The use of lipid emulsions for the i.v. administration of a new water soluble polyene antibiotic, SPK-843.

Venous tolerance of a new water soluble polyene antibiotic, SPK-843, in 5% glucose solution for infusion is low in laboratory animals. The use of Intralipid 10% emulsion was therefore proposed, in which the antibiotic remained chemically stable for at least 2 h in a mildly acid or nearly neutral environment and at concentrations of 0.1-0.5 mg/mL, producing no alterations in the emulsion structure. Tolerance was assessed through repeated infusions in the ear marginal vein of rabbits and was found much more satisfactory than the tolerance observed when the vehicle used was 5% glucose solution. The study of the effect of some variables (concentration, volume infused, dose per kg) on venous toxicity offered the possibility to plan optimal administration conditions of presumed therapeutic doses.

Effects of mepartricin on estradiol and testosterone serum levels and on prostatic estrogen, androgen and adrenergic receptor concentrations in adult rats.

The effects induced by oral administration of 0, 5 and 20 mg of meparticin kg(-1)of body weight for 28 days (group 1, 2 and 3, respectively) upon prostatic estrogen, androgen, alpha(1)- and beta-adrenergic receptor concentrations and on estradiol and testosterone serum levels in adult male rats were studied. The effects produced by mepartricin treatments on the weight and dimension of the gland were investigated. Both mepartricin dosages induced significant decreases (P< 0.05) of the absolute and relative weights and of the dimensions of the prostate. A significant dose-dependent decrease (P< 0.05) in estradiol serum levels was observed in treated rats, whereas no significant modifications were found in testosterone serum levels. As far as prostatic steroid receptor concentrations were concerned, a significant (P< 0.05) decrease in estrogen receptor number was observed in both treated groups, whilst a significant increase (P< 0.05) of androgen receptor concentrations was recorded only in rats treated with 20 mg mepartricin kg(-1). Conversely, a dose-dependent up-regulation of both prostatic alpha(1)- and beta-AR was found. Data obtained suggest that the prostatic alpha(1)-AR expression may be strongly influenced by estrogen deprivation (mepartricin treatment), therefore the combination of estrogen suppression (mepartricin) and adrenergic suppression (alpha(1)-AR blockers) may be suggested as a possible pharmacotherapeutic strategy for the treatment of benign prostatic hyperplasia.

Analgesic effect of bisphosphonates in mice.

Bisphosphonates are analogues of inorganic pyrophosphate and are inhibitors of bone resorption. Many derivatives have been developed for the treatment of enhanced bone resorption; several reports reveal that treatment with bisphosphonates is able to reduce the pain associated with different painful diseases. This study tested the antinociceptive action of four bisphosphonates, clodronate, alendronate, pamidronate and etidronate, in comparison with that of morphine and acetylsalicylic acid using two algesimetric tests in mice, tail-flick and writhing tests. In the tail-flick test, after intravenous (i.v.) injection, a dose-dependent antinociception was present after pamidronate, clodronate and acetylsalicylic acid whereas etidronate and alendronate produced an analgesic effect only with the highest dose tested. We also studied the central effect of clodronate and pamidronate and, after intracerebroventricular injection, both bisphosphonates showed a dose-dependent antinociceptive effect. In the writhing test clodronate and pamidronate showed a statistically significant antinociceptive action after i.v. and intramuscular administration. To verify if clodronate and pamidronate could modulate the peripheral opioid receptors we evaluated the gastrointestinal transit time in mice, but we did not find any effect on the gastrointestinal motility. These data indicate that clodronate and pamidronate present a central and peripheral antinociceptive effect; however, the main mechanism cannot be determined from the present data. We discuss the possible pharmacological hypothesis to interpret the present results. The findings suggest a pharmacological role of the bisphosphonates in the modulation of antinociception even in acute conditions not related to accelerated osteolytic and inflammatory response, with a possible clinical application to control pain.

Pharmacokinetics in rats of n-dimethylaminoacetyl-partricin a 2-dimethylaminoethylamide diascorbate (spk-843).

