Neurodegenerative disorders encompass a wide range of pathological conditions caused by progressive damage to the neuronal cells and nervous-system connections, which primarily target neuronal dysfunction and result in problems with mobility, cognition, coordination, sensation, and strength. Molecular insights have revealed that stress-related biochemical alterations such as abnormal protein aggregation, extensive generation of reactive oxygen and nitrogen species, mitochondrial dysfunction, and neuroinflammation may lead to damage to neuronal cells. Currently, no neurodegenerative disease is curable, and the available standard therapies can only provide symptomatic treatment and delay the progression of the disease. Interestingly, plant-derived bioactive compounds have drawn considerable attention due to their well-established medicinal properties, including anti-apoptotic, antioxidant, anti-inflammatory, anticancer, and antimicrobial properties, as well as neuroprotective, hepatoprotective, cardioprotective, and other health benefits. Plant-derived bioactive compounds have received far more attention in recent decades than synthetic bioactive compounds in the treatment of many diseases, including neurodegeneration. By selecting suitable plant-derived bioactive compounds and/or plant formulations, we can fine tune the standard therapies because the therapeutic efficacy of the drugs is greatly enhanced by combinations. A plethora of in vitro and in vivo studies have demonstrated plant-derived bioactive compounds’ immense potential, as proven by their capacity to influence the expression and activity of numerous proteins implicated in oxidative stress, neuroinflammation, apoptosis, and aggregation. Thus, this review mostly focuses on the antioxidant, anti-inflammatory, anti-aggregation, anti-cholinesterase, and anti-apoptotic properties of several plant formulations and plant-derived bioactive compounds and their molecular mechanisms against neurodegenerative disorders.

Chronic ocular diseases can seriously impact the eyes and could potentially result in blindness or serious vision loss. According to the most recent data from the WHO, there are more than 2 billion visually impaired people in the world. Therefore, it is pivotal to develop more sophisticated, long-acting drug delivery systems/devices to treat chronic eye conditions. This review covers several drug delivery nanocarriers that can control chronic eye disorders non-invasively. However, most of the developed nanocarriers are still in preclinical or clinical stages. Long-acting drug delivery systems, such as inserts and implants, constitute the majority of the clinically used methods for the treatment of chronic eye diseases due to their steady state release, persistent therapeutic activity, and ability to bypass most ocular barriers. However, implants are considered invasive drug delivery technologies, especially those that are nonbiodegradable. Furthermore, in vitro characterization approaches, although useful, are limited in mimicking or truly representing the in vivo environment. This review focuses on long-acting drug delivery systems (LADDS), particularly implantable drug delivery systems (IDDS), their formulation, methods of characterization, and clinical application for the treatment of eye diseases.

The first conductive polymers (CPs) were developed during the 1970s as a unique class of organic substances with properties that are electrically and optically comparable to those of inorganic semiconductors and metals while also exhibiting the desirable traits of conventional polymers. CPs have become a subject of intensive research due to their exceptional qualities, such as high mechanical and optical properties, tunable electrical characteristics, ease of synthesis and fabrication, and higher environmental stability than traditional inorganic materials. Although conducting polymers have several limitations in their pure state, coupling with other materials helps overcome these drawbacks. Owing to the fact that various types of tissues are responsive to stimuli and electrical fields has made these smart biomaterials attractive for a range of medical and biological applications. For various applications, including the delivery of drugs, biosensors, biomedical implants, and tissue engineering, electrical CPs and composites have attracted significant interest in both research and industry. These bimodalities can be programmed to respond to both internal and external stimuli. Additionally, these smart biomaterials have the ability to deliver drugs in various concentrations and at an extensive range. This review briefly discusses the commonly used CPs, composites, and their synthesis processes. Further highlights the importance of these materials in drug delivery along with their applicability in various delivery systems.