Pharmacokinetics of sulfamonomethoxine in tongue sole (Cynoglossus semilaevis) after intravenous and oral administration

The pharmacokinetic profiles of sulfamonomethoxine (SMM) were investigated in flatfish tongue soles in the present study. After a single injection of SMM (40 mg/kg BW) to caudal vein of tongue sole at 20 °C, plasma drug concentration versus time data were best fitted to a three-compartment model, characterized with 0.2, 5.7, and 80.4 h for the half-life (t 1/2) of fast distribution, slow distribution, and elimination, respectively. The apparent volume of distribution was 0.1 L/kg, and the body clearance was 0.03 L/h/kg. After oral administration of SMM (200 mg/kg BW) to tongue soles at 20 °C, plasma drug concentrations were best fitted to a two-compartment model, of which the mean half-life of absorption (t 1/2ka) and elimination (t 1/2β ) were 1.7 and 95.7 h, respectively. The maximal absorption concentration (C max) was estimated as 58 mg/L at 2.5 h, and the mean systemic bioavailability (F) was 39.5 % in tongue soles after oral administration.

Absorbability of sulphamonomethoxine and sulphadimethoxine administered via food of laying hens

Sulphamonomethoxine (SMM) or sulphadimethoxine (SDM) were fed each to four laying hens at a dietary content of 400 p.p.m. 1000 p.p.m. of chromic oxide were supplemented to the experimental diets as an indicator for the absorbability in the gastrointestinal tract. SMM and SDM contents (p.p.m.) in the large intestine, determined 16 h after the start of feeding, were measured by HPLC. Average amounts of SMM and SDM in the dry matter of the large intestine were 12.3 and 30.2 p.p.m., respectively. The absorption ratios of SMM and SDM administered via the food were calculated to be 96.9 and 92.5%, respectively.

Depletion of dietary sulphamonomethoxine and sulphadimethoxine from various tissues of laying hens

Sulphamonomethoxine (SMM) or sulphadimethoxine (SDM) was fed to laying hens at 400 mg/kg diet for 5 successive days. After withdrawal of the drugs, contents (mg/kg) of SMM and SDM in the blood, kidney, liver, ovary, muscle and adipose tissue were determined by HPLC. 2. The disappearance of dietary SMM and SDM from the tissues of laying hens was rapid and, except for the liver, was very similar in all tissues. 3. A common biological half-life (t1/2) of SMM in the above 6 tissues was estimated to be 5.2 h. The t1/2 of SDM in the liver was 6.9 h, significantly longer than that of 4.4 h in the other 5 tissues. The values were much shorter than 51/2 (reported elsewhere) for other drugs. 4. Comparing the data found in this study with those obtained from previous papers, the depletion velocities of SMM and SDM from the hen's body were much faster than those from albumen in egg. The reason for this is probably related to the longer time period over which albumen formation occurs.

Comparative plasma and tissue pharmacokinetics and drug residue profiles of different chemotherapeutants in fowls and rabbits

Blood and tissue pharmacokinetics and drug residue profiles of six chemotherapeutants were studied. Ceftriaxone (CEF), intravenously at 50 mg/kg, sulfamonomethoxine (SMM) and sulfaquinoxaline (SQ), orally at 200 mg/kg, and olaquindox (OLA), orally at 50 mg/kg, were administered to young broilers. Penicillin (PEN), intramuscularly at 200,000 U/kg, and albendazole (ALB), orally at 20 mg/kg, were given to rabbits. For each drug, 13-18 groups (n = 5-10 individuals/group) of the dosed animals were killed at different post-dosing times. Drug and/or metabolite concentrations in plasma, liver, kidney, heart, lung, and muscle tissues were analysed by HPLC procedures. Multi-exponential kinetic models were fitted to the observed tissue concentration-time data by applying a non-linear least-squares regression computer program. Tissue half-life, peak tissue concentration, and time of peak tissue concentration were determined. Half-life of CEF, SMM, SQ, OLA, PEN, ALB, and two metabolites of ALB (sulfoxide and sulfone) in various tissues ranged 0.6-1.4, 4.7-9.0, 4.5-18.9, 1.8-3.1, 0.9-3.0, 3.4-9.6, 5.0-16.1 and 7.4-12.2 h. The times required for CEF, SMM, SQ, OLA, PEN, and ALB residue concentrations to decline to 0.1 microgram/g in various tissues ranged from 5.0-11.6, 70.0-110.5, 114.0-179.8, 21.3-30.3, 4.1-24.8 and 47.8-84.4 h. Drug kinetic characteristics in tissues differed significantly from those in plasma, and also varied from tissue to tissue. It is necessary, therefore, to evaluate tissue kinetics when designing dosage regimens in tissue infection chemotherapy with these drugs. Knowledge of tissue kinetics is also important in predicting and controlling drug residues in edible tissues of food-producing animals.

