The comparative arthropathy of fluoroquinolones in dogs

1. Fluoroquinolone antibiotics are generally only prescribed to paediatric patients on compassionate grounds. This is because they are known to cause lesions in the cartilage of the major diarthroidal joints in immature experimental animals. As dogs are considered to be the most sensitive species, a series of studies was performed to compare the potential for grepafloxacin (a new fluoroquinolone) to cause arthropathy to that of ofloxacin and ciprofloxacin in juvenile (3 month old) beagles. 2. Grepafloxacin was administered once daily to male juvenile dogs at dosages of up to 100 mg/kg/day (intravenously), 60 mg/kg/day (orally) or 30 mg/kg/day (subcutaneously) for 1 week. Blister formation was observed on the surface of the joints in one of the three animals treated with grepafloxacin intravenously at 100 mg/kg/day. No abnormalities were observed at lower dosages or when grepafloxacin was administered orally or subcutaneously, regardless of dose. In animals treated with ofloxacin or ciprofloxacin at dosages of 10-30 mg/kg/day, blister formation or erosion was observed on the surface of joints regardless of dose or route of administration. 3. Histopathological examination of the joint surfaces of affected animals revealed the loss of cartilaginous matrix and chondrocytes, cavitation within the intermediate zone of cartilage accompanied by cartilage fibrillation or chondrocyte clustering, or loss of the surface layer which covers the cavitation (or loss of outer wall of the cavity). These findings were not present in the absence of grossly observed lesions. 4. Absorption following oral administration of grepafloxacin was low. Examination of plasma concentrations of drug following intravenous administration showed that joint toxicity was seen with ofloxacin and ciprofloxacin at maximum concentrations as low as 3.80 and 4.24 mg/l, respectively, while plasma levels of grepafloxacin of up to 11.95 mg/l failed to cause such lesions. When the concentration of grepafloxacin was 18.69 mg/l a single joint lesion was seen. Following subcutaneous administration of grepafloxacin, systemic exposure (area under the curve) of approximately 1.5 times that seen in man was not associated with joint lesions. However, lesions were noted for ofloxacin and ciprofloxacin treated animals at exposures equal to or below those seen in man. Therefore grepafloxacin appeared to have a relatively low potential for joint toxicity; this was not due to lack of penetration into the synovial fluid.

N-Methyl-D-aspartate antagonists and apoptotic cell death triggered by head trauma in developing rat brain

Morbidity and mortality from head trauma is highest among children. No animal model mimicking traumatic brain injury in children has yet been established, and the mechanisms of neuronal degeneration after traumatic injury to the developing brain are not understood. In infant rats subjected to percussion head trauma, two types of brain damage could be characterized. The first type or primary damage evolved within 4 hr and occurred by an excitotoxic mechanism. The second type or secondary damage evolved within 6-24 hr and occurred by an apoptotic mechanism. Primary damage remained localized to the parietal cortex at the site of impact. Secondary damage affected distant sites such as the cingulate/retrosplenial cortex, subiculum, frontal cortex, thalamus and striatum. Secondary apoptotic damage was more severe than primary excitotoxic damage. Morphometric analysis demonstrated that the N-methyl-D-aspartate receptor antagonists 3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonate and dizocilpine protected against primary excitotoxic damage but increased severity of secondary apoptotic damage. 2-Sulfo-alpha-phenyl-N-tert-butyl-nitrone, a free radical scavenger, did not affect primary excitotoxic damage but mitigated apoptotic damage. These observations demonstrate that apoptosis and not excitotoxicity determine neuropathologic outcome after traumatic injury to the developing brain. Whereas free radical scavengers may prove useful in therapy of head trauma in children, N-methyl-D-aspartate antagonists should be avoided because of their propensity to increase severity of apoptotic damage.

