What are Drug Carriers?

Mary McMahon
Mary McMahon

Drug carriers are compounds people can attach to drug molecules for targeted delivery, increased efficiency, or controlled release. Many can also act as buffers to reduce the toxic effects of medications. These include synthetic and natural compounds from a variety of sources, ranging from lipids to nanoparticles. Drug companies work on drug carrier development to provide themselves with an array of products they can use with their pharmaceuticals.

Drug carriers are compounds attached to drug molecules for targeted delivery or increased efficiency.
Drug carriers are compounds attached to drug molecules for targeted delivery or increased efficiency.

When patients take medications, they do not take a pure form of the active ingredient. Medications come with fillings and coatings to adjust the method of drug delivery. These compounds can also change the way the drug acts in the body. The drug carriers determine where the drug travels and how it behaves when it gets there.

Drug carriers often include coatings and fillings of medicines.
Drug carriers often include coatings and fillings of medicines.

A common example is a controlled release coating. This limits the release of the drug into the body, allowing a doctor to deliver a dose slowly over time, rather than all at once. Drug carriers can also resist stomach acid to make sure a drug will be able to reach the intestines, where the mucus membranes can absorb the medication. Other drug carriers may attach to the drug molecules to make sure they only target certain kinds of cells, like cancer cells or bacteria.

Drug carriers may contain buffers to prevent medications from damaging body tissue. Many drugs are toxic, and the toxic effects must balance with the therapeutic ones for the drug to be effective. A buffer can allow a patient to take a drug safely while making sure it still gets where it needs to go. The molecules used as drug carriers can also determine where a medication goes. Drugs that must pass the blood-brain barrier, for example, need to be on very small molecules or they will not be able to penetrate the brain tissue.

In the process of developing a drug carrier, companies look at how it acts in the body on its own before combining it with medications. One concern is the possibility of building up a store of a drug carrier because the body does not know how to eliminate it. This could potentially cause health problems for the patient over time.

Some drug carriers are proprietary. Drug companies use these in drug development to come up with novel ways of providing drug delivery to patients, and they protect them as trade secrets. Once a patent expires, any company can replicate the method and use it with its own medications. Others are freely and openly available, and anyone can use them to compound and develop new drugs.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


The remarks of anon 352751 could have been written by me, as I have had exactly the same history and over 42 years have only taken Paracetamol and very recently Warfarin without any sensitivity.

I have also felt I was going mad and I think even my family have found it hard to believe my continuous problems. As I was a GP's receptionist for 25 years, I understand that it is the carrier part of the medication that causes many bad side effects and I have had wonderful support from pharmacists getting me the best tablets for me, but then the carriers are changed with no information and problems re-occur. It is awful that " the cure" is worse than the condition and we are helpless and mostly misunderstood.


I have been ultra sensitive to almost every type of medication I have been prescribed to the point I have thought I was going mad. I have always had the idea that the carrier part of the drug has been to blame and did prove that to be true by eliminating a certain carrier in my hypertension medication (switching to another brand with help from my pharmacist). I had been very troubled with arrythmia but it stopped on switching manufacturers. Unfortunately, the drug company altered the ingredients (carrier part) and I am back to square one.


Am I the only one that finds the concept of a drug carrier being proprietary a bit scary? I understand that these companies spend a lot of money on research, but are the ideas behind drug encapsulation so novel at this point that they have to go to all that trouble to hide what they are doing? It makes me wonder what else may be going on with the drug that they are not saying under the guise of it being proprietary.


@danette1007-I was reading an article the other day about the use of liposomes as drug carriers in relation to insulin, but that was about developing an oral insulin medication. Whether it is an inhaled drug or an oral one I imagine that anything would be better than shots every day. I have to wonder if better and more comfortable ways of treating diabetes might not help a lot of people live longer and healthier lives. The article did mention that research suggested that inhaled insulin might be a lot more effective than oral.


My mother is diabetic and her doctor recently told her about a new form of insulin that researchers are working on. He mentioned drug carriers, but in this case it is a nasal drug delivery, not a coating or anything like that. From the way he described it she would not have to do insulin shots anymore, she could take it in an inhaled form, almost like an asthma inhaler. Naturally she is very excited about this, she really hates the needles. Does anyone know how far along they are in the research on this product and when it might be available for use for diabetic patients?

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