unbound drug

Free drug Therapeutics The fraction of drug in serum that is not bound to a carrier protein or other molecule, which generally is pharmacologically active

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Zolpidem-induced macropsia has been reported in women with anorexia.7 The protein-binding capacity of zolpidem is approximately 92%, mainly to albumin (66%) and al-acid glycoprotein (56.6%).4 In malnourished patients with anorexia nervosa, hypoalbuminemia is common and, therefore, unbound drug concentration is higher.

Zolpidem may cause visual distortions and other psychotic symptoms

The unbound drug may cause pharmacological activities or initiate side effects in the body [16-18].

Radiolabeling and Bioevaluation of Dextran Cysteamine Mannose for Sentinel Lymph Node Detection

Only the unbound drug--two per cent--can be filtered, so clearance by filtration is reduced, in comparison to an unbound drug. (2)

Metabolism and excretion: eliminating drugs from the body

Higher levels of unbound drug may exist due to hypoalbuminemia, competition for protein binding sites by uremic substances, and alterations in protein binding sites.

Medication considerations for patients with chronic kidney disease who are not yet on dialysis

Because only unbound drug is pharmacologically active, it is useful to measure the free concentration when any of the above conditions are present.

Prodrug metabolites: implications for therapeutic drug monitoring

The common laboratory practice is to measure total phenytoin concentrations, which assumes that phenytoin protein binding is relatively constant, so that the concentration of the active unbound drug can be predicted from the total drug plasma concentration (2,3).

Evidence-based implementation of free phenytoin therapeutic drug monitoring

Disopyramide Monitor unbound drug concentrations in renal failure patients.

Standards of laboratory practice: cardiac drug monitoring

where r is the number of moles of bound drug per protein molecule; [[D.sub.b]] and [[D.sub.f]] are the bound and unbound drug concentrations, respectively; [[P.sub.t]] is the total protein concentration; and [K.sub.i] and [N.sub.i] are the binding constant and the number of binding sites for the ith class of binding sites, respectively.

Effects of uremic toxins and fatty acids on serum protein binding of furosemide: possible mechanism of the binding defect in uremia

So, for drugs that are highly protein bound (e.g., phenytoin, which is an anti-seizure medication), there may be more unbound drugs available in infants as compared to older patients when the same dosages are given.

Pediatric medication dosing

SurModics' technology can provide a covalently bound crosslinked polymeric matrix on the surface of medical devices for use as a reservoir to incorporate unbound drugs. Therapeutic or antimicrobial agents can then be released from the matrix at a controlled rate.

Drug elution from medical device surfaces. (SurModics, Inc.: solutions in medical manufacturing)

1, 1990 CANCER RESEARCH that two LDL-bound injected drugs -- methotrexate and floxuridine -- successfully dodged the body's natural clearance mechanisms to circulate at least six times longer in the blood of rats than did unbound drugs. Because the LDLs survived longer than the drugs they had been carrying, de Smidt and van Berkel say the drugs may not have been chemically bound to the LDLs firmly enough.

The seeds of better chemotherapy?

As unbound drugs are removed from the plasma (either by elimination or crossing into another body compartment), bound drug molecules will be released from the plasma proteins.