A systematic review of available clinical evidence - filgrastim compared with lenograstim.

BACKGROUND: Filgrastim (Neu-pogen®, Amgen) and lenograstim (Granocyte®, Chugai Pharma) are chemically different granulocyte colony-stimulating factors (G-CSFs). Based on receptor-binding studies and in vitro potency assessment, a clinical superiority of lenograstim versus filgrastim has been postulated together with potential cost savings favouring lenograstim over filgrastim. OBJECTIVES: To compare the clinical efficacy of filgrastim and lenograstim based on current Summaries of Product Characteristics (SPCs) for both products taking into account published clinical trials in patients and healthy volunteers. SEARCH STRATEGY AND SELECTION CRITERIA: PubMed and citation lists of published articles were used to identify clinical trials with direct comparisons of filgrastim and lenograstim. All available clinical information directly comparing filgrastim and lenograstim has been accepted for evaluation. DATA COLLECTION: A total of 16 studies compared filgrastim with lenograstim. Four studies had a randomized, parallel-group design, 4 had a cross-over design and 8 studies were uncontrolled. RESULTS: Available data do not suggest a clinically remarkable difference between filgrastim and lenograstim in chemotherapy-induced neutropenia and the mobilisation of peripheral blood progenitor cells (PBPC) in patients and healthy donors. CONCLUSIONS: Both G-CSFs are recommended for clinical use according to instructions in the respective SPCs; there is no reason to prefer lenograstim over filgrastim in any of the approved indications for both. Costs calculations need to consider the advent of biosimilar filgrastim in Europe.

Amoxicillin/clavulanic acid (875/125): bioequivalence of a novel Solutab tablet and rationale for a twice-daily dosing regimen.

A new amoxicillin/clavulanic acid tablet formulation (Solutab tablet, Forcid Solutab) containing amoxicillin/clavulanic acid (875/125) has been developed. The aim of the present study was to demonstrate bioequivalence between the new tablet formulation (test), taken as an intact tablet and after prior dispersal, versus the originator product viz. Augmentan film-coated tablet (875/125) used as reference. The study was performed in 48 healthy volunteers according to an open, single-dose, crossover design. Bioequivalence was demonstrated using Cmax and AUC(0-infinity) as primary parameters of evaluation for both amoxicillin and clavulanic acid with 90% confidence intervals of the ratios Solutab tablet/Augmentan within the range of 0.8-1.25. The duration of the plasma concentration exceeding the amoxicillin minimal inhibitory concentration (MICs) was calculated using individual plasma concentration-time curves and compartmental analysis. The data showed that the bioavailability characteristics of the test tablet, taken intact or in dispersed form, and the reference tablets were very similar. The analysis, moreover, also confirmed the appropriateness of using a b.i.d. dosage regimen for both formulations, taking into account the pharmacodynamic breakpoint values for some major pathogens.

Comparison of talinolol and atenolol effects on blood pressure in relation to lipid and glucose metabolic parameters. Results from the TALIP study.

AIMS: The primary objective of this double-blind, randomized, parallel-group study was to compare the influence ofthe selective beta1-receptor antagonists talinolol (100 mg) and atenolol (50 mg) on the lipid metabolism in hyperlipemic patients with mild to moderate hypertension after 12 weeks of treatment. As a secondary endpoint, the influence of the drug on blood pressure, pulse rate as well as glucose metabolism were examined. Furthermore, pharmacokinetic parameters were assessed. PATIENTS: Of the 198 patients recruited for the study, 166 were randomized to receive atenolol (n = 83) or talinolol (n = 83) for up to 12 weeks, 149 patients received the study medication for up to 48 weeks under double-blind conditions. RESULTS: There was no difference between the antihypertensive effect of both beta1-selective antagonists in patients with mild to moderate hypertension. No clinically relevant differences between the 2 drugs were observed for LDL cholesterol, HDL cholesterol, total cholesterol and triglycerides in the rather low doses given. However, there was evidence for a decrease in LDL cholesterol following treatment with talinolol, but not following treatment with atenolol, in patients with the highest initial blood pressure and in those with normalized blood pressure after 12 weeks of treatment. Parameters of glucose metabolism were not adversely affected by both drugs. Stable pharmacokinetics were observed over the 12-week administration, and steady state conditions were achieved after a 1-week treatment with both active compounds in the target population. Data indicate that once-a-day dosing can be performed with less fluctuation between peak and trough for talinolol in comparison to atenolol. Both treatments were well tolerated.

Bioequivalence study of a novel Solutab tablet formulation of amoxicillin/clavulanic acid versus the originator film-coated tablet.

