Journal of Pharmaceutics & Drug Delivery Research ISSN: 2325-9604

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Editorial, J Pharm Drug Deliv Res Vol: 1 Issue: 1

Prospect of 19F MRI-Guided Drug Delivery

Y. Bruce Yu1* and Zhong-Xing Jiang2
1Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201, USA
2School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
Corresponding author : Y. Bruce Yu
Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201, USA
E-mail: [email protected]
Received: September 21, 2012 Accepted: September 22, 2012 Published: September 24, 2012  doi:10.4172/2325-9604.1000e101
Citation: Y. Bruce Yu (2012) Prospect of 19F MRI-Guided Drug Delivery. J Pharm Drug Deliv Res 1:1. doi:10.4172/2325-9604.1000e101

Abstract

Prospect of 19F MRI-Guided Drug Delivery

Prescription drugs are tracked all the way from the manufacturerto the patient. But once a drug enters the patient’s body, we lose track of it. We do not know at any given time point, where the drug is, in what form, and how much. However, such information would very useful in optimizing drug therapy for each patient. This information is unlikely to be deducted from a patient’s DAN sequences (e.g.: single nucleotide polymorphisms). Butimage-guided drug delivery has the potential to gather such information.

Keywords: Drug interaction, Pharmacognosy

 
Prescription drugs are tracked all the way from the manufacturer to the patient. But once a drug enters the patient’s body, we lose track of it. We do not know at any given time point, where the drug is, in what form, and how much. However, such information would be very useful in optimizing drug therapy for each patient. This information is unlikely to be deduced from a patient’s DAN sequences (e.g., single nucleotide polymorphisms). But image-guided drug delivery has the potential to gather such information [1].
When the drug delivery process is monitored by an imaging technique, then it is possible to tailor drug dose and dosing schedule to suite each patient’s specific response. This is the case with the radioimmunotherapy drugBexxar®. Before Bexxar® is administered to the patient at the therapeutic dose level, it is given to the patient at a diagnostic dose level. After a few rounds of nuclear imaging which determine the biodistribution of the drug in the patient’s body, a decision is made as to whether the treatment should proceed and if yes, at what dose [2]. In the case of radiotherapeutics such as Bexxar®, imaging comes naturally. But for non-radioactive drugs, image-guided drug delivery requires to first make the drug visible to an imaging modality. Several options are available, such as nuclear, magnetic resonance and optical imaging. Here, we wish to point out that 19F MRI offers a unique opportunity to track therapeutic agents in vivo. Compared with nuclear imaging, no radioactivity is involved in 19F MRI. Compared with optical imaging, 19F MRI has no tissue depth limit. Compared with 1H MRI, 19F MRI has several advantages: lack of endogenous background interference; direct proportionality between 19F signal intensity and 19F imaging agent concentration; much wider chemical shift range, which makes it possible to use the 19F chemical shift to detect drug metabolism, as in the case of capecitabine [3].
From 1977, perfluorocarbons (PFCs) have been explored as 19F imaging agents [4]. But PFCs have many deficiencies as imaging agents, including split 19F signal in most cases, complex formulation procedure, and excessive and prolonged accumulation in liver and spleen. However, recent progresses based on fluorinated asymmetric dendrimers have overcome these problems [5]. Nonetheless, 19F MRI-guided drug delivery still faces considerable difficulties, mainly caused by the intrinsic low sensitivity MRI. Such low sensitivity requires a 19F imaging agent to contain a large number of fluorine atoms, which creates two problems. One is that their synthesis, especially large scale synthesis at economically feasible cost, can be very challenging. Another is that the large size of the imaging agent is likely to alter the PK/PD profile of the labeled drug. The first challenge requires breakthroughs in the synthesis of large fluorinated dendrimers. The second challenge requires proper integration of imaging and delivery technologies so that PK/PD alteration can actually be exploited to achieve better therapy outcome. Neither one is straightforward. But there appears now to be a resurge of interest in 19F MRI [6]. With concerted efforts from various disciplines, such as synthetic chemistry, drug delivery, and imaging technologies, it is our hope that rapid advances can be made in 19F MRI-guided drug delivery. With the development of multi-chromic 19F MRI techniques [7], it might eventually be possible to track several therapeutic agents simultaneously, each at its own “color” (radiofrequency).

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