A comparative study of the repeat dose toxicity of grepafloxacin and a number of other fluoroquinolones in rats

Grepafloxacin is a new oral fluoroquinolone with potent activity against community acquired respiratory pathogens, including Streptococcuspneumoniae, and pharmacokinetic properties which allow once daily dosing. As part of its safety evaluation a study of 4 weeks duration was performed to compare the toxicity of grepafloxacin with that of a number of commercially available quinolones in the rat. Groups of eight male Sprague-Dawley rats received either control material or grepafloxacin, enoxacin, lomefloxacin, ofloxacin or ciprofloxacin at an oral dosage of 300 mg/kg/day for 4 consecutive weeks. Effects related to the antibacterial activity of the drugs were seen as increased caecal weight, decreased urinary excretion of sodium, increased water consumption, decreased urine volume, increased urine osmolality, soft stools and suppressed body weight gain. It is well documented that fluoroquinolones can cause lesions in the cartilage of the major diarthrodial joints, and blister formation or erosion on the joint surface was observed in all quinolone-treated groups other than the grepafloxacin group. Some quinolones, have been found to cause crystalluria, which is often associated with secondary nephropathy in laboratory animals due to the poor solubility of quinolones under the alkaline conditions of the urine. In the present study, needle-like crystals in the urinary sediment were observed in enoxacin and ciprofloxacin treated groups only. In conclusion, grepafloxacin was well tolerated and showed a low potential for joint toxicity and crystalluria compared to other quinolones.

Possible involvement of a sigma receptor subtype in the neck dystonia in rats

To clarify which subtype of sigma receptors is involved in the sigma receptor-mediated neck dystonia in rats, we examined whether 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride (SA4503), a selective sigma1 receptor agonist, and 1,3-di-(2-tolyl)guanidine (DTG), a sigma1 and sigma2 receptor agonist, induce neck dystonia in rats. Microinjection of SA4503 into the red nucleus of rat brain scarcely produced neck dystonia at the concentration of 10 nmol/0.5 microl. On the contrary, DTG produced significant dystonia at a concentrations of more than 5 nmol/0.5 microl. These results indicate that the sigma2 receptor subtype, but not sigma1 receptor subtype, may play an important role in the sigma receptor-mediated neck dystonia in rats.

Reduction of 4-cyclohexyl-1-[(1R)-1,2-diphenylethyl]-piperazine-induced memory impairment of passive avoidance performance by sigma 1 receptor agonists in mice

Intraperitoneal administration of 4-cyclohexyl-1-[(1R)-1,2-diphenylethyl]-piperazine (CDEP) immediately after the training session produced significant memory impairment in the mouse passive avoidance performance. Interestingly, this memory impairment was alleviated by subcutaneous administrations of sigma receptor agonists, (+)-N-allylnormetazocine ((+)-SKF-10,047), (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3-PPP) and 1,3-di(2-tolyl)guanidine (DTG) immediately after the training session. In particular, the remarked recovery for this memory impairment was produced by (+)-SKF-10,047. A receptor binding study showed that CDEP possessed high affinities for both sigma 1 and sigma 2 receptor subtypes (IC50 1.4 +/- 0.3 nM for sigma 1 receptor subtype, 1.8 +/- 0.3 nM for sigma 2 receptor subtype), while (+)-SKF-10,047 had a high selectivity for the sigma 1 receptor subtype. These findings suggest that the sigma receptor, particularly sigma 1 receptor subtype, may play an important role in the CDEP-induced impairment of learning and memory processes.

Comparative grepafloxacin phototoxicity in mouse skin

This study was performed in order to compare the phototoxic potential of grepafloxacin (a new fluoroquinolone for the treatment of respiratory tract infections) with that of a number of marketed fluoroquinolones. Groups of Balb/c mice received either control material or grepafloxacin, lomefloxacin, sparfloxacin, ofloxacin, ciprofloxacin or enoxacin at an oral dose of 200 mg/kg before being exposed to 20 J/cm2 longwave ultraviolet irradiation for 110-115 min. Lomefloxacin and sparfloxacin caused erythema and oedema which were often severe and lasted the full 7 days of the study. Enoxacin caused a long-lasting erythema, while the erythema seen following the administration of grepafloxacin, ciprofloxacin and ofloxacin was relatively mild and short-lived. The results of this study demonstrate the good safety profile of grepafloxacin in terms of phototoxicity.

