Chemistry: analytical and immunological testing – Lipids – triglycerides – cholesterol – or lipoproteins
Reexamination Certificate
2001-02-21
2003-04-01
Warden, Jill (Department: 1743)
Chemistry: analytical and immunological testing
Lipids, triglycerides, cholesterol, or lipoproteins
C436S101000, C436S173000, C436S139000
Reexamination Certificate
active
06541263
ABSTRACT:
1. INTRODUCTION
The invention is directed to methods for quantitatively determining the presence and/or amount of a corticosteroid in a solution by forming a corticosteroid-acetate adduct and detecting the adduct using a micromass LC/MS/MS system. These methods accurately detect trace amounts of corticosteroids. Optionally, these methods further detect other drug agents present in concentrations much greater than the corticosteroids to be detected. Preferably, the methods are used to substantially simultaneously detect and determine the amount of dexamethasone and other compounds such as bupivacaine within human plasma.
2. BACKGROUND OF THE INVENTION
The quick and accurate determination of drugs within human plasma is of paramount importance in many medical applications. Methods that accurately and quickly determine even trace amounts of a drug in the bloodstream are particularly useful. Moreover, these detection methods become of particular importance in the use of high potency drugs because unwanted side effects are produced when safe dosage levels are exceeded. Potent drugs can include, for example, glucocorticoids which can exacerbate neuronal damage due to hypoxia, ischemia, seizure, and hypoglycemia. Consequently, research has focused on developing drug detection and/or quantification methods that concurrently analyze samples such as plasma for a variety of compounds in differing amounts. This research, however, has been hampered because detection readings can be misinterpreted when the drugs to be detected are structurally similar to other compounds within the sample and/or the drugs are present in minute concentrations within the sample.
2.1 Corticosteroids
The effects of corticosteroids are numerous and widespread. Their diverse effects include: alterations in carbohydrate, protein, and lipid metabolism; maintenance of fluid and electrolyte balance; and preservation of normal function of the cardiovascular system, the immune system, the kidney, skeletal muscle, the endocrine system, and the nervous system. In addition, by mechanisms that are still not fully understood, corticosteroids provide the organism with the capacity to combat stressful circumstances such as noxious stimuli and environmental changes. For example, in the absence of the adrenal cortex, survival is made possible only by maintaining an optimal environment, including adequate and regular feedings, ingestion of relatively large amounts of sodium chloride, and maintenance of an appropriate environmental temperature.
The actions of corticosteroids are related in complex ways to those of other hormones. For example, in the absence of lipolytic hormones, cortisol has virtually no effect on the rate of lipolysis by adipocytes. Likewise, in the absence of glucocorticoids, epinephrine and norepinephrine have only minor effects on lipolysis. Administration of a small dose of a glucocorticoid, however, markedly potentiates the lipolytic action of these amines. These effects of corticosteroids that involve concerted actions with other hormonal regulators are termed permissive and most likely reflect steroid-induced changes in protein synthesis that, in turn, modify tissue responsiveness.
Corticosteroids include glucocorticoids and mineralocorticoids, including, but not limited to, aldosterone, beclomethasone, betamethasone, corticosterone, cortisol, cortisone, dexamethasone, fludrocortisone, flumethasone, hydrocortisone, 6&agr;-methylprednisolone, 6&bgr;-methylprednisolone, paramethasone, prednisolone, prednisone, prednylidene, 4-pregnene-20,21-diol-3,11-diol, presesterone, testosterone, triamcinolone, among others.
Two categories of toxic effects result from the therapeutic use of corticosteroids: those resulting from withdrawal of steroid therapy and those resulting from continued used of supraphysiological doses. There are several complications associated with steroid withdrawal, including acute adrenal insufficiency, resulting from too rapid withdrawal of corticosteroids after prolonged therapy, where the hypothalamic-pituitary-adrenal (HPA) axis has been suppressed. Besides the consequences that result from the suppression of the HPA axis, there are a number of other complications that result from prolonged therapy with corticosteroids. These include fluid and electrolyte abnormalities, hypertension, hyperglycemia, increased susceptibility to infection, osteoporosis, myopathy, behavioral disturbances, cataracts, growth arrest, and the characteristic habitus of steroid overdose including fat redistribution, striae, ecchymoses, acne, and hirsutism.
Traditionally, detection methods of corticosteroids have been limited by the inability to detect amounts lower than 100 pg/ml, interference by other compounds including other corticosteroids, extensive and tedious sample preparation, derivatization of samples prior to analysis, or a combination these limitations.
2.2 Dexamethasone
Dexamethasone possesses glucocorticoid activity and is especially used as an anti-inflammatory and anti-allergic drug. Topically, it is employed in the treatment of glucocorticoid-responsive dermatoses. Systemically, dexamethasone decreases the incidence and severity of hearing loss consequent to bacterial meningitis. Its systemic glucocorticoid potency is about 25 times that of cortisone. Dexamethasone is capable of inducing all the usual side effects of adrenal corticoids, except that the mineralocorticoid-like side effects are less pronounced than with cortisone acetate.
Also, glucocorticoids as a group are the most useful class of drugs for treating many eosinophil-related disorders. Glucocorticoids, e.g., dexamethasone, methylprednisolone and hydrocortisone, produce eosinopenia in normal persons, decrease circulating eosinophils in patients with eosinophilia, and reduce eosinophil influx at inflammatory sites (Butterfield et al., Anti-inflammatory Steroid Action: Basic and Clinical Aspects, Schleimer et al., eds., Academic Press, Inc., (1989) at page 151). In 1991, Wallen et al. (
J. Immunol.,
147, 3940 (1991)) reported the dose-dependent inhibition of IL-5-mediated eosinophil survival by dexamethasone, methylprednisolone and hydrocortisone. Moreover, they disclosed that dexamethasone produced a dose-dependent increase in the EC
50
for IL-5-mediated viability enhancement. The relative eosinophil viability inhibitory potencies of the glucocorticoids tested correlated with previously described anti-inflammatory potencies and with the affinities of these agents for the glucocorticoid receptor in the following order: dexamethasone>methylprednisolone>hydrocortisone.
2.3 Bupivacaine
Bupivacaine was introduced in 1963, and is a widely used amide local anesthetic; its structure is similar to that of lidocaine, except the amine-containing group is a butyl piperidine. It is a potent agent capable of producing prolonged anesthesia. Its long duration of action plus its tendency to provide more sensory than motor block has made it a popular drug for providing prolonged analgesia during labor or postoperative period. By taking advantage of indwelling catheters and continuous infusions, bupivacaine can be used to provide several days of effective analgesia.
Local anesthetics such as bupivacaine block the generation and the conduction of nerve impulses, presumably by increasing the threshold for electrical excitation in the nerve, by slowing the propagation of the nerve impulse, and by reducing the rate of rise of the action potential. In general, the progression of anesthesia is related to the diameter, myelination and conduction velocity of affected nerve fibers. Clinically, the order of loss of nerve function is as follows: (1) pain, (2) temperature, (3) touch, (4) proprioception, and (5) skeletal muscle tone. Systemic absorption of local anesthetics produces effects on the cardiovascular and central nervous systems. At blood concentrations achieved with therapeutic doses, changes in cardiac conduction, excitability, refractoriness, contractility, and peripheral vascular resistance are minimal. However, toxic blood concentrations depres
Euro-Celtique, S.A. Luxembourg
Gakh Yelena
Warden Jill
LandOfFree
Determination of corticosteroids in human plasma using... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Determination of corticosteroids in human plasma using..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Determination of corticosteroids in human plasma using... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3086097