Single- and multiple-administration trials in rats were performed in this study to assess the serum and tissue concentrations of SPK-843 (N-dimethylaminoacetyl-partricin A 2-dimethylaminoethylamide diascorbate), a new polyene antibiotic with a heptaene structure. A dose of 1.25 mg/kg (roughly 1 mg/kg of free base) by intravenous route was used both for the single- and multiple-administration trials. The single-administration trial was carried out in comparison with amphotericin B (AmB) at intravenous doses of 1 mg/kg. Plasma samples were drawn at intervals from 15 min to 96 h after injection. The elimination half-lives were 22.15 and 18.15 h, and the area under the curve to infinity (AUC(0-infinity)) values were 35.52 and 10.33 microg.h.ml(-1), respectively, for SPK-843 and AmB. Both drugs showed an extensive tissue distribution, with higher uptake by the kidneys, followed by the liver, spleen and lungs for SPK-843, and higher uptake by the spleen, followed by the lungs, liver and kidneys for AmB. The multiple-administration trial (1.25 mg/kg/day for 7 days) led to sustained serum and tissue concentrations. On the seventh day, the rats were bled at intervals from 5 min to 96 h after dosing. The serum elimination half-life and AUC(0-infinity) values were roughly twice those of the single-dose study (41.4 h and 72.1 microg.h.ml(-1), respectively). Also, the half-lifes and AUCs from 0 to infinity of tissues were greater than those in the single-dose trial.

Binding of mepartricin to sex hormones, a key factor of its activity on benign prostatic hyperplasia.

Androgens and estrogens, mainly testosterone (TES) and dihydrotestosterone (DHT) and 17 beta-estradiol (EST), are widely recognized to regulate the prostate growth and their imbalance with aging, leading to reduction of androgens and relative increase of estrogens, may be responsible for the development of benign prostatic hyperplasia (BPH). Mepartricin (CAS 11121-32-7), a polyene drug for medical treatment of BPH, was assayed in vitro for its ability to bind with 14C-labelled sex hormones, by incubation in buffered saline, serum and bile, followed by centrifugation and dosing of the radioactivity in the supernatant. It proved effective in complexing up to 90% of TES and DHT in buffered saline and up to 80% of EST in bile. Due to minimal absorption of oral mepartricin and to much higher enterohepatic circulation for estrogens than for androgens, the binding effect of mepartricin on EST in the gut should be of particular pharmacological relevance to explain its mechanism of action on BPH.

Comparative pharmacokinetics of three preparations of the new antifungal SPK-843.

The pharmacokinetics and tissue distribution of three preparations of SPK-843 (N-dimethylaminoacetyl-partricin A 2-dimethylaminoethylamide diascorbate), a new polyene antibiotic with a heptaene structure, were compared in rats after a single 1.25 mg/kg intravenous administration. Blood and tissue samples were obtained at 0.25-96 h after injection. The serum pharmacokinetics of the three dosage forms of the antibiotic, A (5% glucose solution), B (10% lipid emulsion at pH 5.3) and C (10% lipid emulsion at pH 7.5), did not show large differences, the half-lives being 22.2, 26.5 and 23.2 h and the AUC(0-infinity) 35.5, 40 and 44.8 microg.h.ml(-1) for preparations A, B and C, respectively. The tissue uptake of the two lipid-based preparations, particularly the spleen uptake, was greater than that of the glucose preparation, suggesting an active role of the lipid vehicle in tissue distribution.

Pharmacokinetics of a new derivative of partricin A (SPA-S-753) in rodents.

Pharmacokinetics of a new semisynthetic polyene antibiotic (N-dimethylaminoacetyl-partricin A 2-dimethylaminoethylamide) in the form of its diaspartate salt (code SPA-S-753) was studied in rats and mice following intravenous injection and in rats following oral administration at different dose levels. In rats the urinary and biliary recovery after intravenous administration was also determined. Rats and mice received a single intravenous injection of 1.25 and 2.5 mg/kg of SPA-S-753 (about 1-2 mg/kg of free base) or 1 mg/kg of amphotericin B as reference drug. Blood samples were obtained at 5 min to 96 h after injection. The half-lives at the elimination phase in serum were 21.3, 26.5, 10.8 h in rats and 11.7, 13.7, 19.8 h in mice, respectively, for 1.25 and 2.5 mg/kg of SPA-S-753 and 1 mg/kg of amphotericin B. The values of AUC(0-infinity) for SPA-S-753 were about 5 times higher in rats and twice higher in mice than those for amphotericin B. Rats received also a single oral dose of 200 or 500 mg/kg of SPA-S-753. Serum samples were obtained at 0.5-96 h after dosing. The compound is poorly absorbed by the oral route. The mean cumulative urinary recovery of SPA-S-753 at 48 h after intravenous injection of 1.25 mg/kg in rats accounts only for 0.5% of the dose, while the cumulative recovery from the bile at 10 h after 2.5 mg/kg i.v. administration in rats accounts for 5.5% of the dose.

Pharmacokinetics and tissue distribution of rifametane, a new 3-azinomethyl-rifamycin derivative, in several animal species.