Blood and cerebral concentrations of the new potential analgesic UP 26-91 measured in vivo by microdialysis after toxic doses

The concept of proportionality between the pharmacological effects of drugs and their dosage has been questioned since the discovery of saturable phenomenon for some drug dispositions, either during their absorption or their elimination. Such saturation may also occur during the distribution phase in the tissues. This phenomenon, however, is often difficult to demonstrate and microdialysis is a powerful technique to assess precise changes in drug concentrations in tissue. This technique has been used to compare brain and blood concentrations of a potential analgesic, UP 26-91 (3-¿[2-[4-(2,4-difluorophenyl)piperazin-1-yl]ethyl]thio¿ -1,2,4-triazolo[4,3-a]pyrioline, citrate salt, CAS 115762-17-9 for the base), at different intravenous doses. Microdialysis probes were surgically implanted in the cerebral cortex and the jugular vein of male Sprague-Dawley rats (about 350 g). A single dose of radiolabelled 14(C) UP 26-91 mixed with unlabelled drug was injected into the animal's tail vein. Three doses of drug (2.5, 12.5 and 22.5 mg.kg-1) were tested, with three rats for each dose. All the doses consisted of the same amount of radiolabelled product, used as a tracer, supplemented by the amount of non-radiolabelled UP 26-91 necessary to reach the desired concentration. The rats were conscious, freely moving and had free access to food and water. Microdialysis samples were collected at the rate of 1 microliter.min-1, and sampled every 15 min for 16-17 h. The two highest doses were in the range of those used for toxicological studies. Blood UP 26-91 radioactivity concentrations were superimposable independent of the dose. Thus, it can be concluded that there was a linear relationship between blood concentrations and administered doses. By contrast, the brain concentration for the highest administered dose was statistically higher than the two others (p < 0.05), which demonstrated that UP 26-91 exhibited a non-linear pharmacokinetics in the brain. It is therefore likely that a saturable transport mechanism occurs across the blood-brain barrier. This study demonstrates that blood toxicokinetics may not correctly reflect tissue exposure to a drug.

BMS-181885, a 5-HT1B/1D receptor ligand, in experimental models predictive of antimigraine activity and coronary side-effect potential

Many acutely acting antimigraine drugs have the ability to constrict porcine arteriovenous anastomoses as well as the human isolated coronary artery. These two experimental models seem to serve as indicators, respectively, for the therapeutic and coronary side-effect potential of the compounds. Using these two models, we have investigated the effects of BMS-181885 (3-[3-[4-(5-methoxy-4-pyrimidyl)-1-piperazinyl]propyl]-5-(1,2-dioxo-4-me thyl-3-cyclobuten-3-yl)amino-1H-indole), a 5-HT1B/1D receptor ligand. In anaesthetised pigs, BMS-181885 (10, 30, 100 and 300 microg kg(-1)) decreased the total carotid blood flow and conduction, exclusively at the expense of the arteriovenous anastomotic fraction as the capillary fraction did in fact increase. The highest dose (300 microg kg(-1)) produced a reduction of 52+/-6% from the baseline arteriovenous anastomotic flow. When carotid haemodynamic changes after a single 100 microg kg(-1)dose of BMS-181885 or sumatriptan were studied at different time-points, BMS-188185 had a longer duration of action. Both BMS-181885 (pD2:7.9+/-0.1; Emax:9+/-3% of the contraction to 100 mM K+) and sumatriptan (pD2:6.3+/-0.1; Emax:28+/-8% of the contraction to 100 mM K+) contracted the human isolated coronary artery. The above results suggest that (i) the longer-lasting vasoconstrictor action of BMS-181885 on porcine carotid arteriovenous anastomoses may be related to its reported slow dissociation from 5-HT1B/1D receptor, and (ii) BMS-181885 should be able to abort migraine headaches in patients. It will be interesting to find out whether these properties are clinically important so that the drug exhibits less headache recurrence and coronary side-effects than sumatriptan.

