Pharmacokinetics of a New Quinolone, AM-833, in Mice, Rats, Rabbits, Dogs, and Monkeys

Transcription

1 ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Aug. 19, p //0030-0$0.00/0 Copyright 19, Americn Society for Microbiology Vol. 30, No. Phrmcokinetics of New Quinolone, AM-33, in Mice, Rts, Rbbits, Dogs, nd Monkeys HISAO KUSAJIMA, NORIHISA ISHIKAWA, MASAAKI MACHIDA, HIROSHI UCHIDA,* AND TSUTOMU IRIKURA Centrl Reserch Lbortories, Kyorin Phrmceuticl Co., Ltd., Tochigi, Jpn Received 1 December 195/Accepted My 19 The phrmcokinetics of AM-33 [,-diuuoro-1-(hfluoroethyl)-1,-dihydro-7-(-methyl-1-piperzinyl).- oxo-3-quinolinecrboxylic cid] were studied in mice, rts, rbbits, dogs, nd monkeys by reversed-phse high-performnce liquid chromtogrphy. AM-33 ws rpidly nd completely bsorbed from the digestive trcts of mice, rts, nd dogs. About hlf of AM-33 bound to rt nd dog serum proteins. Drug levels in lung, spleen, liver, nd kidney tissues of rts nd dogs were greter thn the respective levels in serum but lower in brin tissue. Drug levels in tissues declined with the decrese in levels in serum. AM-33 penetrted rpidly nd well into inflmmtory exudte of rts. Elimintion hlf-lives in serum were species dependent, rnging from 1.57 h in rbbits to 9. h in dogs. Profiles of drug levels in serum were dose relted over single dose rnge from to 0 mg/kg nd not modified significntly during multiple dosing in dogs. Unchnged AM-33 ws excreted in urine nd bile in both rts nd dogs. The metbolism of AM-33 ws suggested by evidence tht -h totl recovery of unchnged AM-33 in urine nd bile ccounted for bout hlf of the intrvenous dose in rts.,-difluoro-1-(-fluoroethyl)-1,-dihydro-7-(-methyl-1- piperzinyl)--oxo-3-quinolinecrboxylic cid (AM-33) is new pyridonecrboxylic cid derivtive (Fig. 1) with potent nd brod in vitro ntibcteril ctivity ginst grm-positive nd grm-negtive bcteri (1). The compound lso exhibited significnt ctivity ginst vrious experimentl infections (1). This pper describes the bsorption, distribution, nd excretion of AM-33 in vrious experimentl nimls. (This work ws presented in prt t the 3rd Interscience Conference on Antimicrobil Agents nd Chemotherpy, Ls Vegs, Nev., to October 193 [K. Tkgi, M. Hosk H. Kusjim Y. Oomori, K. Hiri, H. Uchid nd T. Irikur Progrm Abstr. 3rd Intersci. Conf. Antimicrob. Agents Chemother., bstr. no. 59, 193].) MATERIALS AND METHODS Chemicls. AM-33 (lot no ) nd n internl stndrd (1-ethyl--fluoro-1,-dihydro-7-imidzol-1-yl--oxo-3- quinolinecrboxylic cid) for nlysis were synthesized in our lbortories. All other regents were of nlyticl grde. Animls. Mle ICR mice (body weight, bout 30 g), mle Wistr rts (50 to 50 g), mle Jpnese White rbbits (3.1 to 3.5 kg), mle nd femle begle dogs (.5 to 13.0 kg), mle mongrel dogs (.5 nd 11.0 kg), nd mle cynomolgus monkeys (5.0 to 5.7 kg) were treted. Unless otherwise stted, mle begle dogs were used. Drug dministrtion. AM-33 ws dministered to fsting nimls except when repetedly given to dogs. A suspension for orl dministrtion ws prepred by homogenizing the powder in 0.3 to 0.5% crboxymethyl cellulose sodium queous solution. An queous solution for intrvenous nd orl dministrtion ws prepred by dissolving AM-33 in 0.1 N sodium hydroxide nd then djusting the ph to 9 to with N hydrochloric cid in which osmolrity ws mintined t physiologicl pressure by ddition of sodium chloride. Single orl doses were given to 30 mice ( or 50 mg/kg) * Corresponding uthor. nd rts ( mg/kg) s suspensions nd to dogs (,, or 0 mg/kg) s hrd geltin cpsules. Additionl single orl doses were given to four rts ( mg/kg) nd six dogs ( or mg/kg) s n queous solution. Repeted orl doses were