Single and repeated dose experiments in mice, rats, dogs and monkeys are reported in this study to assess the pharmacokinetics and tissue distribution of rifametane, a new semi-synthetic rifamycin with the chemical formula 3-[(1-diethylaminoethylidene)azinomethyl]rifamycin SV (CAS 94168-98-6, SPA-S-565). All the kinetic tests were carried out in comparison with known rifamycin derivatives, as rifampicin (CAS 13292-46-1) or rifamycin SV (CAS 6998-60-3). Mice received single i.v. and oral administration of 10 mg/kg of rifametane or of rifampicin and serum samples were obtained up to 96 h after dosing. The two antibiotics showed similar peak of serum concentrations, but rifametane showed a longer half-life and higher AUC values. In an additional experiment, the tissue/serum ratio after the 10 mg/kg oral dose was lower than unity for lungs and kidneys, while the liver/serum ratio exceeded the unity at all sampling times. After 4 weeks of once weekly administration measurable serum and tissue concentrations were observed, and after twice weekly administration for the same time period some blood and tissue accumulation was seen. Rats were treated with a single intravenous injection of 20 mg/kg of rifametane or rifampicin and with single oral or i.m. administration of 60 mg/kg of rifametane or reference standards (rifampicin and rifamycin SV resp.), in two separate trials. The serum half-life of the test antibiotic after i.v. dose was 6 times longer than that of rifampicin and the serum concentrations of rifametane after oral and i.m. doses were higher and longer-lasting than those of the reference compounds. Repeated daily administrations of rifametane at three dose levels (3, 10, 30 mg/kg p.o.) for 4 weeks induced very high serum and liver concentrations. Dogs received a single oral dose of 1.25 mg/kg of rifametane or 2.5 mg/kg of rifampicin. The serum half-life of rifametane resulted 3 times longer than that of rifampicin. Remarkable serum and tissue concentrations were observed after 3-4 weeks of daily oral administration of rifametane at 3, 10, 30 mg/kg dose. Monkeys were given single oral or i.m. administration of 30 mg/kg of rifametane or reference standards (oral rifampicin and i.m. rifamycin SV). The serum concentrations after rifametane were higher and more sustained than those of reference compounds and the half-lives of the test antibiotic were about 2.5 (p.o.) to 6 times (i.m.) longer. The urine excretion of rifametane after a single intravenous dose in rats and a single oral dose in dogs was very low, while rifampicin had a little higher urine concentrations.

Anticandidal activity of SPA-S-843, a new polyenic drug.

The activity of a new, soluble and stable polyene (SPA-S-843) against Candida albicans was assessed by contact and culture tests and by inhibition of germ-tube formation. The drug demonstrated a higher contact activity and lower MICs than amphotericin B. This antimicrobial activity was more evident under acid pH and low ionic strength. In addition, the ability of SPA-S-843 to inhibit Candida sp. conversion from yeast to mycelial form was evident at low drug concentrations (0.25-0.62 mg/L).

Overview of SPA-S-843 in vitro activity against filamentous fungi.

In this study, we investigated the in vitro antifungal activity of a new water-soluble partricin A derivative, N-dimethylaminoacetyl-partricin A 2-dimethylaminoethylamide diascorbate, coded SPA-843, currently developed by Società Prodotti Antibiotici. The activity of SPA-S-843 was compared to that of amphotericin B against 13 strains of Aspergillus spp., 4 strains of Mucor sp., 4 strains of Rhizopus oryzae, 2 strains Paecilomyces variotii, 5 strains of Penicillium spp., 1 strain of Sporothrix schenkii, 7 strains of Trichophyton spp. and 2 strains of Microsporum spp.; the minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) were measured for all the organisms. The in vitro susceptibility testing method employed was an adaptation of the macrodilution reference method for yeasts as described in the National Committee for Clinical Laboratory Standards document M27-A. The in vitro inhibitory activities of SPA-S-843 and amphotericin B against the fungi were evaluated in RPMI-1640 supplemented with L-glutamine and buffered with morpholinepropanesulfonic acid, while the in vitro fungicidal activities were determined by subculturing 0.1 ml from all tubes with no visible growth onto drug-free Sabouraud dextrose agar plates. Comparison with amphotericin B showed that the in vitro inhibitory activity of SPA-S-843 against Aspergillus spp. was better than that of amphotericin B and similar against R. oryzae, P. variotii, Penicillium spp. and S. schenkii. Amphotericin B presented geometric means (GM) of the MICs lower than those of SPA-S-843 against Mucor sp., Microsporum spp. and Trichophyton spp. SPA-S-843 was most fungicidal against Mucor sp. and P. variotii; SPA-S-843 and amphotericin B showed the same fungicidal activity against Aspergillus spp. (GM of the MFCs 12.53 microg/ml), Penicillium spp. (about 12 microg/ml) and S. schenkii (MFC 19.2 microg/ml). Amphotericin B presented GM of the MFC values lower than those of SPA-S-843 against R. oryzae, Microsporum spp. and Trichophyton spp.

