UNM College of Pharmacy Lighting Up Science
In basement laboratories in the UNM School of Pharmacy, small imaging machines with narrow tubes take detailed pictures of mice, rats and ferrets that have been shot through with radioactive tracers.
The multi-million-dollar single photon emission computed tomography scanners are being used in radiopharmaceutical research on small animals to answer questions that are important to human health.
- Is this cancer drug targeting the right cells?
- Can we locate infection to quickly diagnose appendicitis?
- Exactly what part of the lung does this particular asthma drug reach?
Along with a robust research menu that aims to improve the next generation of radiopharmaceuticals, pharmacy students also get real-world experience in preparing radiotracers in an active, commercial nuclear pharmacy.
It is a modern extension of a story that began here four decades ago when the University of New Mexico’s pharmacy college began teaching radiopharmacy and established the first commercial radiopharmacy in the world.
Radiopharmacy was born at UNM
While a small number of universities were running experiments in nuclear medicine in the 1960s, there was great variability in the field. In the early 1970s, then-Dean Carmen Bliss gave new faculty member Richard Keesee the green light to follow his hunch that pharmacy was the answer to standardizing the radioactive isotopes used in nuclear medicine.
“Richard had the idea that if you wanted to standardize these radiotracers, pharmacy could really help,” says Jeffrey Norenberg, director of radiopharmaceutical sciences at UNM. “He had this idea that there was some economy of scale and product uniformity that could be achievable through the practice of pharmacy.”
In 1972, UNM’s on-campus nuclear pharmacy opened for business – the only licensed nuclear pharmacy in the world. Those early faculty members developed a pharmacy business that prepared and delivered safe and standardized doses of nuclear medicines.
In addition to supplying radiotracers for bone scans, heart scans and other medical tests to hundreds of clinics and hospitals throughout New Mexico and neighboring states, the pharmacy also trained the first generation of nuclear pharmacy students.
“By the second or third year,” Norenberg says, “all the students who were coming through this program were going out and starting their own pharmacies. It was the birth of an industry.”
Scott Burchiel, now a senior associate dean at the College of Pharmacy, arrived in 1978 when the nuclear pharmacy was only a few years old.
Burchiel helped create Summa Medical, the first pharmaceutical technology company in New Mexico and a precursor to the burgeoning tech-transfer field in higher education. Along with William Hladik and others, he helped to develop the radiopharmacy curriculum.
“What are we really known for? For many years we trained most of the people in the United States who work in the field,” Burchiel says. “We basically created a field.”
With a changing financial landscape in the nuclear pharmacy business, the pharmacy closed in 1992. It reopened under Dean Lynda Welage two years ago, bringing the College of Pharmacy squarely back in the business of radiopharmacy.
Today, UNM is one of only a few pharmacy schools that offer radiopharmacy education and training, has an active research arm and offers students practical experience in the on-campus pharmacy that once again fills orders and prepares doses for customers in Albuquerque.
“We want to be in control of our own hands-on training,” Norenberg says. “We want to do research. And we want to provide the best quality of radiopharmaceuticals to the people of Albuquerque.”
At its most basic level, nuclear imaging involves using a small amount of radioactive material to identify disease or abnormalities in the body. The radiotracer is injected, inhaled or swallowed. As it accumulates in the area being investigated, it gives off electromagnetic energy, which is detected by a specialized camera. An imaging machine gives physicians detailed pictures, often in three dimensions, of organs, tissue or bones.
The radioactive isotope is the basis of the radiopharmacist’s work. Because isotopes commonly used in tracers have a half-life of a few hours and because most tests are conducted during daytime clinic hours, much of the work occurs early in the morning.
“The pharmacist is the one who gets up at 4 o’clock in the morning and comes in and prepares the radiotracers. They really have to be prepared fresh,” Burchiel explains. “There may be dozens of different preparations. You want a bone scan? A heart scan? A thyroid scan? Are you doing imaging or therapy? We prepare the doses under the sterile and pyrogen-free conditions. And run quality control reactions.”
While students in training under licensed radiopharmacists fill orders, the radiopharmacy program today also concentrates much of its efforts in the lab.
Norenberg directs the Keck-UNM Small-Animal Imaging Resource, which is a shared resource supported by the UNM Comprehensive Cancer Center, the Clinical and Translational Science Center and the College of Pharmacy. Funded by a grant from the W.M. Keck Foundation, the research lab facilitates PET, SPECT and CT imaging of small animals.
Its machines are scaled-down versions of the scanners humans might lie inside to be checked for clogged coronary arteries, for example. They can run the same clinical tests in small animals as the larger machines do in humans.
Just as in human tests, these scans aid researchers trying to identify unique signals of diseases and in identifying a ligand – a molecule that affects a targeted receptor’s behavior. When they make that ligand radioactive and inject it, it goes to the target and the PET or SPECT scan can then produce a detailed image.
“If we suspect a cancer,” Norenberg says, “we can inject a ligand that might be selectively taken up and retained by those cells and that will light up.”
Unlike other scanning technology, nuclear imaging gives a more finely detailed picture of tissue, providing much more information.
Radiopharmacy research aims to find solutions for diagnosing and treating disease.
As in much of science, the animal studies are a tool toward better outcomes in humans. Using a similar machine, or what Norenberg calls “translational imaging capability,” allows for a seamless translation of the science.
Drug companies, for example, want to know where their asthma drugs in development actually go once a patient inhales them.
Norenberg’s lab developed an animal model that started with mice. The mice got a radio-labeled aerosol and then their lungs were scanned. Researchers could see whether the drug stopped in the airway or got deep into the lung. In the lung, did it remain in the center or move to the edges?
After mice they moved up to larger lungs: rats, then ferrets, then rabbits, then dogs, then people.
The results were published in the Journal of Aerosol Medicine to help other drug formulators.
“I’m excited that we can visualize drug delivery and drug action in a noninvasive way,” Norenberg says. “We can actually see where that drug is going in their lung and we can start to imagine how we could look at outcomes. If you’re trying to treat somebody with chronic asthma, you’ve got to get that drug to the tissues that are affected. And we have a way to measure that now. We have a way that could improve drug delivery. So I think that’s very exciting.”
Norenberg’s lab has also developed a radiotracer that finds a specific protein in metastatic colorectal cancer – the GCC protein – that can be used to determine a tumor’s size and extent before a patient receives drug that targets that protein.
He also has several patents on radiotracer technology that locates inflammation, which he hopes might be used for better diagnosis of appendicitis, for example.
Radiopharmacy techniques can also help the pharmaceutical industry make better-informed decisions on drug development.
“We can help them get to the go/no go decision earlier,” Norenberg says. “And we can do that for them at a fraction of the cost. If a drug isn’t reaching its target, we can show that. We’re helping them kill projects that won’t be successful much earlier.”
Radiopharmacy represents a unique toolbox for asking and and answering questions that are important to human health, Norenberg says.
“We can do it in ways that are non-invasive, that allow us to look at the whole body, that can be repeated numerous times,” he says.” I think there’s tremendous power in that sort of application of this technology.”