given to three dogs twice dily (0,,, 3,, 5, 7, 0, nd 9 h fter the first dose) for 5 dys t dose of mg/kg s cpsules. Bolus intrvenous doses were given to 0 mice ( or 50 mg/kg by til vein), rbbits ( mg/kg by er vein), dogs ( or mg/kg by foreleg vein), nd 3 monkeys ( mg/kg by leg vein) by direct injection nd to rts ( mg/kg) through polyethylene ctheter inserted into the femorl vein. For determintion of levels in tissues, AM-33 ws given to five rts s bolus injection (3.90 mg/kg) nd then infused t rte of 1.05 mg/kg per h for h, nd AM-33 ws given to three femle begle dogs s bolus injection (. mg/kg) nd then infused t rte of 0.50 mg/kg per h for 3.5 h through polyethylene ctheter introduced into the femorl nd foreleg veins, respectively. In n experiment on urinry nd biliry excretion in dogs, the queous solution ( mg/kg) ws intrvenously given to two mle mongrel dogs vi polyethylene ctheter inserted into the foreleg vein. Ringer solution contining 0.% (wt/vol) glucose ws intrvenously given dropwise t rte of 0 ml/h during collection of urine nd bile smples. In four rts AM-33 ( mg/kg) ws intrvenously injected through polyethylene ctheter inserted into the femorl vein for collection of urine nd bile. The grnulom pouches of rts were prepred by the Selye procedure (7). Acute exudtive inflmmtion ws induced by injecting 1 ml of olive oil contining croton oil (1%) into n ir pouch which hd been produced by introducing 0 ml of ir into subcutneous tissue on the dors of rts; the ir ws removed 3 dys lter. AM-33 ( mg/kg) ws intrvenously injected into four rts on dy of inflmmtion. Preprtion of ssy specimens. Mouse blood smples were tken by decpittion t 0.5, 1,, 3,.5, nd h fter orl dosing nd 0.17 nd 0.33 h fter intrvenous dosing. Rt blood smples were serilly collected t the sme times s mouse blood smples through polyethylene ctheters in- 30 Downloded from on Jnury 5, 019 by guest

2 VOL. 30, 19 F F rurw FIG. 1. Chemicl structure of AM-33. serted into the femorl rteries. Blood smples from other species were obtined by venipuncture t predetermined times fter dosing: rbbits, 0.17, 0.33, 0.5, 1,, 3, 5, 7, nd 9 h; dogs, 0.5, 1,, 3,, 9, 1,, 3, nd h for orl dosing nd 0.0, 0.17, nd 0.33 h for intrvenous dosing (single dosing) or,,,,,,, 50, 7, 7, 9, 9, 0,,,, nd 1 h fter first dosing (repeted dosing); monkeys, 0.5, 0.5, 1,, 3,, 9, 1, nd h. Serum ws seprted by centrifugtion. For tissue distribution experiments, rts nd dogs were scrificed t the end of infusion by puncture of the bdominl nd femorl rteries, respectively, nd then blood nd brin (rt only), lung, kidney, liver, nd spleen tissues were hrvested. The tissues were weighed nd then homogenized with four times the volume of 1/15 M phosphte buffer (ph 7.0) by using Polytron homogenizer (Kinemtic GmbH). The homogente ws centrifuged t,000 x g for 0 min to seprte the superntnt. Urine nd bile smples of rts were collected through polyethylene ctheters inserted into the bldders nd common bile ducts, respectively, for 0 to 3, 3 to, nd to h. Blood, urine, nd bile smples of mongrel dogs were tken through polyethylene ctheters inserted into the femorl veins, left nd right ureters, nd common bile ducts, respectively. Blood ws tken t 1, 3, 5, 7, 9, 11, 1, nd 0 h; urine nd bile were collected t 0 to, to, to, to, to, to 1, 1 to 1, nd 1 to 0 h. Grnulom exudte nd blood of rts were tken through needles for injection from dorsl pouches t 0.5, 0.5, 1,,,,, nd h. All specimens were stored t -0 C until nlyzed. Protein binding. In vivo protein binding of AM-33 ws exmined by the ultrfiltrtion method. From rts given AM-33 orlly blood smples were tken t 0.5, 1,,, nd h fter dosing, nd