Phase I pharmacokinetic study of a new 3-azinomethyl-rifamycin (rifametane) as compared to rifampicin.

An open randomized cross-over study was conducted in 8 healthy male volunteers to study the pharmacokinetic pattern and the safety of a 300-mg single oral dose of a new 3-azinomethyl-rifamycin (USAN rifametane, SPA-S-565) compared with 300 mg of conventional rifampicin. The pharmacokinetic profiles of rifametane were significantly more favorable than those of rifampicin. The serum peak value was 7.82 microg/ml for rifametane and 4.04 microg/ml for rifampicin (p < 0.001); the elimination half-life was 10.58 h for rifametane and 1.89 h for rifampicin (p < 0.001); area under the serum concentration curve from 0 to infinity was 142.3 microg.h/ml for rifametane and 19.9 microg.h/ml for rifampicin (p < 0.001); the mean residence time was 18.05 h for rifametane and 3.93 h for rifampicin (p < 0.001). Rifametane showed a good safety profile after the 300-mg single oral dose. Three volunteers developed a mild headache, metallic taste and slightly elevated temperature for 3-4 h, which subsided without medication. Clinically or statistically significant changes in laboratory parameters were not found between baseline and posttreatment values.

Pharmacokinetic profile of a new 3-azinomethyl rifamycin (SPA-S-565) in volunteers as compared with conventional rifampicin.

The pharmacokinetics and tolerance of a single oral dose (150 mg) of a new 3-azinomethyl rifamycin (SPA-S-565, USAN rifametane) was compared with 150 mg of conventional rifampicin in six healthy volunteers. The mean maximum concentration (Cmax) of SPA-S-565 was 3.94 +/- 0.26 micrograms/ml, and resulted significantly higher as compared with the Cmax after rifampicin, which was 2.89 +/- 0.20 micrograms/ml. The mean maximum time (tmax) for SPA-S-565 was 2.1 +/- 0.3 h as compared with that of rifampicin, which was 1.6 +/- 0.3 h, the difference between these values not being statistically significant. The elimination half-life (t1/2) of SPA-S-565 was 17.5 +/- 2.6 h in contrast to the half-life of 2.8 +/- 0.26 h seen with rifampicin; the difference was found to be highly significant. The mean area under the serum concentration curve from 0 to the last detectable concentration (AUC0-t) and the mean area under the serum concentration-versus-time curve from 0 to infinity (AUC0-infinity) of SPA-S-565 were almost six times than those obtained with conventional rifampicin. The differences between the two compounds were highly significant. In all cases except one volunteer all the biochemical parameters remained within normal range following single oral dose administration of SPA-S-565. In one volunteer, although there was a slight rise in serum alkaline phosphatase above the normal range, the original value itself was at the very upper limit of the normal range (i.e., 80 IU/L). Although there was a significant increase in the levels of serum alkaline phosphatase, serum gamma-glutamyl transpeptidase (GGTP) and serum amylase levels, 24 h following the administration of SPA-S-565 these levels remained within the normal range.

In vitro activity of a new polyene, SPA-S-843, against yeasts.

The in vitro activity of a new water-soluble polyene, SPA-S-843, was evaluated against 116 strains of Candida, Cryptococcus, and Saccharomyces spp. and compared with that of amphotericin B. SPA-S-843 demonstrated better inhibitory activity against all of the yeasts examined and better fungicidal activity against Candida albicans, Candida glabrata, Candida krusei, and Candida tropicalis than did amphotericin B.

In vivo and in vitro antifungal activity of the polyene derivative SPA-S-753 against encapsulated form of Cryptococcus neoformans.

