Ketamine is a medication used in various medical settings, primarily recognized for its anesthetic properties. It induces a dissociative state, meaning it can make a person feel detached from their pain and surroundings. Beyond its use in anesthesia, ketamine is also employed for certain mental health conditions and chronic pain management. This article clarifies the components that make up different ketamine formulations.
The Active Ingredient: Ketamine Hydrochloride
The sole active pharmaceutical ingredient in ketamine formulations is ketamine hydrochloride. This substance is a white crystalline compound, chemically known as dl 2-(o-chlorophenyl)-2-(methylamino)cyclohexanone hydrochloride. It is responsible for all of ketamine’s therapeutic effects, including its ability to reduce pain perception, induce sedation, and create a dissociative anesthetic state. Ketamine hydrochloride is typically formulated as a slightly acidic sterile solution, with a pH range of 3.5 to 5.5, for intravenous or intramuscular injection.
Inactive Components and Their Roles
Pharmaceutical products contain more than just the primary drug; they also include inactive ingredients, often called excipients. These components do not directly exert therapeutic effects but serve various important functions in the medication’s overall stability, safety, and effectiveness. Excipients help ensure the drug remains stable over time, dissolves correctly, and can be administered safely and accurately.
General categories of excipients include solvents, which dissolve the active ingredient, and buffers, which help maintain a stable pH. Antimicrobial preservatives are also added to prevent the growth of bacteria, particularly in multi-dose formulations. While these ingredients are considered inert, some, like benzethonium chloride, have shown some pharmacological activity.
Ingredient Variations in Different Formulations
The specific inactive ingredients found in ketamine products can vary depending on the intended route of administration. For intravenous or intramuscular injections, formulations include sterile water for injection as the solvent. Sodium chloride may be added to achieve isotonicity, ensuring the solution is compatible with the body’s fluids and preventing irritation at the injection site. A preservative like benzethonium chloride is also present to maintain sterility in multi-dose vials.
Nasal spray formulations, such as esketamine nasal spray, also contain specific excipients tailored for nasal delivery. These may include citric acid monohydrate and sodium hydroxide to adjust and maintain a pH of around 4.5, along with water for injection. Oral formulations, which can include solutions or troches, require different inactive ingredients. These might involve binders and fillers to form tablets or lozenges, and flavorings or sweeteners like stevia to improve palatability. Polyethylene glycol (PEG) is used as a base in troches, while substances like silica gel act as suspending agents or desiccants.