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Have you ever wondered why there are different methods to administer medications to the body?

The human body is a complex network of interacting systems, organs, tissues, and cells.  Medications are customized for delivery to the body via schemes dependant on the type of ailment they aim to treat.  Each delivery technique has its advantages and disadvantages.  Below, we provide a brief overview of the common medication methods available today, along with some new technological advances.

1) Oral Treatments

Comprising over 60% of the drug market, the most common forms of over-the-counter prescriptions are pills or liquid-form medications.  Available for almost every type of disorder, oral drugs are especially useful for sudden onset of symptoms, as experienced in migraine and pain conditions, nausea, allergies, and certain mental conditions like schizophrenia.  Swallowed, chewed, or placed under the tongue, these medicines act by being absorbed from the digestive tract into the bloodstream and then carried to all parts of the body.  A major disadvantage is that they are not specific and may adversely affect parts of the body not targeted for treatment.  The ease of dosage control, however, gives oral remedies the preferred status among most doctors and patients alike, despite the known issues with their delivery.  Current research in the field of oral medication centers on more exact dosage control, pulse-like release of the drugs, and reduction in dependency and abuse of pain medications.

2) Topical Treatments

These medications are most commonly used for disorders of the skin and mucous membranes like the eye, and inside of the mouth, vagina, and anus.  They treat a variety of conditions including eczema, dermatitis, psoriasis, acne, microbial and fungal infections, and also provide relief for mild pain caused by muscle and joint inflammations, arthritis, nerve damage, and burns.  Available as creams, gels, foams, sprays, powders, solutions, and even adhesive systems, these medications are easy to apply and are geared towards action on specific sites of the body.  Unlike oral medications that take longer to bypass metabolism of the digestive and circulatory system, topical drugs are quick-acting.  Disadvantages include possible allergic reactions and irritations.  Novel topical treatments are being developed for conditions such as diabetic foot and glaucoma.

3) Inhalant Medications

Therapeutic aerosols for various respiratory disorders, such as asthma, bronchitis, pneumonia, cystic fibrosis, allergies, and pulmonary hypertension have been available for years.  Like topical treatments, inhalation allows the drug to reach the specific location in the body faster than oral medications, bypassing the metabolism and cause less adverse effects to other areas of the body.  Some novel applications of aerosols comprise insulin for diabetics, opioids for pain and migraines, and treatments of bone disorders and cancer.

4) Injections

Injection medications are currently used largely for hormonal disorders, such as diabetes, where self-injection techniques have become the foundation of treatment.  Other common medical uses are for allergies, cosmetics, and pain management, due to convenient delivery of drugs through injection into the nervous system.  Three modes of injection exist: intravenous (into the blood vessel), subcutaneous (beneath the skin), and intramuscular (into muscle).  The most appropriate one is chosen depending on the location and speed required for drug action.

Research and development of injection therapies for autoimmune diseases, such as cancer, rheumatoid arthritis, Crohn’s disease, and Multiple Sclerosis are underway.  Vaccines, protein, and gene-based drugs are also first candidates for injection, as this method sidesteps degradation of drugs by enzymes.

 

Bhowmik, D. et al. Recent advances in novel topical drug delivery system.  Online Available: www.thepharmajournal.com Last accessed July 12, 2013.  Gan, L. et al.  Recent advances in topical ophthalmic drug delivery with lipid-based nanocarriers. Drug Discovery Today 18(5-6): 290-297 (2013).Injectable Drug Delivery Market by Formulations [Liposomes, Microspheres, & Nanoparticles], Devices [Disposables & Reusable, Fillable & Prefilled, Pen, Needle Free & Auto Injectors] & Therapeutics [Diabetes & Oncology] – Global Forecasts to 2017. Available online: http://www.marketsandmarkets.com/Market-Reports/injectable-drug-delivery-market-150.html. Last accessed: July 12, 2013.Papanas, N. et al.  Advances in the topical treatment of diabetic foot ulcers.  Current Diabetes Review 8(3):209-18 (2012).Rekhi, G. S. Advances in solid dose oral drug delivery. Elan Drug Technologies.  Available online: http://www.ondrugdelivery.com/publications/Oral%202010/Elan.pdf. Last accessed July 12, 2013.

Shaikh, S. et al. Recent advances in pulmonary drug delivery system: a review. International Journal of Applied Pharmaceutics 2(4): 27-31 (2010).

 

Written by Julia Yusupova

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