Transfer of dietary sulphamonomethoxine and sulphadimethoxine into various tissues of laying hens

1. Sulphamonomethoxine (SMM) or sulphadimethoxine (SDM) were fed to laying hens at a dietary concentration of 400 mg/kg. Concentrations (mg/kg) of SMM and SDM in the blood, kidney, liver, ovary, muscle and adipose tissue, collected at 4, 8, 16 and 24 h after the start of feeding, were determined by HPLC. 2. The relationships between the sulphonamide concentrations (mg/kg) in the tissues and times (h) after the start of the feeding were analysed statistically. 3. Dietary SMM and SDM were transferred throughout the whole body, and concentrations in all tissues became constant 8 h after the start of feeding. 4. Among the 6 tissues examined the constant values (mg/kg) of both SMM and SDM were highest in the kidney and were lowest in adipose tissue. 5. With the exception of adipose tissue, the values of SDM in the tissues were statistically greater than those of SMM.

[Treatment of experimental glanders with combinations of sulfazine or sulfamonomethoxine with trimethoprim]

Combinations of sulfazine or sulfamonomethoxine with trimethoprim were found to be efficient in the prophylaxis and treatment of experimental glanders simulated by various strains and doses of the causative agent, the treatment being started and terminated at various periods. The efficacy indices and treatment schemes were elaborated. By the efficacy indices the sulfazine combination with trimethoprim was shown to be 2-3 times more efficient than the sulfamonomethoxine combination with trimethoprim.

Pharmacokinetic profile of sulphamonomethoxine-trimethoprim in horses after intravenous, intramuscular and oral administration

The pharmacokinetic profile of a sulphamonomethoxine-trimethoprim (SMM-TMP) combination was investigated in five horses. The combination was administered intravenously, intramuscularly and orally at a constant dose of 20 mg SMM plus 4 mg TMP kg-1 bodyweight. Following intravenous administration both drugs dispersed rapidly with distribution half-lives of about 12 minutes for SMM and about 18 minutes for TMP. Elimination half-lives for intravenous, intramuscular and oral administration were closely similar, indicating that elimination was independent of administration route. Bioavailability of the drugs in aqueous solution was good: about 72 per cent and 84 per cent for SMM and about 84 per cent and 98 per cent for TMP following intramuscular and oral administration, respectively. It is concluded that SMM-TMP administered orally once a day at 20 mg and 4 mg kg-1 bodyweight, respectively, maintains therapeutic concentrations, whereas twice daily intramuscular administration would be more effective for treating systemic infections in the horse than the once a day regimen usually adopted in veterinary practice.

Blood kinetics of sulfamonomethoxine and oxytetracycline following intrauterine spray injection in dairy cows

Intrauterine administration was performed in six Friesan cows with a disposable spray preparation containing 3 g of sulfamonomethoxine and 3 g of oxytetracycline, in order to investigate their serum kinetics. Sulfamonomethoxine levels were determined by a reversed-phase HPLC method, whilst oxytetracycline quantities were detected by a microbiological method. The sulphonamide had a peak 1.17 h after the administration, the tetracycline reached its highest concentration after 8 h. The bioavailability of both drugs was low and detectable drug amounts were no longer recovered after 24 h.

[A new drug sulfaton in the combined treatment of infections with sulfanilamide derivatives and diaminopyrimidine]

Derivatives of diaminopyrimidine as potentiators of the effect of the derivatives of sulfanilamide and other antibacterial drugs are discussed. Experimental data on sulfation, a new combined preparation, based on sulfamonomethoxine (a sulfanilamide derivative) and trimethoprim (a diaminopyrimidine derivative) are presented. Brief clinical characteristics of sulfation, its administration routes, doses, dosage advantages and better tolerance as compared to co-trimethoxazole+ (biseptol) are described.

An appropriate ingestion volume of oral sulfa drug suspension in pigs

The influence of ingested volume of a sulfa drug suspension, sodium sulfamonomethoxine (SMMNa), on the oral pharmacokinetics was studied in pigs, with regard to bioavailability and gastric emptying. Eighteen pigs, weighing 30-70 kg, were used. Phenol red solution was used for the evaluation of gastric emptying study. SMMNa suspension was used for pharmacokinetic study. Both of these fluids were administered by natural swallowing. Three experimental groups were constructed: G-I; 5 ml/kg of the test fluids to starved animals, G-II; 5 ml/kg of the test fluids to fed animals and G-III; 20 ml/kg of the fluids to fed animals. The glucose glycine electrolyte solution (GGES) was used as the vehicle for both the compounds. Six pigs, having duodenal cannula, were used for the study of gastric emptying. The gastric emptying rate was rapid in G-I, relatively rapid in G-III, and slow and variable in G-II. In agreement with the result of gastric emptying study, the values of Cmax and tmax were high and rapid in G-I, relatively high and rapid in G-III, and low and slow in G-II. Accordingly, the voluminous ingestion of drug suspension can facilitate the gastric emptying, in turn may make the oral absorption of the drug rapid-and-uniform. The 20 ml/kg volume of sulfa drug suspension may practically be recommended for the oral administration in pigs.

