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Receptors 1
Published in James E. Ferrell, Systems Biology of Cell Signaling, 2021
This model predicts that activation maxes out at less than 100%, with the propensity of a ligand to induce the receptor to adopt its activated conformation being determined by K3, which could vary from ligand to ligand. This explains why some ligands act as full agonists—presumably the equilibrium in the K3 step very much favors the activated conformation—while other ligands act as partial agonists (promoting the conformation change more weakly) and still others act as antagonists, binding but not promoting activation at all. The µ-opioid receptor-binding drugs morphine, heroin, and fentanyl are all regarded as full agonists, with maximal binding leading to maximal receptor activation, whereas buprenorphine is a high-affinity partial agonist, with maximal binding causing less-than-maximal activation. For this reason, buprenorphine is sometimes used to treat opioid addiction; it can maintain an addict in a less-than-maximally intoxicated state that can allow the addict to function more normally. The high-affinity µ-opioid receptor-binding drugs naltrexone and naloxone function as antagonists, binding to receptors without promoting receptor activation. For this reason they can save the life of someone overdosing on an opioid agonist, competing with a death-inducing agonist for access to the receptor and thus decreasing receptor activity to levels compatible with life.
Transdermal delivery of buprenorphine from reduced graphene oxide laden hydrogel to treat osteoarthritis
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Ziqiang Zhang, Xiaogang Wang, Pengshan Li, Minghua Bai, Wenbing Qi
Transdermal delivery of buprenorphine is a noninvasive route to ensure constant and predictable serum drug levels over a prolong period of time to manage chronic pain [13, 14]. The transdermal route eliminate frequent dosing and provide reliable pain control, few adverse events and better patient outcomes [15, 16]. Talib et al. [17] prepared artemether laden chitosan-chondroitin nanoparticles for improved permeability via skin tissue. Takeuchi et al. [18] fabricated chitosan coated PLGA nanoparticles to deliver positively charges drugs via transdermal route by iontophoresis. The group also delivered cyclosporine laden nanoparticles to enhance skin permeability [19]. The drug laden nanoparticulate system showed potential advantage to improve the drug permeation across the skin tissue [20]. The nanoparticles are widely employed to deliver growth factors, genes, cartilage and other regenerative materials [21]. The objective of this paper was to fabricate a novel buprenorphine-loaded Pluronic F127-reduced graphene oxide transdermal hydrogel to control the release of buprenorphine for prolong analgesia in osteoarthritis.