Effect of zopiclone on sleep, night-time ventilation, and daytime vigilance in upper airway resistance syndrome

We have assessed the effects of zopiclone (7.5 mg), a new cyclopyrrolone hypnotic drug, on ventilation, sleep parameters, and daytime vigilance in snorers with upper airway resistance syndrome (UARS). Using a randomized double-blind design, eight male patients with UARS took either oral zopiclone or a placebo each evening for seven consecutive days and then crossed over to the other drug after a 7 day placebo period. Polysomnography followed by a multiple sleep latency test (MSLT) was performed during the last night of each treatment period. Zopiclone produced significant improvements in the sleep efficiency index (total sleep time/time in bed) (placebo 84+/-15% versus zopiclone 91+/-7%) and average MSLT (placebo 10.3+/-3.7 min versus zopiclone 14.9+/-2.8 min), as well as nonsignificant improvements in sleep onset latency and total sleep time. It had no effect on sleep architecture or on the arousal index (placebo 17+/-8 arousals x h(-1) versus zopiclone 17+/-4 arousals x h[-1]). Furthermore, none of the respiratory parameters were significantly affected by zopiclone. In conclusion, zopiclone has no adverse effects on sleep architecture, respiratory parameters during sleep, and daytime sleepiness in patients with UARS.

EMD 57445, the selective sigma receptor ligand, has no effect on the 5-hydroxytryptamine system

The behavioral and biochemical effects of EMD 57445, a selective sigma receptor ligand with potential antipsychotic activity, on the 5-hydroxytryptamine (5-HT) system were studied in rats and mice. The drug influence was investigated in three behavioral tests: 8-OH-DPAT (5-HT1A agonist)-induced behavioral syndrome in rats, m-chlorophenylpiperazine (m-CPP, 5-HT1B agonist)-induced hypothermia in mice and L-5-hydroxytryptophan (L-5-HTP)-induced head twitches (5-HT2A stimulation) in rats. EMD 57445 did not show any activity in all three behavioral models. In biochemical studies, no changes in the 5-HT and 5-HIAA levels in rat brain cortex, nucleus accumbens, striatum, hypothalamus and hippocampus were found. The results indicate that EMD 57445 does not interact with 5-HT (5-HT1A, 5-HT1B, 5-HT2A) receptor subpopulations and does not affect 5-HT metabolism.

Pilot ascending dose tolerance study of parenterally administered 4-(2 hydroxyethyl)-1-piperazine ethane sulfonic acid (TVZ-7) in dogs

We report a pilot toxicity study in healthy beagle dogs which revealed no significant adverse events for TVZ-7 given at i.v. doses up to 520 mg/kg/day. All treated dogs displayed calm behavior and maintained normal clinical laboratory values throughout the study. Increased bone marrow hypercellularity and extramedullary hematopoiesis was also noted in these dogs. Three other dogs with advanced spontaneously occurring tumors have also been dosed. No serious adverse events were reported in any of the dogs. This pilot study suggests that 4-(2 Hydroxyethyl)-1-piperazine ethane sulfonic acid may be used safely in planned human clinical trials.