The in vitro and in vivo activity of SPA-S-753 (N-dimethylaminoacetyl-partricin A 2-dimethylaminoethylamide diaspartate), a new water soluble polyene, was compared with amphotericin B against Cryptococcus neoformans in encapsulated (K) and nonencapsulated (N) morphological forms. In vitro tests against 17 isolates of C. neoformans (in K or N form) showed that SPA-S-753 activity is about ten times higher than that of amphotericin B. In direct contact tests the SPA-S-753 cytocidal action was significantly higher than that of amphotericin B; the K cells are, however, less sensitive to the cytocidal action exerted by the two polyenes even when using concentrations 4-fold higher than those used against the N cells and they present a smaller potassium ion release. The cytocidal activity of the two polyenes is favoured by a low electrolyte concentration and an acid pH. SPA-S-753 microbicidal activity by contact in vivo, in mice infected with C. neoformans N cells by i.p. route, is more powerful than that of amphotericin B. In protection tests in mice infected with 10 LD50 of C. neoformans K cells, SPA-S-753 action is again more powerful, but not to a significant degree, than that of amphotericin B. In conclusion, both substances showed a reduced in vitro and in vivo activity against C. neoformans in the K morphological form. Nevertheless our results demonstrate that SPA-S-753 exerts an antifungal overall activity that is more effective than that of amphotericin B under similar experimental conditions.

Comparative anti-gonococcal activity of S-565, a new rifamycin.

The in vitro activity of S-565, a semi-synthetic rifamycin chemically related to rifampicin but with a longer half-life, has been compared with that of rifampicin, ciprofloxacin, spectinomycin, azithromycin and amoxycillin against Neisseria gonorrhoeae. Modal MICs against 20 strains were 0.13 mg/l for rifampicin and 0.5 mg/l for S-565. There was cross-resistance between the two rifamycins, and each selected for resistance at similar rates. In a time-kill study, S-565 was more rapidly bactericidal than rifampicin at x 1 and x 2 MIC.

Analgesic activity of the lysozyme peptide N-(N-L-threonyl-L-alpha-aspartyl)-L-tyrosine in the monkey and the dog.

N-(N-L-Threonyl-L-alpha-aspartyl)-L-tyrosine (CAS 115053-54-8, SPA-S-646) was originally derived from lysozyme. It has previously been found to have analgesic properties following oral and intravenous administration to laboratory rodents. In the rhesus monkey, intramuscular administration of SPA-S-646 caused a dose-related analgesia. This effect was not seen following oral administration, but when given via the rectum, analgesia was again observed. In the dog, a single dose of 50 mg/kg was active by the intramuscular route but not the oral route. It is thought that unlike the rat, the digestive systems of the rhesus monkey and the dog degrade the tripeptide into inactive constituents.

Complex partial status epilepticus simulating an ischemic insult: case report.

A patient presenting complex partial status epilepticus (CPSE) had a clinical history and neurological picture on admission that mimicked a cerebrovascular insult. On admission she was confused and totally unresponsive to verbal stimuli. EEG showed high voltage paroxysmal activity on the left hemisphere, prominent on the temporoccipital leads and tending to spread to the opposite regions. Intravenous diazepam led to resolution of the clinical and EEG picture within 24 hours, only a medium voltage slow wave focus being present on the left temporal regions. CPSE should be considered whenever a prolonged impairment of consciousness is present. Only accurate EEG recordings permit correct diagnosis in doubtful cases.

Antinociceptive properties of lysozyme fragments.

The in vitro digestion of hen egg white lysozyme with artificial gastric juice gave a complex mixture of peptides, from which a peptide corresponding to the aminoacid sequence 39-53 was isolated. Its further hydrolysis with artificial enteric juice gave two smaller fragments having the aminoacid sequence 39-45 and 46-53 respectively. These products, like lysozyme, showed antinociceptive activity in rats against foot hyperalgesia induced by a subplantar injection of brewer's yeast.

The antibacterial activity of a new 3-azinomethyl-rifamycin.

The new 3-azinomethyl-rifamycin, SPA-S-565, was shown to exert an effective antibacterial activity in vitro comparable to that of rifampicin. In fact, the antibacterial activity of SPA-S-565 against numerous Gram-positive cocci belonging to Staphylococcus and Streptococcus species as well as against 20 strains of Mycobacterium tuberculosis, was similar to that of rifampicin. In Swiss albino mice intraperitoneally infected with Staphylococcus aureus Oxford strain or Streptococcus pyogenes, the protective activity of SPA-S-565 and rifampicin was quite remarkable, and no significant difference was noted between the two antibiotics. In M. tuberculosis-infected mice treated with the antibacterial agents every seven days, the protection exerted by SPA-S-565 was significantly greater than that exerted by rifampicin.

New long-acting 3-azinomethyl-rifamycins.

A number of basic 3-azinomethyl-rifamycins have been prepared. Their synthesis and antibacterial activity in vitro are reported, as well as the preliminary pharmacokinetic data. While the antimicrobial activity is comparable with that of rifampicin, serum levels in mice are much longer lasting. One of the compounds was selected for further studies.