Structural requirements for duodenal permeability of heparin-diamine complexes.

We have compared the physico-chemical behaviors alone and in the presence of a synthetic bilayer membrane, in aqueous solution and the bioavailability after intraduodenal administration to rabbits, of the two heparin diamine salts ITF-300 and ITF-331 with those of the heparin-amine salt ITF-1175. The three salts have similar structures but different characteristics of compounds tend to form aggregates in solution, but at different critical concentrations. The compounds induce fusion of single-walled vesicles of a synthetic peptide lipid into multi-walled lamellae. The minimal concentrations of the compounds required for the formation of such lamellae differ. This behavior in solution explains the differences in absorption in the animal model. This makes it possible to correlate enhanced heparin bioavailability with the structural nature of the diamine counter-ions used to prepare heparin salts.

Dietary iron deficiency in the rat. II. Recovery from energy metabolism derangement of the hepatic tissue by iron therapy.

Severe iron deficiency in rats was found to be associated with abnormal lipid accumulation in the liver and impairment of the oxidative metabolism in the hepatic tissue. Iron therapy, consisting in oral administration to iron-deficient 4-week-old rats of iron succinyl-albumin complex, at a daily dose of 10 mg/kg body weight, over a period of 7 days, almost completely corrected these functional anomalies. This treatment fully reverted severe anemia associated with iron deficiency. The level of iron in the hepatic tissue and in the mitochondrial fraction also increased largely. By contrast, no significant improvement in the lowered level of cytochromes occurred. Iron supplements significantly decreased the abnormal level of liver total lipids and serum triglycerides. Concomitantly, iron repletion fully reverted the partial loss of coupled function in isolated mitochondria and the energy state perturbation of the liver. A close relationship among abnormal lipid accumulation, impairment of mitochondrial oxidative phosphorylation and energy derangement in the hepatic cell in this experimental model of severe dietary iron deficiency anemia appears to be likely.

Anti-HIV type 1 properties of chemically modified heparins with diminished anticoagulant activity.

Several groups have reported that sulfated polysaccharides are potent and selective in vitro inhibitors of human immunodeficiency virus type 1 (HIV-1); however, their therapeutic application is limited by their anticoagulant activity. In view of possible improvements in therapeutic potential, a number of heparin derivatives with reduced anticoagulant activity were studied for their inhibitory activity of an HIV-dependent syncytium formation assay, in comparison with standard anionic polysaccharides, such as sodium heparin, dextran sulfate, and heparin sulfate. The chemical modifications introduced in the heparin molecule included succinylation of desulfated N groups (Suc-H), exhaustive periodate oxidation and reduction (RO-H), and controlled nitrous acid degradation (LMW-H). The most pronounced anti-HIV activity was observed with RO-H, Suc30-H (standard heparin, 30% succinylated), and Suc100-LMW-H (low molecular weight heparin, 100% succinylated); the latter retained only 5% of the anticoagulant activity of standard heparin, whereas RO-H and Suc30-H retained approximately 35% of the anticoagulant activity of standard heparin. A safety ratio (arbitrary units of anti-HIV activity per anticoagulant international unit) was calculated: by this parameter, RO-H, Suc30-H, and Suc100-LMW-H were, respectively, 48-, 3.6-, and 1644-fold more safe than standard heparin.

Comparison of anti-anaemic effects of iron protein succinylate (ITF 282) and ferrous sulfate in the rat.

The effects of iron protein succinylate (ITF 282), an iron complex insoluble under acid conditions, and ferrous sulfate were studied in the rat. After a single oral administration of ITF 282, the concentration of free iron in the stomach was less than the 10% of that found after a corresponding dose of ferrous sulfate and the effect of induction of diarrhoea was significantly less important than that of ferrous sulfate. Iron absorption and kinetics were evaluated by measuring serum iron after oral administration of equidoses of iron to the anaemic rat. The results showed that ferrous sulfate induces higher serum iron levels than ITF 282. The anti-anaemic effects of the two iron products were studied during 4 weeks of treatment (3 mg iron/kg/day): the data obtained confirmed that ferrous sulfate is significantly more potent in increasing serum iron, but in contrast both compounds are equally active in restoring normal haemoglobin values.

Chemical and biological characterization of iron-protein succinylate (ITF 282).

ITF 282 is an iron succinyl casein complex containing 5% iron. The main property of the derivative is to keep iron bonded at acidic pH values. This accounts for a better tolerability of the compound compared with iron salts, during the treatment of iron deficiency. Pharmacological studies in normal and anemic rats demonstrated that this iron complex is almost as active as ferrous sulphate against iron deficiency anemia, but it is significantly less potent in increasing serum iron. Better gastrointestinal tolerability of ITF 282 was demonstrated in rats and dogs. Chemical and pharmacological properties of iron-protein succinylate are described.

Heparin by alternative routes of administration.

In a study investigating the bioavailability of heparin administered by different routes, we also compared its bioavailability in the dog after oral administration of two enteric-coated formulations, one containing a heparin preparation (ITF-300) and the other sodium heparin. After administration of the formulation containing sodium heparin, there was no heparin in plasma, but when the formulation containing ITF-300 was given, plasma heparin levels were detectable.

Gastrointestinal effects of single and repeated doses of ferrous sulphate in rats.

The gastrointestinal effects of single and repeated administration of ferrous sulphate was evaluated measuring faecal flora modifications and histology of stomach and duodenum of the rat. The acute experiments showed reversible histopathological lesions of stomach and duodenum with iron deposition and increase in faecal Cl. perfringens toxin after treatment with a high dose of FeSO4. The chronic experiment at lower doses showed no relevant histological damage, some iron deposition and strong alterations in faecal flora. A strong impact of oral FeSO4 on gastrointestinal environment was demonstrated.

Desferrioxamine potentiated SOD antiinflammatory activity in rat adjuvant arthritis: role of iron and bacterial toxins.

In this paper we studied the modulating inflammatory activity of iron in the adjuvant arthritis, taking indomethacin as a standard antiinflammatory drug and a superoxide dismutase derivative (MPEG-SOD) as a scavenger of free radicals. Moreover, we evaluated the changes in potential intestinal pathogens requiring iron for growth, in order to study the role of bacteria in the altered gastrointestinal functions observed during arthritis. We observed a 50% arthritis inhibition on the 14th day with MPEG-SOD plus desferrioxamine, a significant decrease in serum iron in arthritic rats compared to controls, and a significant Cl. perfringens increase on the 28th day in the presence of MPEG-SOD. Our data demonstrate that hypoferremia, in arthritis, is a protective mechanism overall in the early phase and could protect the intestinal tract by inhibiting the development of potential pathogens.

Intraduodenal absorption in the rabbit of a novel heparin salt.

The intraduodenal absorption of a new low-molecular-weight heparin (LMWH) diamine salt (ITF 1331) was compared with the parent compound ITF 1060 and with sodium LMWH, in anaesthetized rabbits. The administration of either salt, but not of sodium LMWH, resulted in a dose-related increase in plasma anti-Xa activity. In this respect ITF 1331 was slightly superior to ITF 1060, and in acute-toxicity studies the counterion itself (ITF 258) was less toxic than that in ITF 1060 (counterion No. 4). These data confirm that a tertiary diamine within the counterion is an important structural requirement for the bioavailability of heparin by the intraduodenal route, and suggest that ITF 1331 may represent an important advance in the search for an oral heparin.