from five dogs given 0 mg ech orlly blood ws tken t 0.5, 0.5, 0.75, 1,, nd h fter dosing. Serum ws seprted by centrifugtion t room temperture. Portions (5 ml) of serum were loded on n Amicon Centriflo CF-5 membrne. The concentrtions in serum nd ultrfiltrte were regrded s the totl nd unbound concentrtions, respectively. The extent of dsorption of AM-33 to the membrne ws determined by using 1/15 M phosphte buffer (ph 7.) contining AM-33 in rnge from 0.1 to,ug/ml. The binding rte ws corrected with the extent of dsorption (%). Assy procedure. The high-performnce liquid chromtogrphy system consisted of constnt-flow pump (Hitchi model 55 liquid chromtogrph), n utomted smple injector (Kyow Seimitsu model KSST-01 utosmpler), vrible-wvelength UV detector (Hitchi model 3-1 UV monitor), nd dt processor (Hitchi model 33 Chromto-processor). A smple of biologicl specimen (0.1 to 1 ml) ws mixed with 0.1 ml of n internl stndrd solution, 1 ml of 0.5 M phosphte buffer (ph 7.5), nd ml of chloroform. The internl stndrd solution ws prepred by dissolving 1- ethyl--fluoro-1,-dihydro-7-imidzol-1-yl--oxo-3-quinolinecrboxylic cid in 0.0 N sodium hydroxide (30 to 150,ug/ml). The resulting mixture ws vigorously shken for S PHARMACOKINETICS OF AM min nd centrifuged t,000 x g for 5 min, nd 5 ml of the chloroform lyer ws removed nd evported. The resulting residue ws dissolved in 0.1 ml of mixture (1:1 [vol/vol]) of cetonitrile nd 0.0 M phosphoric cid. A smple (5,ul) of the solution ws injected into.0 mm (inside dimeter) by 5 cm stinless steel column pcked with Nucleosil 5 CN (Mcherey-Ngel) nd equipped with Nucleosil 5 CN gurd column (.0 mm [inside dimeter] by mm). The eluting mobile phse ws 9:1 (vol/vol) mixture of cetonitrile nd 0.0 M phosphoric cid. The flow rte ws 1.1 ml/min. The wvelength of the UV monitor ws set t 7 nm. Clibrtion stndrds were prepred by dding 0.1 ml of 0.0 N sodium hydroxide contining AM-33 to 1 ml of blnk biologicl specimen nd ssying s described bove. The concentrtion of AM-33 ws clculted from the clibrtion curve constructed by plotting the pek height rtios of AM-33 to the internl stndrd versus the spiked concentrtions of AM-33. The sensitivity of this procedure ws 0.01,ug/ml in serum, urine, nd bile nd 0.05,ug/g in tissues when 1 ml ech of serum, urine, bile, or tissue homogente ws used. Urine nd bile were diluted to 0 times with 0.5 M phosphte buffer (ph 7.5). The overll recovery rtes of AM-33 from serum nd tissues were 5% (t 5.0,ug/ml) nd 9 to 97% (t 5,ug/g), respectively. The coefficients of vrition were 0. nd 1.% t 0.5 nd 5.0,ug/ml of serum, respectively, nd 0. to. nd 0. to 1.1% t.5 nd 5.1,ug/g of tissue, respectively. Peks of AM-33 nd the internl stndrd were not disturbed by control blnk extrct. Stndrd solution of AM-33 ws stble for t lest 1 week t C. Typicl chromtogrms re presented in Fig.. This procedure provided concentrtions of unchnged drug, which were confirmed s follows. A portion of chloroform extrct of serum, urine, nd bile smples of rts nd dogs, which were prepred by the nlyticl method described bove, ws developed on silic gel 0 F5 thin-lyer chromtogrphy plte (E. Merck) with mixture of chloroform, methnol, benzene, diethylmine, nd wter (0:0::7: [vol/vol]), resulting in one spot of AM-33 lone. Phrmcokinetic nlysis. Results re expressed s the men nd the stndrd error. The significnce of the dt (A) (B) (C) 1 I I I I I,I I Time (min) FIG.. Typicl chromtogrms of dog serum. (A) Control dog serum; (B) dog serum spiked with internl stndrd (pek 1) nd 5.05,ug of AM-33 per ml (pek ); (C) dog serum 1 h fter orl dministrtion of AM-33 t dose of mg/kg. Downloded from on Jnury 5, 019 by guest