Cholesterol biosynthesis inhibited by BM15.766 induces holoprosencephaly in the rat

To confirm that blocking 7-dehydrocholesterol delta 7 reductase (7DHC reductase), as observed in Smith-Lemli-Opitz syndrome (SLOS), induces craniofacial defects, we tested BM15.766, which blocks 7DHC reductase but is chemically unrelated to the holoprosencephaly-inducing teratogen AY9944. Rats were given BM15.766 either in methylcellulose from days (D) 1 through D11 (3 treated groups: protocol A) or in olive oil from D4 through D7 (300 mg/kg/d: protocol B). The sera were sampled on D0, D3, and D5 or D6, D10, D14, and D21 to measure cholesterol and dehydrocholesterols in all groups and steroid hormones in protocol B. D21 fetuses showed the holoprosencephaly spectrum of malformations and the treated dams low cholesterol and accumulation of 7DHC, 8DHC, and trienols, as in SLOS-affected children. In the 3 dosage groups the malformations were dose-related and enzymatic cholesterol decreased to a plateau. The DHC reached 25-44% of the total sterols in the dams. In protocol B, one-third of the BM15.766-treated fetuses presented facial malformations and almost two-thirds pituitary agenesis. On D10, cholesterol reached a minimum and the DHC a maximum while estradiol 17 beta and progesterone were lowered, the latter decreasing in correlation with cholesterolemia. A sterol profile similar to that previously observed after AY9944 associated with a similarly high incidence of pituitary agenesis confirmed that time-limited inhibition of 7DHC reductase induces holoprosencephaly and that pituitary agenesis is the minor form of holoprosencephaly.

A newly synthesized bifunctional inhibitor, CKA1083, enhances adriamycin activity against human ovarian carcinoma cells

BACKGROUND

A newly synthesized drug, CKA1083 ((S)-N-[2-(4-benzyloxy-carbonylpiperazinyl)-1-(P-methoxybenzyl) ethyl]-N-methyl-N(5-isoquinolinesulfonamide)), has the same glutathione-S-transferase (GST)-binding site structure as W-77, a bifunctional inhibitor that enhances the cytotoxicity of Adriamycin for human ovarian carcinoma cells. We examined the effects of CKA1083 on the cytotoxicity of Adriamycin and the resistance of human ovarian carcinoma cells to this drug.

MATERIALS AND METHODS

We used GST-pi transfected cells and Adriamycin-sensitive or -resistant cells of human ovarian carcinoma. GST-pi activity, the intracellular Adriamycin content, and the cytotoxicity of Adriamycin in these cell lines in the presence or absence of CKA1083 were measured and compared to the findings obtained with W-77 or verapamil.

RESULTS

CKA1083 inhibited GST-pi activity in an uncompetitive manner and more strongly than W-77. It enhanced the cytotoxicity of Adriamycin for GST-pi transfected cells by about 3-times. Further, CKA1083 increased the intracellular Adriamycin content about 3-fold in two Adriamycin-resistant cell lines (NOS2AR and NOS3AR). CKA1083 (10 microM) reduced the IC50 of Adriamycin to 1/38 in NOS2AR cells and 1/21 in NOS3AR cells, and overcame Adriamycin resistance more effectively than both W-77 and verapamil.

CONCLUSIONS

CKA1083 enhanced the antitumor effect of Adriamycin more than W-77 by inhibiting both GST activity and P-glycoprotein.

Pathogenesis of malformations in a rodent model for Smith-Lemli-Opitz syndrome

The fact that Smith-Lemli-Opitz syndrome (SLOS), a syndrome comprising major malformations involving a number of organ systems, results from an abnormality in cholesterol biosynthesis, was discovered only recently. Utilizing a drug (BM 15.766) to inhibit the same step in cholesterol biosynthesis as is abnormal in those affected with SLOS, we have developed a rat model that presents with abnormalities observed as early as gestational day 12 that appear to be consistent with some of those subsequent malformations that comprise the human syndrome. Abnormalities of the brain and face include deficiency in the midline region of the upper face, narrowing of the forebrain hemispheres and of the cerebral aqueduct, and deficiency in the developing lower jaw. Associated pathogenesis, as observed on gestational day 11 in histological sections and with scanning electron microscopy, involves abnormal cell populations at the rim of the developing forebrain and in the alar plate of the lower midbrain and hind-brain. The affected cells appear abnormally rounded up, having apparently lost their normal cell contacts. The potential basis for the selective vulnerability of this cell population and the impact of its vulnerability relative to subsequent dysmorphogenesis is discussed.