With amoxicillin/clavulanic acid Solutab tablet, a new tablet formulation of amoxicillin/clavulanic acid (500/125), was developed. The aim of the present study was to demonstrate bioequivalence between the new tablet formulation, taken as an intact tablet and after prior dispersal, versus the originator product viz. Augmentan film-coated tablet. The study was performed in 48 healthy volunteers, according to an open, single-dose three-period, crossover design. Blood samples were taken prior to each administration and at 10 time points after dosing. Plasma concentrations of amoxicillin and clavulanic acid were determined by validated high performance liquid chromatography with UV detection. With regard to amoxicillin, the results were within the preset bioequivalence range of 0.8 to 1.25 for the ratios of the primary parameters AUC(0-t) and Cmax. In terms of clavulanic acid the 90% confidence intervals of the ratios for AUC(0-t) and Cmax versus the reference lay outside the predefined bioequivalence range of 0.75 to 1.33. This result, however, was mainly due to the large variability of the reference formulation compared to the amoxicillin/clavulanic acid Solutab tablet. Based on statistical indications that 3/48 subjects with extremely low levels on the reference formulation could be regarded as "outliers" and after excluding these subjects' data from the statistical analysis, results for clavulanic acid were within the predefined bioequivalence range of 0.75 to 1.33. Overall, the amoxicillin/clavulanic acid Solutab tablet provided, in comparison to the reference tablet, less variable levels of clavulanic acid, thus giving more appropriate protection to the available amoxicillin. Thirteen adverse events were reported post dosing by 7 subjects. There were no differences in incidence of adverse events between amoxicillin/clavulanic acid Solutab tablet taken intact or dispersed and Augmentan.

KA 672-HCl, a neuronal activator against dementia: tolerability, safety, and preliminary pharmacokinetics after single and multiple oral doses in healthy male and female volunteers.

In vitro and animal experiments have characterized KA 672-HCl as a potent functional antagonist of excitatory amino acid-induced convulsions and mortality. In receptor-binding studies, the compound displayed high affinities to several serotoninergic, adrenergic, and dopaminergic receptors and to the sigma receptor. The potential for short- and long-term toxicity of KA 672-HCl in rats and dogs was found to be low. Double-blind, randomized, placebo-controlled studies were undertaken in healthy volunteers ranging from 52 to 74 years of age to determine tolerability, safety, and preliminary pharmacokinetics of single and repeated doses in humans. Single doses up to 40 mg were well tolerated, with no difference in effect from placebo. At 60 mg, approximately half of the volunteers experienced a moderate drug-related orthostatic syndrome. After repeated doses of 10 or 20 mg KA 672-HCl for 14 days only minor adverse events of mild intensity were reported with no clear relation to dose or a clinically relevant difference from placebo. A mild decrease in semisupine and standing blood pressure 4 hours after administration was observed in the 20 mg group with no occurrence of orthostasis. Linear pharmacokinetics were observed after repeated doses. However, this was not the case after single-dose administration, as generally higher plasma concentrations were observed after the 20-mg dose than would have been predicted from the 10-mg data. The mean terminal phase half-life after the 20 mg dose was 11.1 hours and 13.7 hours after repeated and single doses, respectively. The safety and tolerability data support a continuation of therapeutic trials. KA 672-HCl is currently entering phase II development.

Pharmacokinetic profile of cefaclor.

Cefaclor is a well-absorbed oral cephalosporin antibiotic. Peak concentrations in serum are attained within 30-60 minutes. Food intake reduces the rate, but not the extent of absorption. Cefaclor is not metabolized to a significant degree, but it degrades chemically in the body with an approximate half-life of 2 hours. Most of the drug is excreted unchanged in the urine, the serum half-life after oral administration is 0.5-0.7 hours. Due to the chemical degradation, cefaclor does not accumulate to the same degree as other cephalosporins in case of renal impairment.

Pharmacokinetic and pharmacodynamic evaluation of triamcinolone acetonide after intravenous, oral, and inhaled administration.

Triamcinolone acetonide (TCA) is a corticosteroid that is frequently used in the treatment of asthma. After inhalation, TCA can become systemically available when the inhaled formulation is swallowed, causing undesirable systemic effects. A clinical study was conducted to determine the systemic side effects of TCA after intravenous (2 mg as phosphate ester), oral (5 mg), and inhaled (2 mg) administration. Blood samples were collected at appropriate times over 24 hours, and TCA concentrations in plasma were measured by high-performance liquid chromatography and radioimmunoassay. Free drug concentrations were determined by ultrafiltration for correlating pharmacokinetics and pharmacodynamics. The free fraction of TCA (+/- standard deviation) was 29.0 +/- 1.3% and was independent of the investigated concentration range up to 1,000 ng/mL. Pharmacodynamic parameters were determined by monitoring lymphocytes, granulocytes, and cortisol. Pharmacokinetic/pharmacodynamic modeling was performed using a modified Emax model for lymphocytes and granulocytes. A novel linear release rate model was used to characterize the cortisol data. The E50 values determined from all three pharmacodynamic endpoints were not significantly different for the three treatments, indicating that these effects can be explained based on systemic steroid concentrations.