3 30 KUSAJIMA ET AL. ws evluted by the Student t test. In species other thn mice, phrmcokinetic prmeters were clculted from individul concentrtions in serum, but in mice individul concentrtions in serum were verged nd the men vlue thus obtined ws used to clculte phrmcokinetic prmeters. The serum concentrtion/time curves fter intrvenous dministrtion in nimls other thn monkeys were nlyzed by the two-comprtment open model, wheres those in monkeys followed one-comprtment kinetics. The concentrtion in serum fter orl dministrtion ws nlyzed by one-comprtment kinetics. Phrmcokinetic prmeters were obtined s follows. TmX ws the pek time observed. Cmx ws the pek concentrtion observed. tj1 ws the hlf-life clculted from the elimintion rte constnt determined by liner regression nlysis. AUCo ws the re under the curve (AUC) clculted s the sum of AUC obtined from zero to the lst time by the trpezoidl rule nd the rtio of the lst concentrtion mesured to the elimintion rte constnt in the terminl phse. Concentrtions in serum during repeted dosing were simulted by using multiple-dose kinetic eqution with first-order bsorption nd elimintion rte constnt bsed on the onecomprtment model. RESULTS Levels in serum. Profiles of AM-33 levels in the ser of mice, rts, rbbits, dogs, nd monkeys given single intrvenous dose ( mg/kg) re illustrted in Fig. 3. These nimls exhibited reltively wide species difference in elimintion rtes (Tble 1). Mice, rts, rbbits, dogs, nd monkeys showed respective hlf-lives of 1.95,.5 ± 0.07, 1.57 ± 0.11, 9. ± 0.0, nd 3.5 ± 0.15 h during the elimintion phse. On the other hnd, these nimls showed reltively similr volumes of distribution (V~s): mice, 1.7; rts, 1.30 ± 0.0; rbbits, 1.07 ± 0.03; dogs, 1. ± 0.0; nd monkeys, 1.1 ± 0.0 liters/kg. These vlues suggest good C 1 c, 0 o 1.t Rbbi t Dog 3 1 Time ( hr ) FIG. 3. Men levels of AM-33 in serum fter intrvenous injection t dose of mg/kg in five mice (A), four rts (A), four rbbits (E), six dogs (0), nd three monkeys (0). ANTIMICROB. AGENTS CHEMOTHER. TABLE 1. Phrmcokinetic prmeters of AM-33 fter intrvenous injection of mg/kg into mice, rts, rbbits, dogs, nd monkeys Animl (no.) Prmeter V,, (liters/kg) tl13(h) AUCo,(Lg * h/mnl) Mouse (5) Rt () 1.30 t t t 1.1 Rbbit () 1.07 t t t 0.9 Dog () 1. t t t.1 Monkey (3) 1.1 t t t 1. Volume of distribution t stedy stte; thmp, biologicl hlf-life during the elimintion phse; AUCO, re under the serum concentrtion/ time curve from zero to infinity. Numbers represent mens + the stndrd errors. V,,, distribution of AM-33 in the body. In mice, rts, nd dogs, levels of AM-33 in serum fter n intrvenous dose were compred with those fter n orl dose (Fig. ). In mice receiving dose of mg/kg, the men AUC vlues fter intrvenous nd orl (suspension) dministrtion were 1.7 nd.1,ug. h/ml, respectively. The corresponding vlues t dose of 50 mg/kg were 73. nd 71. pjlg. h/ml. In rts receiving dose of mg/kg, the men AUC vlues were.7, 5., nd 5.,ug. h/ml fter intrvenous, orl queous solution, nd orl suspension dministrtions, respectively. In dogs receiving dose of mg/kg, the men AUC vlues were 3, 3, nd 1,ug- h/ml fter intrvenous, orl queous solution, nd orl powder dministrtions, respectively. The corresponding vlues t dose of mg/kg were.,., nd.9,jg * h/ml. These results suggest tht orl bsorption of AM-33 ws lmost complete in these nimls, even if AM-33 ws dministered s crystlline powder. Seril orl dministrtions of AM-33 to dogs produced grdul increses in levels in serum (Fig. 5) when mg/kg ws given twice dy. The level in serum of ,ug/ml t h fter the third dose ws 1.5 times higher thn the concentrtion fter the corresponding first