Naphthalocyanine as a New Photothermal Actuator for Lipid-Based Drug Delivery Systems

Recent Advances in Nanomedicine for Ocular Fundus Neovascularization Disease Management

As an indispensable part of the human sensory system, visual acuity may be impaired and even develop into irreversible blindness due to various ocular pathologies. Among ocular diseases, fundus neovascularization diseases (FNDs) are prominent etiologies of visual impairment worldwide. Intravitreal injection of anti-vascular endothelial growth factor drugs remains the primary therapy but is hurdled by common complications and incomplete potency. To renovate the current therapeutic modalities, nanomedicine emerged as the times required, which is endowed with advanced capabilities, able to fulfill the effective ocular fundus drug delivery and achieve precise drug release control, thus further improving the therapeutic effect. This review provides a comprehensive summary of advances in nanomedicine for FND management from state-of-the-art studies. First, the current therapeutic modalities for FNDs are thoroughly introduced, focusing on the key challenges of ocular fundus drug delivery. Second, nanocarriers are comprehensively reviewed for ocular posterior drug delivery based on the nanostructures: polymer-based nanocarriers, lipid-based nanocarriers, and inorganic nanoparticles. Thirdly, the characteristics of the fundus microenvironment, their pathological changes during FNDs, and corresponding strategies for constructing smart nanocarriers are elaborated. Furthermore, the challenges and prospects of nanomedicine for FND management are thoroughly discussed.

Light-responsive biomaterials for ocular drug delivery

Light-responsive biomaterials can be used for the delivery of therapeutic drugs and nucleic acids, where the tunable/precise delivery of payload highlights the potential of such biomaterials for treating a variety of conditions. The translucency of eyes and advances of laser technology in ophthalmology make light-responsive delivery of drugs feasible. Importantly, light can be applied in a non-invasive fashion; therefore, light-triggered drug delivery systems have great potential for clinical impact. This review will examine various types of light-responsive polymers and the chemistry that underpins their application as ophthalmic drug delivery systems.

Preparation of Nanostructured Lipid Drug Delivery Particles Using Microfluidic Mixing

BACKGROUND

Cubosomes are highly ordered self-assembled lipid particles analogous to liposomes, but with internal liquid crystalline structure. They are receiving interest as stimuli responsive delivery particles, but their preparation typically requires high energy approaches such as sonication which is not favourable in many applications.

OBJECTIVE

Here we investigated the impact of microfluidic preparation on particle size distribution and internal structure of cubosomes prepared from two different lipid systems, phytantriol and glyceryl monooleate (GMO).

METHODS

The impact of relative flow rates of the aqueous and organic streams, the total flow rate and temperature were investigated in a commercial microfluidic system. The particle size distribution and structure were measured using dynamic light scattering and small angle X-ray scattering respectively.

RESULTS

Phytantriol based particles were robust to different processing conditions, while cubosomes formed using GMO were more sensitive to composition both locally and globally, which reflects their preparation using other techniques.

CONCLUSION

Thus, in summary microfluidics represents a reproducible and versatile method to prepare complex lipid particle dispersions such as cubosomes.

Rational Design of a Famotidine-Ibuprofen Coamorphous System: An Experimental and Theoretical Study

Famotidine (FMT) and ibuprofen (IBU) were used as model drugs to obtain coamorphous systems, where the guanidine moiety of the antacid and the carboxylic group of the nonsteroidal anti-inflammatory drug could potentially participate in H-bonds leading to a given structural motif. The systems were prepared in 3:7, 1:1, and 7:3 FMT and IBU molar ratios, respectively. The latter two became amorphous after 180 min of comilling. FMT-IBU (1:1) exhibited a higher physical stability in assays at 4, 25, and 40 °C up to 60 days. Fourier transform infrared spectroscopy accounted for important modifications in the vibrational behavior of those functional groups, allowing us to ascribe the skill of 1:1 FMT-IBU for remaining amorphous to equimolar interactions between both components. Density functional theory calculations followed by quantum theory of atoms in molecules analysis were then conducted to support the presence of the expected FMT-IBU heterodimer with consequent formation of a R₂²8 structural motif. The electron density (ρ) and its Laplacian (∇²ρ) values suggested a high strength of the specific intermolecular interactions. Molecular dynamics simulations to build an amorphous assembly, followed by radial distribution function analysis on the modeled phase were further employed. The results demonstrate that it is a feasible rational design of a coamorphous system, satisfactorily stabilized by molecular-level interactions leading to the expected motif.

A self-assembled photoresponsive gel consisting of chiral nanofibers

A novel compound based on a glutamic acid skeleton, containing azobenzene as a photoresponsive group and ureidopyrimidinone (UPy) as a connection site, was designed and synthesized. The monomer is capable of forming an organogel in nonpolar organic solvents and different types of nanostructures in other solvents. The state of the gel and the chirality of the nanostructures could both be adjusted by subsequent light irradiation at different wavelengths. The helical nanofiber-like morphology was verified in the internal structure of the gel. The performance of this gel was investigated by a series of methods, such as UV–vis absorption spectroscopy, circular dichroism, scanning electron microscopy and rheological techniques. This work provides a new method for facile synthesis of chiro-optical gels.