Pharmacokinetics of triamcinolone acetonide after intravenous, oral, and inhaled administration.

The pharmacokinetics of triamcinolone acetonide were studied after intravenous (2 mg), oral (5 mg), and inhaled (2 mg) administration. Triamcinolone acetonide concentrations were measured in plasma by high-performance liquid chromatography/radioimmunoassay. After intravenous administration, triamcinolone acetonide was eliminated with a total body clearance of 37 L/h and a half-life of 2.0 hours. The volume of distribution was 103 L, and oral bioavailability averaged 23%. Absorption was rapid, achieving maximum triamcinolone acetonide levels of 10.5 ng/mL after 1 hour. After inhalation, bioavailability averaged 22% with maximum levels of 2.0 ng/mL observed after 2.1 hours. The resulting systemic levels for all three treatments caused a significant decrease in the number of lymphocytes in blood.

Influence of the xanthine derivative denbufylline and the anti-inflammatory agent nabumetone on microsomal free radical production and lipid peroxidation in rat liver.

The influence of denbufylline, nabumetone and its main metabolite BRL 10,720 on iron stimulated lipid peroxidation (LPO), cytochrome P 450 dependent H2O2 and chemiluminescence (CL) production was investigated in rat liver microsomes in vitro (10(-5)-10(-3) M) and in vivo after treatment of rats (5-300 mg/kg b.m. orally on three consecutive days). In rat liver slices the release of thiobarbituric acid reactants (TBAR) was measured after 1 hour of incubation with the drugs. Denbufylline, nabumetone and BRL 10,720 exerted a significant inhibition of iron stimulated LPO in vitro. Nabumetone showed the strongest antioxidative activity, which was also seen in liver slices. These antioxidative effects were not found after in vivo treatment of rats. Denbufylline (10(-3) M) additionally inhibited H2O2 formation and the luminol and lucigenin amplified CL in vitro. Unexpectedly, nabumetone increased H2O2 formation both in vitro and in vivo, but in vitro only lucigenin amplified CL. BRL 10,720 increased microsomal H2O2 production in vivo. Moreover, BRL 10,720 enhanced CL in vitro and in vivo significantly, which is interpreted as an increase of the production of superoxide anion radicals and other reactive oxygen species such as H2O2, but lipid peroxidation in liver microsomes was not enhanced. These results suggest that denbufylline, nabumetone and BRL 10,720 in contrast to the in vitro effects did not exert antioxidative activities after treatment of rats. On the contrary, BRL 10,720 was found to support the formation of reactive oxygen species in liver microsomes.

Influence of 3,5-dimethyl-3'-isopropyl-L-thyronine on thyroid state and gestational outcome in the Wistar rat.

3,5-Dimethyl-3'-isopropyl-L-thyronine (DIMIT, CAS 26384-44-1), a non-halogenated, artificial analogue of the thyroid hormone T3, was administered once daily by intragastric gavage to pregnant Wistar rats on days 17-20 of gestation to elucidate the effects of DIMIT on maternal and foetal thyroid state and gestational outcome under the influence of low iodine or iodine excess nutrition. Doses of 20 micrograms.kg-1.d-1 and 150 micrograms.kg-1.d-1 DIMIT were applied. Throughout pregnancy the animals were kept on low iodine diet and either on iodine free drinking water or iodine excess. There was no statistically significant effect on maternal body weight, weight of living foetus, the rate of intra-uterine death before day 16 of gestation, water and food consumption, and no hint of maternal thyrotoxicosis. The vital off-spring did not reveal any signs of gross malformation. DIMIT decreased serum TSH both in dams and foetus, and diminished the TSH stock of the pituitary gland of the dams. T3-levels were also lowered in maternal serum by DIMIT. These DIMIT induced effects were observed irrespective of iodine deficiency or excess. There was no difference in foetal mortality before onset of DIMIT-treatment, but the gestational death rate increased in a dose-related manner by the administration of DIMIT. This serious adverse effect became apparent at a DIMIT-dose that is not sufficient for a complete compensation of foetal hypothyroidism in utero. The higher prenatal mortality was accompanied by a decreased placental weight, but not by a reduced body weight of surviving foetus.