dose (1.7 ± 0.13,ug/ml) nd bout equl to tht fter the ninth dose (.35 ± 0.1 1xg/ml). The respective miniml concentrtions on dys, 3,, nd 5 were mesured s 1.0 ± 0., 1.30 ± 0.1, 0.9 ± 0.09, nd 0.91 ± 0.09,ug/ml. These vlues were firly constnt over the experimentl period. The solid line in Fig. 5 ws obtined by computer simultion using the one-comprtment kinetic eqution, where prmeters were tenttively chosen s follows: n bsorption rte constnt of 5.00 h-1, n elimintion rte constnt of 0.00 h-1, nd rtio of the volume of distribution to the bsorbed frction of the dose of 1.0 liters/kg. The good fit suggested tht orl bsorption of AM-33 ws much fster thn its elimintion from serum. No specil ccumultion of AM-33 in dogs ws postulted bsed on the good simultion of experimentl dt with the multiple-dose kinetic eqution. This ws lso supported by the evidence tht the elimintion hlf-life (5.3 ± 0.33 h) fter the ninth dministrtion ws not significntly chnged from tht (5.90 ± 0.0 h) fter the first dministrtion (P > 0.05). The Cmx nd AUC of dogs orlly given,, nd 0 mg/kg exhibited dose-relted reltionship, wheres t1/ vlues were dose independent (Tble ). These results indicte tht liner phrmcokinetic behvior occurs over dose rnge from to 0 mg/kg in dogs. Distribution. From 1 to 57% of AM-33 ws bound in rt serum nd 1 to 1% ws bound in dog serum t totl concentrtions rnging from 1 to 7,ug/ml. The binding rte ws bout hlf of the totl AM-33 nd virtully independent of AM-33 concentrtion in the rnge studied. Downloded from on Jnury 5, 019 by guest

4 VOL. 30, 19 co I 0 - LO 1 Mouse Dog Time ( hr) FIG.. Men levels of AM-33 in serum fter intrvenous (O) or orl (0) dministrtion t dose of mg/kg in five mice, four rts, nd six dogs. The men levels of AM-33 in serum nd pouch fluid when AM-33 ws intrvenously injected t dose of mg/kg into rts with grnulom pouches re present in Fig.. The levels in serum decresed to 3.31 ± 0. nd 0.3 ± 0.03,ug/ml t nd h postdministrtion, respectively. The levels in pouch fluid reched peks of.1 ± 0.09,ug/ml t h postdministrtion nd then decresed more grdully with hlf-life of.3 h, resulting in levels in pouch fluid four times higher thn levels in serum t h postdministrtion. The men penetrtion rtio to pouch fluid (AUCpouch fluid/ AUCserum) ws 1.1. AM-33 levels in brin, lung, liver, spleen, nd kidney tissues of rts were mesured both t the end of infusion nd t h postinfusion. The levels in lung, liver, spleen, nd kidney tissues of dogs were determined t the end of constnt infusion. Rts showed tissue/serum distribution rtios of. ± 0., 3.1 ± 0.1,.3 ± 0.1, 1.1 ± 0.1, nd 0.17 ± 0.0 in kidney, liver, spleen, lung, nd brin tissues, respectively, t the end of infusion. The respective rtios t h postinfusion were.1 ± 0., 3.3 ± 0.1,.9 ± 0.1, 1. ± 0.1, nd 0.5 ± 0.0. The distribution rtios in dogs were 3.5 ± 0.0,. + 0.,.1 ± 0.1, nd 1. ± 0. in liver, spleen, kidney, nd lung tissues, respectively. These results indicte tht AM-33 is well distributed mong vrious tissues, but not in brin, nd is eliminted from the tissues t rtes similr to tht of elimintion from serum, becuse there were no significnt chnges in distribution rtio with time. Excretion. Excretion of AM-33 urine nd bile ws exmined in rts given single intrvenous or orl dose of mg/kg (Tble 3). The pek levels of AM-33 were nd 3 ± 95,ug/ml in 0- to 3-h pooled urine fter intrvenous cn m 0 C, 0 E'Ln ' Drug PHARMACOKINETICS OF AM dministrtion I I I I I I I I I Time ( hr) FIG. 5. Men (t the stndrd error) levels of AM-33 in serum during repeted orl dministrtion of AM-33 t dose of mg/kg twice dily for 5 dys in three dogs. A simultion curve ws clculted bsed on one-comprtment kinetics: bsorption rte constnt, 5.00 h-i; elimintion rte constnt, 0.00 h-i; rtio of the volume of distribution to the frction of the dose bsorbed, 1.0 liters/kg. nd orl dministrtions, respectively. The corresponding levels in bile were.1 +. nd ,ug/ml. The levels in - to -h pooled urine smples were ± 0 nd ,ug/ml fter intrvenous nd orl dministrtion, respectively. The corresponding levels in bile were.1 ±. nd 11.0 ±.1,ug/ml. The recovery of AM-33 in urine t h postdministrtion ws.9 +. nd 3. ± 5.