Doxorubicin-loaded PLGA microparticles with internal pores for long-acting release in pulmonary tumor inhalation treatment

Application of PLGA as a Biodegradable and Biocompatible Polymer for Pulmonary Delivery of Drugs

Pulmonary administration of biodegradable polymeric formulation is beneficial in the treatment of various respiratory diseases. For respiratory delivery, the polymer must be non-toxic, biodegradable, biocompatible, and stable. Poly D, L-lactic-co-glycolic acid (PLGA) is a widely used polymer for inhalable formulations because of its attractive mechanical and processing characteristics which give great opportunities to pharmaceutical industries to formulate novel inhalable products. PLGA has many pharmaceutical applications and its biocompatible nature produces non-toxic degradation products. The degradation of PLGA takes place through the non-enzymatic hydrolytic breakdown of ester bonds to produce free lactic acid and glycolic acid. The biodegradation products of PLGA are eliminated in the form of carbon dioxide (CO₂) and water (H₂O) by the Krebs cycle. The biocompatible properties of PLGA are investigated in various in vivo and in vitro studies. The high structural integrity of PLGA particles provides better stability, excellent drug loading, and sustained drug release. This review provides detailed information about PLGA as an inhalable grade polymer, its synthesis, advantages, physicochemical properties, biodegradability, and biocompatible characteristics. The important formulation aspects that must be considered during the manufacturing of inhalable PLGA formulations and the toxicity of PLGA in the lungs are also discussed in this paper. Additionally, a thorough overview is given on the application of PLGA as a particulate carrier in the treatment of major respiratory diseases, such as cystic fibrosis, lung cancer, tuberculosis, asthma, and pulmonary hypertension.

Inhalable microparticles as drug delivery systems to the lungs in a dry powder formulations

Inhalation-administrated drugs remain an interesting possibility of addressing pulmonary diseases. Direct drug delivery to the lungs allows one to obtain high concentration in the site of action with limited systemic distribution, leading to a more effective therapy with reduced required doses and side effects. On the other hand, there are several difficulties in obtaining a formulation that would meet all the criteria related to physicochemical, aerodynamic and biological properties, which is the reason why only very few of the investigated systems can reach the clinical trial phase and proceed to everyday use as a result. Therefore, we focused on powders consisting of polysaccharides, lipids, proteins or natural and synthetic polymers in the form of microparticles that are delivered by inhalation to the lungs as drug carriers. We summarized the most common trends in research today to provide the best dry powders in the right fraction for inhalation that would be able to release the drug before being removed by natural mechanisms. This review article addresses the most common manufacturing methods with novel modifications, pros and cons of different materials, drug loading capacities with release profiles, and biological properties such as cytocompatibility, bactericidal or anticancer properties.

Etching Bulk Covalent Organic Frameworks into Nanoparticles of Uniform and Controllable Size by the Molecular Exchange Etching Method for Sonodynamic and Immune Combination Antitumor Therapy

To improve the therapeutic effect of sonodynamic therapy (SDT), more effective and stable sonosensitizers and therapeutic strategies are still required. A covalent organic framework (COF) sonosensitizer is developed by using a new nanoscale COF preparation strategy. This strategy uses molecular etching based on the imine exchange reaction to etch the bulk COF into nanoparticles and has universal applicability to imine-bond-based COF. The regular COF structure can prevent the loss of sonodynamic performance caused by the aggregation of porphyrin molecules and improve the chemical stability of the porphyrin unit. In addition, the coordination of Fe³⁺ to COF endows the nanoparticle with chemodynamic therapy performance and glutathione consumption ability. The combination of enhanced SDT and α-PD-L1 antibody achieves a good antitumor effect. The innovative nanoscale COF sonosensitizer preparation strategy provides a new avenue for clinical antitumor therapy.

Pulmonary delivery by exploiting doxorubicin and cisplatin co-loaded nanoparticles for metastatic lung cancer therapy

Despite advances in cancer therapy, effective local treatment remains a formidable challenge due to the limit of efficient drug delivery method and the toxicity of chemotherapeutics. In the current study, a combined system was developed for simultaneous delivering doxorubicin (DOX) and cis-platinum (CDDP) to the lungs via pulmonary administration. Methoxy poly(ethylene glycol)-poly(ethylenimine)-poly(l-glutamate) (mPEG-OEI-PLG) copolymers were synthesized as a carrier for the co-delivery of DOX and CDDP. The co-delivery nanoparticles (Co-NPs) were formed with mPEG-OEI-PLG via electrostatic interactions for DOX loading and chelate interactions for CDDP loading, respectively. The results of in vitro cytotoxicity assays against B16F10 cell line showed that Co-NPs exhibited higher cytotoxicity than those treated with either DOX or CDDP alone. In the B16F10 tumor-bearing mice models, local delivery of Co-NPs by pulmonary administration demonstrated that Co-NPs had highly efficient accumulation in the lungs, especially in the tumor tissues of the lungs, but rarely in normal lung tissues. Moreover, Co-NPs exhibited higher anti-tumor efficiency for metastatic lung cancer than that in the single treatment of DOX or CDDP, while no obvious side effects were observed during the pulmonary treatment. The present pulmonary delivery by exploiting co-loaded nanoparticles was proved to be a promising drug delivery strategy for effective lung cancer therapy.

Reduction-Responsive Polypeptide Micelles for Intracellular Delivery of Antineoplastic Agent

Reduction-responsive methoxy poly(ethylene glycol)-block-poly(S-tert-butylmercapto-L-cysteine) copolymers (i.e., mPEG₁₁₃-b-PBMLC₄ and mPEG₁₁₃-b-PBMLC₉) were facilely synthesized through primary amino-initiated ring-opening polymerization (ROP) of disulfide-containing N-carboxyanhydride monomer. The reduction-responsive block copolymers were then investigated for intracellular delivery of antitumor drug after forming smart micelles in vitro and in vivo. The micelles were denoted as P4M and P9M, respectively. Doxorubicin (DOX) was selected as a model chemotherapeutic agent, which was loaded into micelles via hydrophobic interaction. The drug loading efficiency (DLE) were detected to be 55.4 and 61.7 wt % for P4M and P9M, respectively. The loaded micelles, referred as P4M/DOX and P9M/DOX, exhibited spherical morphologies with hydrodynamic radii of 92.3 ± 2.3 and 80.2 ± 2.8 nm, respectively. Compared to P4M/DOX, P9M/DOX with a smaller size exhibited upregulated cell endocytosis and higher cytotoxicity to human breast cancer MCF-7 cells. Furthermore, the loading micelles, especially P9M/DOX, demonstrated improved antitumor efficacy toward an MCF-7 breast tumor-bearing BALB/c nude mouse model compared with free doxorubicin hydrochloride (DOX·HCl). This was also confirmed by the histopathological and immunohistochemical results. The above results demonstrated that the facially prepared smart polypeptide micelles exhibited a potent prospect in intracellular drug delivery in vitro and in vivo.

Reduction/pH dual-responsive nano-prodrug micelles for controlled drug delivery

We provided a facile strategy to fabricate reduction/pH dual-responsive nano-prodrug micelles for controlled drug delivery.

Poly(d,l-lactic acid)-block-poly(N-(2-hydroxypropyl)methacrylamide) nanoparticles for overcoming accelerated blood clearance and achieving efficient anti-tumor therapy

The substitution of PEG with PHPMA maintained the long circulation of PDLLA-b-PEG and alleviated the accelerated blood clearance (ABC).