Ultrastructure of fetal pars-tuberalis-specific secretory cells under the influence of propylthiouracil and thyroxine.

The rat pituitary pars tuberalis (pt) is a functional and morphological unique component of the adenohypophysis. It mainly consists of specific secretory cells whose morphological and functional characterization is far from being complete. In this study the ultrastructure of fetal secretory pt cells developing under hypo- and hyperthyroid conditions was examined. Besides controls, young mature pregnant Wistar rats were treated with propylthiouracil (PTU) or thyroxine (T4). Areas of pt cells and of their nuclei were measured. Different cell organelles per cell were counted, and area densities of these organelles were determined. While the number of dictyosomes per cell area did not change, the area densities of long ribbons increased significantly in the experimental groups. Lysosomes and secretory granules, however, were found to be significantly diminished in pt cells of T4- and PTU-treated animals. The latter finding corresponds to earlier investigations when changes of the thyroid-stimulating-hormone-like immunoreactivity of fetal pt-specific cells were observed under the same experimental conditions. Results indicate that fetal pt-specific cells respond to changes of thyroid status in a manner different from pars distalis thyrotrophs. An interaction of pt-specific cells in thyroid regulation mechanisms is assumed.

Changes in TSH-immunoreactivity in the pars tuberalis and pars distalis of the fetal rat hypophysis following maternal administration of propylthiouracil and thyroxine.

The pars tuberalis (pt) of the adenohypophysis is unique in its close spatial relationship to the neurohemal contact area of the median eminence. The morphology of pt-specific secretory cells does not resemble cell types of the pars distalis (pd); the functional role of these cells within the endocrine system is still unknown. One group of young mature female Wistar rats received propylthiouracil (PTU), a second group thyroxine (T4) (10 mg/l each in drinking water) from about 3 weeks prior to the expected pregnancy and throughout the experiment. On gestation day 20, the fetuses were obtained by laparatomy. Serial sections from the rostral portion of the pt and from the pd were immunostained using the peroxidase-antiperoxidase method. TSH concentrations were determined by RIA in serum and pituitaries; T4 was measured in serum. An antiserum against rat (r) TSH revealed a moderate positive reaction of nearly all cells of the pt in the control group. In both experimental groups the pt-specific cells showed weak or no immunoreactivity. Sections of all groups were negative with anti(r)-LH, -GH, -PRL. In contrast to controls, only a few immature TSH-cells could be found in sections of the pd in the T4-group, while concentrations of TSH in blood and hypophysis were very low. TSH-cells in the PTU-group were enlarged and less intensely stained. TSH-concentrations were decreased in the hypophysis, blood levels were elevated. All sections of the pd-specific cell populations showed positive immunoreactions with anti-r)-LH, -GH, -PRL.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition by certain plant extracts of the binding and adenylate cyclase stimulatory effect of bovine thyrotropin in human thyroid membranes.

The present studies were undertaken to explore the mechanism by which, as previous studies have shown, freeze-dried aqueous extracts (FDE) of plants of the species Lycopus virginicus and Lycopus europaeus, Melissa officinalis (Laminaceae), and Lithospermum officinale (Boraginaceae) have the ability to inhibit at least many of the effects of exogenous and endogenous TSH on the thyroid gland. To this end, we have examined the in vitro effects of FDE from these plants on the ability of bovine TSH (bTSH) to both bind to human thyroid plasma membranes (TPM) and activate adenylate cyclase therein. FDE of these four species produced a dose-related, ultimately complete, inhibition of the binding of 125I-labeled bTSH when studied at 4 C in a 20 mM Tris-HCl-0.5% BSA buffer, pH 7.45. Half-maximum inhibition of bTSH binding was produced by approximately 50 mU/ml bTSH and only about 10-30 micrograms/ml of the four active FDE. When studied in Tris-BSA-50 mM NaCl buffer at 37 C, these FDE remained inhibitory to bTSH binding, but their potency was decreased to about one fifth of that seen in the absence of NaCl. The binding of [125I]hCG to rat testis membranes was also inhibited by all of these FDE, but no effect on the binding of [125I]insulin to crude rat liver membranes was observed. In concentrations as high as 1 mg/ml, FDE of Verbena officinalis (Verbenaceae), which belongs to the same order (Tubiflorae) as the other plants, but exhibits no antithyrotropic or antigonadotropic activity in vivo, had no effect on either the binding of bTSH to thyroid membranes or the binding of hCG to rat testis membranes. No inhibition of [125I]bTSH binding occurred when TPM were preincubated with the four active FDE, washed, and then incubated with [125I]bTSH in medium devoid of FDE. Hence, the inhibition of [125I]bTSH binding seen when labeled hormone and active FDE were added together was not due to irreversible binding of FDE to TPM or damage to the TSH receptor. When [125I]bTSH was incubated with the active FDE in Tris-BSA and the mixture was chromatographed on Sephadex G-100 using the same buffer, [125I]bTSH was shifted from an apparent mol wt of 30,000 and eluted at the void volume. Direct binding of [125I]bTSH in fractions from the new, large molecular peak was nil. Addition of a large excess of unlabeled bTSH during preincubation prevented the shift in the elution pattern of [125I] bTSH produced by these FDE.(ABSTRACT TRUNCATED AT 400 WORDS)