4-Aryl-1-piperazinylalkyl derivatives of 1,2,3,4-tetrahydro-beta-carboline ring system. Synthesis and preliminary in vivo studies

Three series of compounds containing a 4-aryl-1-piperazinylalkyl fragment attached to a different position of the indole (A) or 1,2,3,4-tetrahydro-beta-carboline (B, C) have been prepared. The quantitative relationship between the structure of some derivatives and their sedative effect was found using the Free-Wilson approach.

Effects of psychotropic drugs on aldo-keto reductase activity in rat ovary and adrenal gland

We investigated the effects of minor and major tranquilizers on ovarian and adrenal aldo-keto reductase activity towards five substrates in relation to ovulation in mature cycling rats. Nitrazepam (NZP) did not alter ovarian and adrenal weights or body weight, although ovulation was inhibited at 5 and 10 mg/kg. NZP decreased ovarian 13,14-dihydro-15-ketoprostaglandin F2 alpha (15KD-PGF2 alpha) and 4-benzoylpyridine (4BP) reducing activities. None of the doses of zopiclone (ZPC) influenced uterine and adrenal weights or body weight, but it increased ovarian weight at 10 mg/kg. No significant effects of ZPC on ovarian aldo-keto reductase activity were observed. NZP had inhibitory effects on adrenal aldo-keto reductase activity, whereas ZPC had a stimulatory effect. Chlorpromazine (CPZ) did not alter ovarian or adrenal weight, whereas the estrous cycles were abolished at 5 and 10 mg/kg. Reserpine (RSP) decreased ovarian weight and completely inhibited ovulation at 5 and 10 mg/kg, but it increased adrenal weight. Both CPZ and RSP decreased, dose dependently, ovarian aldo-keto reductase activity towards five substrates in agreement with the inhibition of ovulation. On the other hand, differences were found between the effects of CPZ and RSP on adrenal aldo-keto reductase activity. CPZ significantly increased 4BP reducing activity at 5 and 10 mg/kg, although no significant changes were observed in the other four reducing activities. RSP decreased 15KD-PGF2 alpha reducing activity in a dose-dependent manner, whereas the other four activities did not change.

The experimental antipsychotic agent 1192U90 targets tapetum lucidum in canine eyes

To assess the potential adverse effects in people of the antipsychotic agent 1192U90, we dosed mice, rats, beagles, and cynomolgus monkeys for up to 3 mo. In dogs, but not the other species, 1192U90 caused ocular changes detectable ophthalmoscopically as loss of tapetal reflectivity, altered tapetal color, and the appearance of black pigmentation on the tapetal fundus. Eyes from affected dogs had atrophic tapeta lucidum due to cell loss. Rodlets in remaining tapetal cells were separated by electron-lucent spaces or finely granular material, varied in size and shape, and often contained irregularly shaped electron-dense inclusions. Nontapetal ocular structures were unaffected. Because 1192U90 caused no ocular changes in nontapetal species, we hypothesized that it targeted only tapetum lucidum and spared other ocular structures. We tried to test this hypothesis by dosing congenitally atapetal dogs; however, although these dogs were ophthalmoscopically "atapetal," they had scattered tapetal cells visible by electron microscopy, and these tapetal cells had ultrastructural changes indistinguishable from those that occurred in treated normal-eyed dogs. Tapetal degeneration caused by 1192U90 resembled that described in hereditary tapetal degeneration in beagles. That 1192U90 caused no ocular changes in nontapetal species suggests that the ocular changes in dogs do not imply a risk for humans, whose eyes also lack a tapetum lucidum.

