Space Station-like Composite Nanoparticles for Co-Delivery of Multiple Natural Compounds from Chinese Medicine and Hydrogen in Combating Sensorineural Hearing Loss

A silk-based hydrogel containing dexamethasone and lipoic acid microcrystals for local delivery to the inner ear

Local drug delivery has been exploited recently to treat hearing loss, as this method can both bypass the blood-labyrinth barrier and provide sustained drug release. Combined drug microcrystals (MCs) offer additional advantages for sensorineural hearing loss treatment via intratympanic (IT) injection due to their shape effect and combination strategy. In this study, to endow viscous effects of hydrogels, nonspherical dexamethasone (DEX) and lipoic acid (LA) MCs were incorporated into silk fibroin (SF) hydrogels, which were subsequently administered to the tympanic cavity to investigate their pharmaceutical properties. First, we prepared DEX and LA MCs by a traditional precipitation technique followed by SF hydrogel incorporation (SF+DEX+LA). After characterization of the physicochemical features, including morphology, rheology, and dissolution, both a suspension of combined DEX and LA MCs (DEX+LA) and SF+DEX+LA were administered to guinea pigs by IT injection, after which the pharmacokinetics, biodegradation and biocompatibility were evaluated. To our surprise, compared to the DEX+LA group, the pharmacokinetics of the SF+DEX+LA hydrogel group did not improve significantly, which may be ascribed to their nonspherical shape and deposition effects of the drugs MCs. The cochlear tissue in each group displayed good morphology, with no obvious inflammatory reactions. This combined MC suspension has the clear advantages of no vehicle, easy scale-up preparation, and good biocompatibility and outcomes, which paves the way for practical treatment of hearing loss via local drug delivery.

Nanopharmacology as a new approach to treat neuroinflammatory disorders

Neuroinflammation, a complex process involving the activation of microglia, astrocytes, and other immune cells in the brain, plays a role in neurodegeneration and psychiatric disorders. Current therapeutic strategies for neuroinflammation are limited, necessitating the development of improved approaches. Nanopharmacology offers unprecedented opportunities to access and treat neuroinflammatory disorders at the brain level. Nanoscaffolds can target specific cells or tissues and protect drugs from degradation or elimination, making them ideal candidates for treating neurodegenerative and psychiatric diseases. Recent advancements in nanoparticle development have enabled the targeting of microglia, astrocytes, and other immune cells in the brain, reducing neuroinflammation and protecting neurons from injury. Nanoparticles targeting specific neurons have also been developed. Clinical trials are in progress to evaluate the safety and efficacy of nano drugs for treating neuroinflammatory, neurodegenerative, and psychiatric diseases. The successful development of these nanodrugs holds immense promise for treating these devastating and increasingly prevalent conditions. On the other hand, several limitations and unanswered questions remain. First, the long-term effects of nanoparticles on the brain need to be thoroughly investigated to ensure their safety. Second, optimizing the targeting and delivery of nanoparticles to specific brain regions remains a challenge. Understanding the complex interplay between nanoparticles and the brain's immune system is crucial for developing effective nanotherapies. Despite these limitations, nanopharmacology presents a transformative approach to treating neuroinflammatory disorders. Future research should address the aforementioned limitations and further elucidate the mechanisms of nanoparticle-mediated therapy. The successful development of safe and effective nanodrugs can revolutionize the treatment of neuroinflammatory disorders, alleviating the suffering of millions.