Antihormonal effects of plant extracts. Pharmacodynamic effects of lithospermum officinale on the thyroid gland of rats; comparison with the effects of iodide.

The antithyrotropic activity of freeze-dried-extracts from Lithospermum officinale (Lith. off. FDE) was investigated in the rat. When administered together with TSH, Lith. off. FDE blocked the TSH-induced increase in endocytotic activity of the thyroid glands followed by a strong decline of thyroid hormone levels. Furthermore, when Lith. off. FDE was injected alone it caused a decline in endogenous TSH-levels as well as in thyroidal secretion and thyroid hormone levels. The efficacy of the extract in blocking thyroid secretion was compared to that of potassium iodide and it was found that the effect of Lith. off. FDE was of more rapid onset and of longer duration, suggesting that the FDE may have a different mode of action from that of KJ. A specific interaction between TSH and the active constituents of the plant extract is discussed. Experiments on thyroidectomized and T4 substituted rats have demonstrated as an additional pharmacodynamic effect of Lith. off. FDE an inhibition of peripheral T4-deiodination.

T4 levels in methylxanthine-treated premature newborns.

The respiratory stimulants caffeine and theophylline are able to control apneic spells in premature newborns. However both substances have goitrogenic properties in rats on low-iodine diet. They lower T4 serum levels and inhibit TSH- and GH-release probably by enhancing hypothalamic somatostatin secretion. The retrospective study described here was carried out in an attempt to clarify whether treatment of premature children with methylxanthines has adverse effects on thyroid function. The results are as follows: 1) There is no significant correlation between caffeine- and theophylline-concentrations and circulating T4 levels in single blood specimen of unselected premature infants. 2) In none of the infants was a low T4-serum value accompanied by a rise in serum TSH during methylxanthine treatment. Thus methylxanthines are not associated with the induction of primary hypothyroidism but the possibility of tertiary hypothyroidism cannot be excluded. In order to avoid adverse effects on thyroid function the lowest therapeutically active dose should be chosen.

Formation of compounds with antigonadotropic activity from inactive phenolic precursors.

The antigonadotropic activity of Lithospermum and Lycopus species can be attributed to their phenolic components. These compounds represent precursors of biologically active products which are formed by an oxidation step. Complexity and instability of these products aggravates the elucidation of detailed structural properties. Therefore, the type of reaction involved had to be clarified. Among the oxidation products of phenolic substances, the corresponding quinones are found. It can be demonstrated that the reaction between quinones and unoxidized diphenols yields products with strong antigonadotropic activity. This type of reaction - the formation of quinhydrones - is proposed to be engaged in the formation of various products with antigonadotropic activity.

The relative merits of polyethyleneglycol as a separating agent in the radioimmunoassay of thyroid hormones.

Polyethyleneglycol (PEG) has been recommended as a separating agent in the assay of some peptide hormones (Desbuquois, B. and Aurbach, G.D. (1971) J. Clin. Endocrinol. 33, 732) and several substances of low molecular weight (Ratcliffe, J.G. (1974) Br. Med. Bull. 30, 32). In the present study the PEG-separation technique has been modified and adapted for the assay of thyroid hormones. Separation with PEG has the advantage of being cheap, rapid and relatively non-susceptible to disturbances as compared with the charcoal and double-antibody-solid phase techniques. The influence of different buffer systems, varying pH and ionic strength, on the precipitation process with PEG also has been investigated. Of the different systems tested barbital buffer containing 0.1% human serum albumin proved to be the best, preferably in the presence of bovine gamma-globulin. In the radioimmunoassay of T3 variations in pH and ionic strength are of minor importance whereas in the radioimmunoassay of T4 the adherence to a certain pH is recommended. Barbital buffer containing 0.1% bovine serum albumin was inadequate in the T3 radioimmunoassay, while Tris and phosphate buffers did not give satisfying results for either radioimmunoassay.