Ketamine [BSA]

Ketamine, chemically known as (R,S)-ketamine, is a non-competitive N-methyl-D-aspartate receptor (NMDAR) antagonist that has been used as a clinical anesthetic for more than half a century. Ketamine has two enantiomers, (R)-ketamine and (S)-ketamine, which have significant differences in pharmacological activity. Its molecular structure contains a cyclic amino ketone structure that can effectively block the activity of NMDAR, thereby interfering with the process of neural transmission. This mechanism not only makes ketamine perform excellently in anesthesia but also reveals its potential advantages in the treatment of depression. In recent years, the discovery of ketamine as a fast-acting antidepressant has ushered in a new era of neuropsychiatric therapeutics, characterized by the onset of antidepressant responses within hours or days instead of weeks or months.

The application of ketamine in the treatment of major depressive disorder (MDD) and treatment-resistant depression (TRD) is considered a major breakthrough. Traditional antidepressants usually take weeks or even months to take effect, while ketamine can produce significant antidepressant effects within hours or days. Numerous clinical studies support the use of sub-anesthetic doses of ketamine and its (S)-enantiomer esketamine in treating various neuropsychiatric disorders, including depression, bipolar disorder, anxiety spectrum disorders, substance use disorders, eating disorders, and chronic pain. Ketamine not only effectively alleviates depressive symptoms but also improves symptoms related to various conditions, such as anxiety, anhedonia, and suicidal ideation. NMDAR is considered the primary pharmacological target of ketamine's antidepressant effects, as NMDAR is the binding target of low concentrations of ketamine.

Despite the significant therapeutic effects of ketamine in treating depression and in anesthesia, its psychoactive and dissociative properties as a dissociative anesthetic could lead to potential abuse. Long-term or excessive use of ketamine may cause psychological dissociation and other side effects, as well as the potential for dependence. While (R)-ketamine may not always be more successful than (S)-ketamine in treating depression, recent studies have shown that (R)-ketamine performs better in terms of adverse effects and misuse potential. It has been discovered that (R)-ketamine had fewer adverse effects and a more potent, longer-lasting antidepressant effect than (R,S)-and (S)-ketamine. Furthermore, mounting data points to the potential importance of (R)-ketamine in treating a variety of illnesses, including osteoporosis, multiple sclerosis, ischemic stroke, perioperative anesthesia, cognitive impairment, and Parkinson's disease. Although ketamine has a lot of promise for the medical field, its misuse potential and adverse consequences must be adequately addressed, and study and use should adhere to stronger legal and regulatory requirements.

Figure 1. Partial Mechanisms of (R)-ketamine Antidepressant (Source: Zhang S, et al , 2024)

Ketamine Bovine Serum Albumin
Ketamine Conjugated BSA
Ketamine-BSA Complex