Role of deacetylation in the nonlinear pharmacokinetics of sulfamonomethoxine in pigs

The role of deacetylation in the pharmacokinetics of sulfamonomethoxine (SMM) in pigs was studied using 6 Goettingen minipigs and a pig from a commercial breed. The rapid decrease of plasma concentration of the parent compound followed by the rapid increase of plasma concentration of the deacetylated metabolite, SMM, was observed after an i.v. injection of N4-acetylsulfamonomethoxine (AcSMM; 10 mg/kg). The concentration of the metabolite, SMM, was greater than that of AcSMM and after reaching peak, both compounds decreased in parallel on a semilogarithmic graph. On the other hand, the acetylated compound of SMM (AcSMM) appeared in the plasma and reached peak after an i.v. injection of SMM. After reaching the peak, both SMM and AcSMM decreased in parallel. The slopes of the terminal phases of SMM and AcSMM after both injections showed no significant difference. After the i.v. injection of a high dose of SMM (100 mg/kg), a nonlinear pharmacokinetics profile with capacity limited elimination type of SMM was observed. The concentration of plasma AcSMM increased rapidly and the parallel decrease of SMM and AcSMM was observed in both nonlinear and linear phases, while the renal excretion of AcSMM was saturated in the nonlinear phase. The results suggest that the deacetylation in pigs is so strong that it largely affected the pharmacokinetics of SMM in both high and low doses. In spite of the saturation in renal excretion of the main metabolite, AcSMM, after the high dose, the profile of the parallel decrease remained unchanged, which may be due to the rapid conversion of the excess AcSMM to SMM. The converted SMM was added to the existing plasma SMM. As a result, the nonlinear pharmacokinetics of SMM may have occurred after a high dose of SMM in pigs.

A combination of sulfamonomethoxine and pyrimethamine versus other drugs for the treatment of malaria

Sixty-eight cases of vivax and 30 cases of falciparum malaria patients were treated with a combination of sulfamonomethoxine-pyrimethamine (MP tablet with 500 mg of sulfamonomethoxine and 25 mg of pyrimethamine) and the results were compared with those with chloroquine, Fansidar and quinine. Vivax malaria: Fever and parasites were cleared by the 4th day of treatment in 94 and 92% of the patients, respectively. Chloroquine was the most effective drug and Fansidar and MP tablets shared the next position. Falciparum malaria: Fever and asexual parasites were cleared by the 4th day of treatment in 67 and 78% of the patients, respectively. MP tablets were effective in chloroquine-resistant falciparum malaria contracted in Kalimantan (Indonesia) and Oceanian countries (Vanuatu etc.). Fever and parasite clearance times were shorter with chloroquine or with Fansidar than with MP tablets. Defective preschizonts used to appear following administration of MP tablets both in vivax and falciparum malarias. They were the premonitory laboratory indications that the asexual parasites will be soon eradicated.

Pharmacokinetic analysis of plasma concentration and urinary excretion of sulphamonomethoxine and its metabolite in Goettingen minipigs

The plasma concentration and renal excretion after a bolus intravenous injection of a low (10 mg/kg) or high (100 mg/kg) dose of sulphamonomethoxine (SMM) were studied in five Goettingen minipigs. The time data of plasma concentration after a low dose decreased rapidly and appeared to be linear on semilog graph paper. On the other hand, a decrease in the plasma concentration after a high dose was slow at first, gradually accelerated, then became rapid, showing that SMM disposition after a high dose (100 mg/kg) seemed to be non-linear with capacity-limited elimination. A large amount of the acetyl derivative of SMM (AcSMM), which was determined to be the main excretory product of SMM in urine, was detected in the plasma after SMM injection. As the ratios of the area under plasma concentration-time curve of AcSMM to that of SMM were not significantly different at either dose, the acetylation of SMM may be unsaturable by injection of 100 mg/kg of SMM. Immediately after the injection of a low dose, a rapid hyperbolic increase of the fraction of the cumulative amount of the excretory products in urine was observed. On the other hand, the fraction curve at the high dose rose slowly at first, then rapidly and hyperbolically. These results suggested that the non-linear drug disposition after a high dose (100 mg/kg) of SMM in pigs may be the result of a limited capacity for renal excretion of SMM and excretory products, especially the acetyl derivative.