Lazaroids inhibit proliferation of cultured human astrocytoma cells

Lazaroids (or 21-aminosteroids) are potent lipid peroxidation inhibitors and are more potent antioxidants than steroids which have been shown to suppress tumor proliferation. The effects of two lazaroid compounds (U-75389G and U-83836E) were tested on the proliferation of a human brain astrocytoma cell line U-373MG. Both lazaroids had dose-dependent growth-inhibitory effects on the proliferation of U-373MG. For purposes of comparison, two steroids (methylprednisolone and dexamethasone) and a highly potent antioxidant (alpha-tocopherol) were tested under similar experimental conditions and were found to have antiproliferative effects as well, although at higher dose ranges. As cell growth-inhibitors, lazaroids are more effective than alpha-tocopherol while they are advantageous over glucocorticoids for their actions are devoid of the usual glucocorticoid side-effects.

Structure-activity relationship in a series of new 1-(2-pyrimidinyl)piperazine derivatives with hypnotic activity

Preparation, biological properties and QSAR of new derivatives of 1-[4-(2-pyrimidinyl)-1-piperazinyl]-1, 3-butandione (11-13, and 15-18) and 3-[4-(2-pirimidinyl)-1-piperazinyl]-3-oxopropanoate (20-22) exhibiting hypnotic activity in mice are reported. The best therapeutic indices (TI = LD50/ED50) 4.7 and 9.4 for po and ip administration, respectively, were found for 1-[4-(2-pyrimidinyl)-1-piperazinyl]-2-n-pentyl-1,3-butandione (15). QSAR studies showed that the biological activity grows initially with an increase in lipophilicity to drop dramatically for log P > 2.5.

[A 13-week oral toxicity study of prulifloxacin (NM441) in dogs followed by a 5-week recovery test]

A repeated dose toxicity study of prulifloxacin, a new antibacterial agent, was conducted in beagle dogs. Male and female dogs were given the test material orally for 13 weeks at doses of 0 (control), 20, 100 and 500 mg/kg. After discontinuation of the treatment, a 5-week recovery test was also conducted. Vomiting, salivation and decreased body weight gain or reduced body weight were seen in the 100 and 500 mg/kg groups. In the 500 mg/kg group, tremor, paresis of posterior limb associated with prone or sitting position and decreased food consumption were also observed. There were no treatment-related effects on survival and water consumption. Ophthalmoscopic, electrocardiographic and hematologic examinations, and urinalysis failed to show any abnormalities attributable to the treatment. Blood chemical examination showed increased GPT and decreased beta- and gamma-globulins in the 100 and 500 mg/kg groups, and increased GOT in the 500 mg/kg group. In pathological examination, cavitations and erosions were seen in the humeral and femoral articular cartilages in the 100 and 500 mg/kg groups. The above-mentioned changes were satisfactorily reversible except for erosions in the humeral and femoral articular cartilages in the 100 and 500 mg/kg groups. No toxicological findings were seen in the 20 mg/kg group. The results show that the NOAEL of prulifloxacin is 20 mg/kg for 13-week repeated dose toxicity in dogs.

[Reproductive and developmental toxicity studies of prulifloxacin (NM441)(2)--A teratogenicity study in rats by oral administration]

A study of the effect of prulifloxacin, a new antibacterial agent, during the period of organogenesis was conducted in Sprague-Dawley rats. Female rats were given prulifloxacin orally at dose levels of 0 (control), 30, 300, and 3000 mg/kg from day 7 to day 17 of pregnancy. Twenty-four or twenty-five female rats per dose level were sacrificed on day 20 of pregnancy for examination of their fetuses, and the pregnant rats (12-15 per dose levels) were allowed to deliver naturally for postnatal examination of their offspring. In the 300 or 3000 mg/kg groups, the food consumption decreased and water consumption increased in the dams. In the 3000 mg/kg group, the body weight gain was suppressed in the dams. In the 300 and 3000 mg/kg groups, the weights of cecum increased and the enlargement of cecum was observed. In the 3000 mg/kg group, white spots and rough surface of the kidney and renal tubular nephrosis with crystalline substance were observed and the weight of the kidney increased in the dams, and the body weight decreased and retarded ossifications in the fetuses. Prulifloxacin had no effect on the number of corpora lutea and implantations, or on fetal mortality, sex ratio, or external and visceral development of the fetuses. Prulifloxacin also did not affect delivery and the number of live newborns and birth index, or have any adverse effects on the postnatal development of the first generation offspring (F1) such as differentiation, functional development, emotionality, motor ability, learning ability or reproductive performance. Prulifloxacin also had no adverse effects of the second generation offspring (F2). These results show that the NOAEL of prulifloxacin are 30 mg/kg for general toxicity in mother animals, 3000 mg/kg for pregnancy and delivery of mother animals and 300 mg/kg for development of their offspring.

