OxyContin is made of oxycodone hydrochloride, a semi-synthetic opioid, embedded in a matrix of inactive ingredients designed to release the drug slowly over 12 hours. The active ingredient originates from the opium poppy plant, while the tablet itself is engineered with specific polymers that control how quickly your body absorbs it.
The Active Ingredient: Oxycodone
The drug in OxyContin is oxycodone hydrochloride, an opioid that works by binding to pain receptors in the brain and spinal cord. Its chemical formula is C18H21NO4·ClH. Oxycodone is classified as a semi-synthetic opioid, meaning it starts with a natural compound from the opium poppy and is then chemically modified in a lab.
The natural starting point is thebaine, one of several alkaloids found in opium poppies. Unlike morphine or codeine, thebaine isn’t used directly as a painkiller. Instead, it serves as a chemical building block. Pharmaceutical manufacturers farm opium poppies, isolate thebaine from the plant material, and then run it through a series of chemical transformations to produce oxycodone. These steps add a hydroxyl group (an oxygen-hydrogen pair) at a specific position on the molecule, which changes how it interacts with the body’s opioid receptors. The final product is more potent than codeine and has distinct absorption characteristics that make it suitable for extended-release formulations.
The Tablet Matrix: How It’s Built
What makes OxyContin different from immediate-release oxycodone isn’t the drug itself. It’s the tablet surrounding it. OxyContin uses a dual-polymer matrix to control delivery, releasing oxycodone gradually over a 12-hour window rather than all at once.
The core inactive ingredients shared across all tablet strengths (10 mg through 80 mg) are:
- Polyethylene oxide: the primary matrix polymer that controls how fast the tablet erodes and releases oxycodone
- Magnesium stearate: a lubricant that helps the tablet hold together and move through manufacturing equipment
- Hypromellose: a cellulose-based polymer used in the film coating
- Polyethylene glycol 400: a plasticizer that keeps the coating flexible
- Butylated hydroxytoluene (BHT): an antioxidant that prevents the drug from degrading over time
- Titanium dioxide: a white pigment used in the base coating
Individual tablet strengths contain additional coloring agents. Iron oxides in various combinations produce the gray, pink, brown, yellow, red, and green colors that distinguish different doses. The 80 mg tablet, for example, uses yellow iron oxide plus an indigo dye to achieve its green color. These pigments serve a practical purpose: they let pharmacists and patients quickly identify the correct dose by sight.
How the Controlled-Release System Works
When you swallow an OxyContin tablet, it encounters fluid in your digestive tract and begins to erode slowly. The polyethylene oxide matrix swells and forms a gel-like layer on the tablet’s surface. This gel acts as a barrier, forcing the oxycodone to seep out gradually rather than flooding your bloodstream. As the outer layer erodes, a new gel layer forms underneath, maintaining a steady release rate for roughly 12 hours.
This is why the tablets must be swallowed whole. Breaking, crushing, or chewing the tablet destroys the matrix structure and can release the entire dose at once, which is dangerous because even a single tablet may contain enough oxycodone for 12 hours of pain relief delivered all at once.
The Abuse-Deterrent Reformulation
The OxyContin sold today is not the same formulation that originally hit the market. In April 2010, the FDA approved a reformulated version specifically designed to be harder to misuse. The original tablets could be crushed into a fine powder and then snorted or dissolved and injected. The reformulated version uses polyethylene oxide in a way that resists these methods.
When someone tries to crush the current tablet, it doesn’t break into fine powder. Instead, it produces large, chunky fragments that are difficult to snort. If those fragments are mixed with water or another liquid, the polyethylene oxide swells into a thick, viscous gel rather than dissolving into a solution. This makes it essentially impossible to draw through a syringe for injection.
The FDA reviewed postmarketing data and clinical studies before allowing Purdue Pharma to add abuse-deterrent labeling in 2013. The agency concluded that the reformulation could be expected to significantly reduce abuse through injection and snorting. The physicochemical properties of the new matrix made those routes of misuse far less practical, and clinical studies showed reduced “liking” when the reformulated product was taken in ways other than swallowing it whole.
Available Strengths and Identification
OxyContin comes in seven strengths: 10 mg, 15 mg, 20 mg, 30 mg, 40 mg, 60 mg, and 80 mg. All are round, film-coated tablets stamped with “OP” on one side and the milligram number on the other. Each strength has a distinct color:
- 10 mg: white
- 15 mg: gray
- 20 mg: pink
- 30 mg: brown
- 40 mg: yellow
- 60 mg: red
- 80 mg: green
The color coding is consistent across manufacturers and is one of the quickest ways to confirm you have the correct dose. If a tablet’s color doesn’t match the strength printed on it, that’s a red flag worth bringing to your pharmacist.