[Several indices of the functional state of the adrenals of white rats during a prescribed course of sulfadimezine and sulfamonomethoxine combined with UV-irradiation]

Chronic treatment with sulfadimesin or sulfamonomethoxin combined with UV irradiation leads to potentiation of adrenocortical function. As the observation period increases, the weight ratios of the adrenals grow which is accompanied by the decreased content of ascorbic acid in them and by the reduced weight ratios of the goiter and spleen. Combined chronic use of sulfanilamides and UV irradiation results in an increase of the total acetylating capacity of the body, especially in the day time.

Chemotherapy of falciparum malaria: regional differences in responsiveness to treatment

A review of chloroquine and sulfa-antifol combination treated falciparum malaria patients revealed a high incidence of chloroquine-resistance, wither R1 or R2, in patients infected in Southeast Asia or Oceania. In addition, more than one tenth of the patients infected in Laos or Thailand were resistant to sulfa-antifol combinations. Chloroquine-resistant cases were sensitive to sulfa-antifol combinations. On the other hand, while all patients treated in Tokyo who had been infected in Africa or Sri Lanka were sensitive to chloroquine, a field study suggested the presence of chloroquine-resistant P. falciparum in the area near Kaduna, Nigeria. One patient infected in Nigeria showed partial resistance to the MP (sulfamonomethoxine-pyrimethamine) combination, and another patient infected in the Central African Empire showed resistance to the MP combination, increasing from R1 to R3 within a short period. The incidence of resistance to sulfa-antifol combination therapy was high in the West African tropical region. The continent, county and area of infection should be taken in consideration when selecting antimalarial drug(s) for the treatment and suppression of falciparum malaria.

[Human pharmacokinetic characteristics of sulfamonomethoxine depending on the drug form]

Comparative study of sulfamonomethoxin pharmacokinetics in the man given the drug per os or parenterally in the form of methylglucaminate showed that the latter favours higher blood concentrations of the drug 12 hours following injection. Sulfamonomethoxinmeglumin is absorbed more rapidly and has a greater bioavailability. The drug is mainly excreted with urine, more than a half being excreted in an acetylated form. It is recommended that the initial and maintenance doses be not less than 1000 and 500 mg for both dosage forms respectively. The interval between sulfanilamide administrations should not exceed 24 hours.

[Sulfadimezine and sulfamomomethoxine distribution in the body of white rats in single and repeated administration in combination with UV irradiation]

Experiments on white rats showed that single administration of sulfadimesin or sulfamonomethoxin combined with UV irradiation delays absorption, increases acetylation rate and diminishes excretion of the drugs with urine. During prolonged investigations it was established that repeated combined administration of sulfadimesin and UV irradiation produces a drop in the drug level in the blood and organs, increases acetylation rate and total acetylation activity in the body. Repeated combined administration of sulfamonomethoxin and UV irradiation produces a wave-like changes in the dynamics of the drug accumulation in the body and organs. Acetylation rate and total acetylation activity of the body rise as was shown in the course of prolonged investigations.

[Pharmacokinetics of sulfamonomethoxine and ite N-methylglucamine salt in rats]

Tests conducted with albino rats demonstrated that after intramuscular administration of N-methylglucaminic salt of sulphamonomethoxine there are built up higher concentrations of the compound in the blood and organs than with its enteral introduction. The maximal sulphamonomethoxine concentrations in rats with the compound administered by mouth are observed in 3-6 hours and with its intramuscular injection--over a space of 30 minutes-1 hour. Doubling the dose of injectable sulphamonomethoxine resulted in a higher content of the compound in the organism of rats by comparison with its administration by mouth.

Plasma concentrations, plasma protein binding and residues of sulfamonomethoxine in pigs, horses and cattle

The protein binding, the plasma half-life and the residue depletion of sulfamonomethoxine (SMM) after intramuscular administration were investigated in pigs, horses and cattle. Protein binding was weakly concentration-dependent. The bound fraction in plasma in the therapeutic range amounted to approximately 45, 40 and 50% for pigs, horses and cattle respectively, and the plasma half-lives were approximately 5.1, 5.7 and 3.1 hours respectively. SMM levels were less than 1 mug/g in muscle tissue after 36, 20 and 12 hours in pigs, horses and cattle respectively. In the kidney SMM levels were not less than 1 mug/g until 48, 60 (extrapolated) and 36 (extrapolated) hours respectively. In pigs and horses SMM residues in the injection site were extremely variable. In cattle, SMM disappearance from the injection site was more regular. SMM concentrations in pig, horse and cattle liver remained more or less constant in the latter part of the period investigated.