[Reproductive and developmental toxicity studies of prulifloxacin (NM441)(4)--A perinatal and postnatal study in rats by oral administration]

A peri- and postnatal study of prulifloxacin, a new antibacterial agent, was conducted in Sprague-Dawley rats. Female rats were given prulifloxacin orally at dose levels of 0 (control), 30, 100 and 300 mg/kg from day 17 of pregnancy to day 21 after delivery. All pregnant rats were allowed to deliver naturally for postnatal examination of their offspring. Food consumption in the period of pregnancy decreased in the dams given 100 and 300 mg/kg, and food and water consumption during lactational period increased in the dams given 300 mg/kg. The weight of the cecum of the dams increased in 100 and 300 mg/kg groups, and these doses caused enlargement of the cecum. Prulifloxacin had no effects on general sign, delivery, nursing, body weight gain, and kidney. Prulifloxacin also did not affect the number of live newborns and birth index, and have any adverse effects on the postnatal development of the first generation offspring (F1) such as differentiation, functional development, emotionality, motor ability, learning ability and reproductive performance. Prulifloxacin also had no adverse effects on the second generation offspring (F2). These results show that the NOAEL of prulifloxacin are 30 mg/kg for general toxicity in mother animals, 300 mg/kg for pregnancy and delivery of mother animals and development of their offspring.

[A 13-week oral toxicity study of prulifloxacin (NM441) in rats followed by a 5-week recovery test]

A repeated dose toxicity study of prulifloxacin, a new antibacterial agent, was conducted in Sprague-Dawley rats. Male and female rats were given the test material orally for 13 weeks at doses of 0 (control), 30, 170 and 1000 mg/kg. After discontinuation of the treatment, a 5-week recovery test was also conducted. Salivation, soft feces, reduced body weight gain and increased water consumption were seen in the 1000 mg/kg group. There were no treatment-related effects on survival and food consumption. Ophthalmoscopic and hematologic examinations failed to show any abnormalities attributable to the treatment. Urinalysis revealed increased urine volume and decreased K+ excretion in the 1000 mg/kg group. Blood chemical examination showed increased BUN, decreased triglyceride, K+, Cl- and total protein in the 1000 mg/kg group. Pathological changes caused by the treatment were as follows. Renal tubular nephrosis with crystalline substance was observed in the 170 and 1000 mg/kg groups. Renal weight was increased and crystalline substance was noted in the lumen of the urinary bladder in the 1000 mg/kg group. Cecal distention with increased its organ weight was observed in all dose groups and swelling of its absorptive cells was seen in the 170 and 1000 mg/kg groups. Swelling of jejunal goblet cells was observed in the 1000 mg/kg group. In femoral articular cartilage, focal accumulation of chondrocytes, small cavities and proliferation of fibrous tissue were seen in the 170 and 1000 mg/kg groups. The above-mentioned changes were reversible except for renal tubular nephrosis and cecal distention with its increased organ weight, of which the degree and frequency, however, were lowered. The cecal distention in the 30 mg/kg group was considered to be attributable to the pharmacological effect of the test material. The results show that the NOAEL of prulifloxacin is 30 mg/kg for 13-week repeated dose toxicity in rats.