% of the dose fter intrvenous nd orl dministrtions, respectively. The respective percentges found in bile were. ± 1.9 nd 5.7 ± 1.%. Thus, 9.7 nd 1.9% of the dose ws totlly excreted into both urine nd bile in h s unchnged AM-33. The levels of AM-33 in serum, urine, nd bile were determined in two mongrel dogs given single intrvenous dose of mg/kg (Fig. 7). In this experiment, the dogs were ctheterized for collection of urine nd bile. The elimintion hlf-lives were.0 nd.0 h, which were shorter thn those of intct dogs (Tble 1). The levels of AM-33 in urine of dogs were nd 5,ug/ml t 0 to h postdministrtion nd bout 0 jig/ml t 1 h postdministrtion. The levels of AM-33 in bile of dogs were 370 nd 31 jig/ml t 0 to h postdministrtion nd bout 0,ug/ml t 1 h postdministrtion. Excretion percentges in urine nd bile of dogs were 1.0 to.7 nd 5.3 to 5.7% of the dose, respectively, t 1 h. These results indicted tht biliry excretion contributed more to totl excretion in dogs thn in rts. TABLE. Dose Phrmcokinetic prmeters of AM-33 fter orl dministrtion in dogs Prmeter (mg/kg) Cmx (qg/ml) Tmx (h) tii (h) AUCO_ (1Lg * h/ml) 1.7 ± ± ± ± ± ± 0.7. ± ±. 0.5 ± 1.. ± 0..3 ± ± 3.3 Cm Pek concentrtion observed; Tmx, pek time observed; t11, biologicl hlf-life; AUCO,, re under the serum concentrtion/time curve from zero to infinity. Numbers represent mens ± the stndrd errors for six dogs. Downloded from on Jnury 5, 019 by guest

5 30 KUSAJIMA ET AL. DISCUSSION This study demonstrted tht AM-33 ws rpidly nd completely bsorbed from the gstrointestinl trct, modertely bound to serum proteins, well distributed mong vrious tissues except brin, nd excreted in urine nd bile without ccumultion in experimentl nimls. When AM-33 ws given orlly, its pek level in dog serum ws similr to tht of ofloxcin (, ) but higher thn those of other pyridonecrboxylic cid derivtives (-5, 9). In experimentl nimls, precise biovilbility dt of other derivtives re not vilble, but AM-33 exhibited lmost perfect systemic vilbility in mice, rts, nd dogs. Good vilbility of crystlline AM-33 dministered orlly ws lso confirmed in dogs. The present study reveled lrge interspecies difference in the elimintion hlf-life of AM-33 in mice, rts, rbbits, monkeys, nd dogs. Rbbits hd the shortest hlf-life (1.57 h), nd dogs exhibited the longest hlf-life (9. h). Animls lrger in body weight tended to show longer hlf-life of AM-33, but rbbits showed exceptionlly rpid elimintion of AM-33, suggesting extensive metbolism in rbbits (H. Kusjim T. Ooie, F. Kwhr nd H. Uchid J. Chromtogr., in press). AM-33 exhibited elimintion rtes similr to those of pefloxcin () nd enoxcin (, 5, 9) in mice nd rts but much slower elimintion in dogs compred with known nlogs. These observtions suggest the possibility of n extended dosge intervl of AM-33 in clinicl use. The volumes of distribution of AM-33 were greter thn 1 liter/kg in ll of the species investigted, suggesting tht AM-33 cn penetrte into both extrcellulr nd intrcellulr spces. This ws confirmed by the findings of good penetrtion into the grnulom pouch nd vrious tissues. The high distribution of AM-33 provides promising possibility