Injectable supersaturated acetaminophen solution for spinal administration

Abstract

The present invention relates to an acetaminophen injectable aqueous solution for use in the treatment or in the prevention of pain by spinal administration, wherein said acetaminophen injectable solution is supersaturated. In certain embodiments, the acetaminophen injectable aqueous solution is administered simultaneously, separately or sequentially with a local anaesthetic by spinal administration.

Description

FIELD OF THE INVENTION[0001]The present invention relates to an acetaminophen injectable solution for spinal administration.[0002]The present invention originates from the field of drugs in liquid form suitable for spinal administration.[0003]More specifically, the present invention relates to an injectable pharmaceutical formulation containing acetaminophen as active ingredient for the treatment of post-surgical pain by spinal administration.PRIOR ART[0004]Acetaminophen (acetyl-p-aminophenol), commonly known as paracetamol (CAS no: 103-90-2), is an active ingredient possessing analgesic and antipyretic activity used widely in medical practice to alleviate acute and chronic pain and to reduce the body temperature when this exceeds physiological values.[0005]Paracetamol, conversely to the majority of commonly used analgesic drugs, is not an NSAID (non-steroidal anti-inflammatory drug), since it is almost devoid of antiaggregant and anti-inflammatory activity. To date, its mechanism o...

AI Technical Summary

Benefits of technology

[0025]The inventors have discovered that, by means of spinal administration of an acetaminophen supersaturated injectable aqueous solution, it is possible to obtain an effective analgesic effect of unexpectedly prolonged duration, typically equal to or greater than 24 hours. In particular, the spinal administration of an acetaminophen supersaturated solution according to the invention results in effective analgesia for at least 24 hours in mice and in rats in the case of inflammatory pain induced by carrageenan and in post-surgical pain.

[0038]The acetaminophen supersaturated solution obtained with the process according to the invention is highly stable, has an increased concentration of acetaminophen in the solvent, and can be mixed with a solution of a conventional local anaesthetic in order to obtain a solution with a total volume that is compatible with the volume injectable by means of spinal administration in a single administration process.

Problems solved by technology

Administration of acetaminophen by means of methods alternative to traditional methods is still yet to be explored extensively, and essentially no specific applications have been found in the field of analgesic therapy.

During the spinal injection, the risks of causing neurological damage are limited by the fact that the spinal column is protected by the pia mater, the innermost of the meningeal membranes.

During the infusion process, the solution containing the local anaesthetic mixes with the cerebrospinal fluid, thus blocking conduction via the nervous system of impulses to the brain and causing a reversible loss of sensitivity, which may be accompanied by motor paralysis.

Both of these therapeutic approaches not only expose patients to a series of possible side effects varying in accordance with the type and quantity of drug administered, but also, in many cases, do not provide a suitable analgesic response.

Images