Pulmonary Delivery of Triptorelin Loaded in Pluronic Based Nanomicelles in Rat Model

Expanding the arsenal against pulmonary diseases using surface-functionalized polymeric micelles: breakthroughs and bottlenecks

Pulmonary diseases such as lung cancer, asthma and tuberculosis have remained one of the common challenges globally. Polymeric micelles (PMs) have emerged as an effective technique for achieving targeted drug delivery for a local as well as a systemic effect. These PMs encapsulate and protect hydrophobic drugs, increase pulmonary targeting, decrease side effects and enhance drug efficacy through the inhalation route. In the current review, emphasis has been placed on the different barriers encountered by the drugs given via the pulmonary route and the mechanism of PMs in achieving drug targeting. The applications of PMs in different pulmonary diseases have also been discussed in detail.

Polymeric Drug Delivery System Based on Pluronics for Cancer Treatment

Pluronic polymers (pluronics) are a unique class of synthetic triblock copolymers containing hydrophobic polypropylene oxide (PPO) and hydrophilic polyethylene oxide (PEO) arranged in the PEO-PPO-PEO manner. Due to their excellent biocompatibility and amphiphilic properties, pluronics are an ideal and promising biological material, which is widely used in drug delivery, disease diagnosis, and treatment, among other applications. Through self-assembly or in combination with other materials, pluronics can form nano carriers with different morphologies, representing a kind of multifunctional pharmaceutical excipients. In recent years, the utilization of pluronic-based multi-functional drug carriers in tumor treatment has become widespread, and various responsive drug carriers are designed according to the characteristics of the tumor microenvironment, resulting in major progress in tumor therapy. This review introduces the specific role of pluronic-based polymer drug delivery systems in tumor therapy, focusing on their physical and chemical properties as well as the design aspects of pluronic polymers. Finally, using newer literature reports, this review provides insights into the future potential and challenges posed by different pluronic-based polymer drug delivery systems in tumor therapy.

Self-Assemble Amphiphilic PEO-PPO-PEO Tri-Block Co-Polymeric Methotrexate Nanomicelles to Combat MCF7 Cancer Cells

BACKGROUND

Methotrexate (MTX) is a water-insoluble, anti-tumor agent that causes adverse effects like bone marrow suppression, chronic interstitial obstructive pulmonary disease, hepatotoxicity, leukopenia, interstitial pneumonitis and nephrotoxicity with slow drug release rate.

OBJECTIVE

The present study aimed to successfully incorporate MTX into novel-targeted Pluronic (PEOPPO- PEO tri-block co-polymer) F127 polymeric micelles intended for intravenous administration with improved drug loading and sustained release behavior necessary to achieve better efficacy of MTX.

METHODS

MTX-loaded Pluronic F127 micelles were characterized for critical micelle concentration, particle size and zeta potential,¹H NMR, drug loading, encapsulation efficiency characterization, cell uptake, in vitro release study along with partition coefficient and solubilization thermodynamics.

RESULTS

The micellar formulation resulted in nano size 27.32±1.43nm of PF127/SDS, as compared to Pluronic F127 micelles or PF127/Phosphatidyl choline which were 30.52±1.18nm and 154.35±5.5nm in size, respectively. The uptake of PF127/SDS micellar formulation incorporating Rhodamine 123 in MCF7 cancer cells was found to be higher (84.25%) than PF127/PC, PF127 and MTX i.e. 66.26%, 73.59% and 53% respectively. The in vitro MTX release from PF127, PF127/SDS and PF127/PC polymeric micelles formulations was observed to be 69%, 69.5% and 66% at 12 h whereas 80.89%, 77.67% and 78.54% after 24 h, respectively and revealed a sustained release. MTX-loaded PF127/SDS micelles showed high partition coefficient and negative free energy of solubilization compared to PF127 and PF127/PC which signify self-assembly behavior and thermodynamic stability towards higher dissociation.

CONCLUSION

It was finally concluded that MTX-loaded PF127/SDS micelles act as a potential anticancer delivery system in comparison to PF127/PC and PF127 to combat tumor cells by enhancing their cellular uptake targeting with sustained release pattern and reducing the thermodynamic instability. Thus, PF127/SDS micellar formulation can provide a useful alternative dosage form for intravenous administration of MTX.

Poloxamer: A versatile tri-block copolymer for biomedical applications

Poloxamers, also called Pluronic, belong to a unique class of synthetic tri-block copolymers containing central hydrophobic chains of poly(propylene oxide) sandwiched between two hydrophilic chains of poly(ethylene oxide). Some chemical characteristics of poloxamers such as temperature-dependent self-assembly and thermo-reversible behavior along with biocompatibility and physiochemical properties make poloxamer-based biomaterials promising candidates for biomedical application such as tissue engineering and drug delivery. The microstructure, bioactivity, and mechanical properties of poloxamers can be tailored to mimic the behavior of various types of tissues. Moreover, their amphiphilic nature and the potential to self-assemble into the micelles make them promising drug carriers with the ability to improve the drug availability to make cancer cells more vulnerable to drugs. Poloxamers are also used for the modification of hydrophobic tissue-engineered constructs. This article collects the recent advances in design and application of poloxamer-based biomaterials in tissue engineering, drug/gene delivery, theranostic devices, and bioinks for 3D printing. STATEMENT OF SIGNIFICANCE: Poloxamers, also called Pluronic, belong to a unique class of synthetic tri-block copolymers containing central hydrophobic chains of poly(propylene oxide) sandwiched between two hydrophilic chains of poly(ethylene oxide). The microstructure, bioactivity, and mechanical properties of poloxamers can be tailored to mimic the behavior of various types of tissues. Moreover, their amphiphilic nature and the potential to self-assemble into the micelles make them promising drug carriers with the ability to improve the drug availability to make cancer cells more vulnerable to drugs. However, no reports have systematically reviewed the critical role of poloxamer for biomedical applications. Research on poloxamers is growing today opening new scenarios that expand the potential of these biomaterials from "traditional" treatments to a new era of tissue engineering. To the best of our knowledge, this is the first review article in which such issue is systematically reviewed and critically discussed in the light of the existing literature.