A codrug or "mutual prodrug" consists of two synergistic drugs chemically linked together to a ''single molecule'', in order to improve the drug delivery properties of one or both drugs. An effective codrug should be pharmacologically inactive in its own right but should release the constituent drugs upon biochemical breakage of the chemical linkage at the target tissue where their therapeutic effects are needed. As such, the chemical linkage (usually a covalent bond) should be subjectable to biodegradation, such as hydrolysis, by an enzymatic or non-enzymatic mechanism. The differential distribution of enzymes capable of catalyzing the breakage of the chemical linkage in different tissues may be exploited to achieve tissue-specific metabolism of the codrug to release the constituent drugs. The constituent drugs are indicated for the same disease but may exert different therapeutic effects via disparate mechanisms of action.

Motivation

Development of Anticancer Codrugs The disadvantages associated with the co-delivery of physically combined chemotherapeutic drugs/agents often suffer from poor solubility, less membrane permeability, unimproved bioavailability, as well as poor selectivity for the targeted cells. Simply we can say that physically combine drugs always struggles with less improved pharmacokinetic properties. Where selectivity is a major issue in the complex environment of a targeted cell. Several codrugs reported in the literature for the anticancer drug delivery with improved pharmacokinetic properties may provide ideas to the pharmaceutical scientist for further drug development in various diseases. ''Codrug of butyric acid and ATRA,'' Codrug of ATRA and histone deacetylase inhibitors, ''5-Fluorouracil (5-FU) and cytarabine (Ara-C) codrug,'' ''Paclitaxel and captopril codrug,'' ''5-Fluorouracil and diazeniumdiolate codrug,''

Common codrugs

Benorylate Benorilate (INN), or benorylate, is an ester-linked codrug of aspirin with paracetamol. It is used as an anti-inflammatory and antipyretic medication. In the treatment of childhood fever, it has been shown to be inferior to paracetamol and aspir ...

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ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

ified

paracetamol Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. Common brand names include Tylenol and Panadol. At a standard dose, paracetamol only slightly decreases body temperature; it is inferi ...

and

acetylsalicylic acid Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat in ...

Fenethylline Fenethylline ( BAN, USAN) is a codrug of amphetamine and theophylline and a prodrug to both. It is also spelled phenethylline and fenetylline (INN); other names for it are amphetaminoethyltheophylline and amfetyline. The drug was marketed for ...

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amphetamine Amphetamine (contracted from alpha- methylphenethylamine) is a strong central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. It is also commonly used ...

chemically linked with

theophylline Theophylline, also known as 1,3-dimethylxanthine, is a phosphodiesterase inhibiting drug used in therapy for respiratory diseases such as chronic obstructive pulmonary disease (COPD) and asthma under a variety of brand names. As a member of the ...

* Lisdexamfetamine — a

substituted amphetamine Substituted amphetamines are a class of compounds based upon the amphetamine structure; it includes all derivative compounds which are formed by replacing, or substituting, one or more hydrogen atoms in the amphetamine core structure with s ...

with an

amide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it is ...

linkage formed by the

condensation Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor ...

dextroamphetamine Dextroamphetamine is a central nervous system (CNS) stimulant and an amphetamine enantiomer that is prescribed for the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. It is also used as an athletic performance and ...

with the

carboxylate group In organic chemistry, a carboxylate is the conjugate base of a carboxylic acid, (or ). It is an ion with negative charge. Carboxylate salts are salts that have the general formula , where M is a metal and ''n'' is 1, 2,...; ''carboxyla ...

of the

essential amino acid An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life form ...

L-lysine. *

Sulfasalazine Sulfasalazine, sold under the brand name Azulfidine among others, is a medication used to treat rheumatoid arthritis, ulcerative colitis, and Crohn's disease. It is considered by some to be a first-line treatment in rheumatoid arthritis. It is ...

— sulfapyridine chemically linked to

5-aminosalicylic acid Mesalazine, also known as mesalamine or 5-aminosalicylic acid (5-ASA), is a medication used to treat inflammatory bowel disease, including ulcerative colitis and Crohn's disease. It is generally used for mildly to moderately severe disease. It ...

coupled with an azo linkage. It is on the

World Health Organization's List of Essential Medicines The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health s ...

. *

Sultamicillin Sultamicillin, sold under the brand name Unasyn among others, is an oral form of the penicillin antibiotic combination ampicillin/sulbactam. It is used for the treatment of bacterial infections of the upper and lower respiratory tract, the kidneys ...

—

ified

ampicillin/sulbactam Ampicillin/sulbactam is a fixed-dose combination medication of the common penicillin-derived antibiotic ampicillin and sulbactam, an Enzyme inhibitor, inhibitor of bacterial beta-lactamase. Two different forms of the drug exist. The first, develo ...

References

* {{Pharm-stub