Fexofenadine

Molecular formula C32H3gN04 Molecular weight 501.65 CAS Registry No 83799-24-0 Merck Index 13,4101 

Guard column 40 mm long 4 xm Purospher RP-18 LiChro Cart 4-4 

Mobile phase Gradient. MeCN buffer from 20 80 to 100 0 over 10 min, maintain at 0 100 for 3 min, re-equUibrate at initial conditions for 5 min. (The buffer was 10 mM ammonium acetate containing 0.1% formic acid (pH 3.2).) 

Detector MS, PE Sciex API 365 triple-stage quadrupole LC-MS-MS, PE Sciex Turbo Ion Spray interface, positive ion mode, needle voltage 5.2 kV, nebulizer gas air at 60 psi, curtain gas nitrogen at 40 psi, coUision cell gas nitrogen at 40 psi, turbo ionspray heater 375°, heater gas flow 7 L/min 

Gergov, M. Ojanpera, I. Vuori, E. Simultaneous screening for 238 drugs in blood by liquid chromatography-ion spray tandem mass spectrometry with multiple-reaction monitoring, J.Chromatogr.B, 2003, 795,41-53. 

---

The latter approach is used in the enantioselective determination of a Phase I metabolite of the antihistaminic drug, terfenadine. Terfenadine is metabolized to several Phase I compounds (Fig. 7-13), among which the carboxylic acid MDL 16.455 is an active metabolite for which plasma concentrations must often be determined. Although terfenadine can be separated directly on Chiralpak AD - an amy-lose-based CSP - the adsorption of the metabolite MDL 16.455 is too high to permit adequate resolution. By derivatizing the plasma sample with diazomethane, the carboxylic acid is converted selectively to the methyl ester, which can be separated in the presence of all other plasma compounds on the above-mentioned CSP Chiralpak AD [24] (Fig. 7-14). Recently, MDL 16.455 has been introduced as a new antihistaminic drug, fexofenadine. 

Antihistamines are drags used to counteract the effects of histamine on body organs and structures. Examples of antihistamines include diphenhydramine (Benadryl), loratadine (Claritin), fexofenadine (Allegra), and cetirizine (Zyrtec). A new antihistamine, deslorata-dine (Clarinex), is die active metabolite of loratadine and is intended to eventually replace loratadine (Claritin). Topical corticosteroid nasal sprays such as fluticasone propionate (Flonase) or triamcinolone ace-tonide (Nasacort AQ) are also used for nasal allergy symptoms. See Chapter 56 for more information on die topical corticosteroids. 

Decongestant and Expectorant Combinations Allegra-D Tablets—pseudoephedrine HC1, fexofenadine HC1... 

C Hs 71-43-2) see Budipine Clotrimazole Fexofenadine hydrochloride Ibuprofen Phenylmercuric borate ... 

C H2 C103 76811-97-7) see Fexofenadine hydrochloride 4-(2-chloro-2-oxoethyl)-l-piperidinecarboxylic acid phe-nylmethyl ester... 

C4H5CIO 4023-34-1) see Buprenorphine Fexofenadine hydrochloride Naltrexone Prazepam cyclopropanecarboxylic acid ethyl ester (C(,H o02 4606-07-9) see Pimozide... 

G16H20O3 169280-10-8) see Fexofenadine hydrochloride ethyl l-cyclopropyl-6,7-difluoro-S-methyl-l, 4-dihydro-4-oxoquinoline-3-carboxylate... 

C32H37NO4 76811-98-8) see Fexofenadine hydrochloride 4-[4-[4-(hydroxydiphenylmethyl)-l-piperidinyl]-l-oxo-butyl]-a,a-dimcthylbenzeneacetic acid ethyl ester (C34H4[N04 76812-02-7) see Fexofenadine hydrochloride 3a-hydroxy-2p,16p-dipiperidino-5a-androstan-17-one (C2cjH4jN202 13522-14-0) see Pancuronium bromide Vecuronium bromide 9-hydroxyellipticine... 

C2CI2O2 79-37-8) see Cefuroxime Diclofenae Dorzolamide Fexofenadine hydroehloride Granisetron Gusperimus trihydrochloride Indoramin Maprotiline Micinicate Ritonavir Saquinavir Sumatriptan Tacrolimus Tirofiban hydrochloride Tropisetron Viminol... 

Grant JA, Riethuisen JM, Moulaert B, DeVos C A double-blind, randomized, single-dose, crossover comparison of levocetirizine with ebastine, fexofenadine, loratadine, mizolastine, and placebo sup- 59 pression of histamine-induced wheal-and-flare response during 24 hours in healthy male subjects. 

First-generation antihistamines are effective, but associated sedation and psychomotor impairment limit chronic use. Efficacy and safety of second-generation antihistamines in children have been demonstrated in clinical trials.33 Cetirizine is indicated for children 6 months of age and older, loratadine for children 2 years of age and older, and fexofenadine for children 6 years of age and older.15... 

Simpson, K., Jarvis, B., Fexofenadine a review of its use in the management of seasonal allergic rhinitis and chronic idiopathic urticaria, Drugs... 

M. F., Wilkinson, G. R., Kim, R. B., OATP and P-glycoprotein transporters mediate the cellular uptake and excretion of fexofenadine, Drug Metab. Dispos. 1999, 27, 866-871. 

---