phenyl) 1-(methylethanolamino)diazen-1-ium-1,2-dilate (NPQ) as NO donor and an aggregation-induced-emission (AIE) red fluorogen QM-2 into the cores of the hybrid nanomicelles (PEGylated disulfide-doped hybrid nanocarriers (PDHNs)) with glutathione (GSH)-responsive shells. The QM-NPQ@PDHN nanomedicine is able to respond to the intratumoral over-expressed GSH and GSTπ, resulting in the responsive biodegradation of the protective organosilica shell and NPQ release, and subsequent NO release within the tumor, respectively, and thus normal organs remain unaffected. This work demonstrates a paradigm of dual intratumoral redox/enzyme-responsive NO-release nanomedicine for tumor-specific and high-efficacy cancer therapy.

Neutrophil affinity for PGP and HAIYPRH (T7) peptide dual-ligand functionalized nanoformulation enhances the brain delivery of tanshinone IIA and exerts neuroprotective effects against ischemic stroke by inhibiting proinflammatory signaling pathways

A great challenge to the therapy of ischemic stroke is the poor physicochemical properties and inability of the drug to cross the blood–brain barrier (BBB).

A novel cabazitaxel-loaded polymeric micelle system with superior in vitro stability and long blood circulation time

Cabazitaxel (CTX) is a second-generation semisynthetic taxane that demonstrates antitumor activity superior to docetaxel. However, the low aqueous solubility of CTX has hampered its use as a therapeutic agent. In this work, CTX-loaded N-t-butoxycarbonyl-L-phenylalanine end-capped monomethyl poly (ethylene glycol)-block-poly (D,L-lactide) (mPEG-PLA-Phe(Boc)/CTX) micelles were prepared to improve the solubility of CTX while retaining its superior stability before accessing the tumor site. The mPEG-PLA-Phe(Boc)/CTX micelles showed excellent stability in vitro compared with mPEG-PLA/CTX micelles. When stored at 25 °C, the mPEG-PLA/CTX micelles tended to aggregate within 1 h, whereas the mPEG-PLA-Phe(Boc)/CTX micelles were uniformly transparent even after three weeks. Dilution of mPEG-PLA/CTX micelles widened their size distribution and decreased the encapsulation efficiency, while significant change was not found in mPEG-PLA-Phe(Boc)/CTX micelles, even when diluted 1000-fold. Pharmacokinetic results in Sprague-Dawley rats indicated that, compared with Jevtana(®), intravenous administration of mPEG-PLA-Phe(Boc)/CTX micelles stably retained the CTX in plasma with 26.03-fold larger of the area under the time-concentration curve, 2.13-fold longer of the half-life, and 9.99-fold higher of the maximum concentration. In conclusion, mPEG-PLA-Phe(Boc) micelle may be a potential nanocarrier not only to improve the solubility of CTX but also to prolong the blood circulation time, which results in improved biological activity.

Effective co-delivery of doxorubicin and dasatinib using a PEG-Fmoc nanocarrier for combination cancer chemotherapy

A simple PEGylated peptidic nanocarrier, PEG5000-lysyl-(α-Fmoc-ε-Cbz-lysine)2 (PLFCL), was developed for effective co-delivery of doxorubicin (DOX) and dasatinib (DAS) for combination chemotherapy. Significant synergy of DOX and DAS in inhibition of cancer cell proliferation was demonstrated in various types of cancer cells, including breast, prostate, and colon cancers. Co-encapsulation of the two agents was facilitated by incorporation of 9-Fluorenylmethoxycarbonyl (Fmoc) and carboxybenzyl (Cbz) groups into a nanocarrier for effective carrier-drug interactions. Spherical nanomicelles with a small size of ∼30 nm were self-assembled by PLFCL. Strong carrier/drug intermolecular π-π stacking was demonstrated in fluorescence quenching and UV absorption. Fluorescence study showed more effective accumulation of DOX in nuclei of cancer cells following treatment with DOX&DAS/PLFCL in comparison with cells treated with DOX/PLFCL. DOX&DAS/PLFCL micelles were also more effective than other treatments in inhibiting the proliferation and migration of cultured cancer cells. Finally, a superior anti-tumor activity was demonstrated with DOX&DAS/PLFCL. A tumor growth inhibition rate of 95% was achieved at a respective dose of 5 mg/kg for DOX and DAS in a murine breast cancer model. Our nanocarrier may represent a simple and effective system that could facilitate clinical translation of this promising multi-agent regimen in combination chemotherapy.