tht AM-33 my be useful not only for urinry nd biliry trct infections but lso for vrious systemic infections. The levels in tissues of rts declined t rtes similr to tht in serum, lthough elimintion from brin tissue ws E 0r 0.O- t, x c (3 ' E do Time ( hr) FIG.. Men levels of AM-33 in serum nd exudte fter intrvenous injection t dose of mg/kg in four rts with grnulom pouches. Symbols: 0, exudte; 0, serum. ANTIMICROB. AGENTS CHEMOTHER. TABLE 3. Excretion of AM-33 in urine nd bile fter intrvenous or orl dministrtion of mg/kg in rts Excretion of AM-33 in: Time (h) Urine Bile Level Recovery Level Recovery (jig/ml) (% of dose) (pig/ml) (% of dose) Intrvenous dministrtion ± ±.0.1 ±. 1.5 ± ± 1.3 ± ±. 1. ± 0. - ± ±..1 ±. 3. ± ±.7. ± 1.9 Orl dministrtion ± ± ±.1. ± ± 7. ± ±.9 1. ± ± 1 1. ± ±.1.3 ± ± ± 1. Numbers represent mens - the stndrd errors for four rts. slightly slower. Levels in serum during repeted dosing of dogs were well described by the multiple-dose phrmcokinetic eqution, nd the elimintion hlf-life fter the lst dose ws not significntly chnged from tht fter the first dose. This evidence suggests no ccumultion of AM-33 in rts nd dogs. The -h recovery percentges of unchnged AM-33 in urine nd bile were.9 nd.% of the dose, respectively, is,-. - > E _- E - > E L _% L- - > E. _ cm v O'D o-o I., L- Gi 5 L Time ( hr ) FIG. 7. Levels of AM-33 in serum, urine, nd bile nd its cumultive recovery in urine nd bile fter intrvenous injection of mg/kg into two mongrel dogs. Open nd closed circles represent AM-33 levels in the serum, urine, nd bile of dogs A nd B, respectively. Solid nd broken lines represent recovery of AM-33 from urine nd bile of dogs A nd B, respectively.. > Downloded from on Jnury 5, 019 by guest

6 VOL. 30, 19 PHARMACOKINETICS OF AM fter intrvenous dministrtion to rts. The corresponding dog dt lso cnnot ccount for the complete excretion of AM-33. The evidence suggests some metbolism of AM-33 in rts nd dogs (Kusjim et l., in press). LITERATURE CITED 1. Hiri, K., H. Aoym M. Hosk Y. Oomori, Y. Niwt S. Suzue, nd T. Irikur. 19. In vitro nd in vivo ntibcteril ctivity of AM-33, new quinolone derivtive. Antimicrob. Agents Chemother. 9:59-.. Monty, G., Y. Goueffon, nd F. Roquet. 19. Absorption, distribution, metbolic fte, nd elimintion of pefloxcin mesylte in mice, rts, dogs, monkeys, nd humns. Antimicrob. Agents Chemother. 5: Ngtsu, Y., K. Endo, nd T. Irikur Studies on the fte of 'C-lbeled AM-715. Chemotherpy (Tokyo) 9(Suppl. ): 5-.. Nkmur S., N. Kurobe, S. Kshimoto, T. Ohue, Y. Tkse, nd M. Shimizu Phrmcokinetics of AT- dministered orlly to mice, rts, dogs, nd monkeys. Antimicrob. Agents Chemother. : Nkmur S., N. Kurobe, S. Kshimoto, T. Ohue, Y. Tkse, nd M. Shinmizu. 19. Absorption, distribution, excretion nd metbolism of AT- in experimentl nimls. Chemotherpy (Tokyo) 3(Suppl. 3):-9.. Okzki, O., T. Kurt K. Hshimoto, K. Sudo, M. Tsumur nd H. Tchizw. 19. Metbolic disposition of DL-0. The second report: bsorption, distribution nd excretion of 'C-DL- 0 in vrious niml species. Chemotherpy (Tokyo) 3(Suppl. 1): Selye, H Use of "grnulom pouch" technic in the study of ntiphlogistic corticoids. Proc. Soc. Exp. Biol. Med. : Tsumur M., K. Sto, T. Une, nd H. Tchizw. 19. Metbolic disposition of DL-0. The first report: comprison between bsorption nd excretion of DL-0 in the dog nd monkey by biossy nd HPLC methods. Chemotherpy (Tokyo) 3(Suppl. 1): Ymguchi, T., R. Suzuki, nd Y. Sekine. 19. Phrmcokinetics of new ntibcteril gent AT-. II. Plsm levels nd urinry excretion of AT- nd its metbolites in mice, rts, cts, dogs nd monkeys. Chemotherpy (Tokyo) 3(Suppl. 3):3-. Downloded from on Jnury 5, 019 by guest