Anti-rheumatic drugs: present deadlock and new vistas

Indirect resolution of enantiomers of penicillamine by TLC and HPLC using Marfey's reagent and its variants

TLC and HPLC methods were developed for indirect chiral separation of penicillamine (3,3-dimethylcysteine) enantiomers after derivatization with Marfey's reagent (FDNP-Ala-NH(2)) and two of its structural variants, FDNP-Phe-NH(2) and FDNP-Val-NH(2). The binary mobile phase of phenol-water (3:1 v/v) and solvent combinations of acetonitrile and triethylamine phosphate buffer were found to give the best separation in normal and reversed-phase TLC, respectively. The diastereomers were also resolved on a reversed-phase C18 HPLC column with gradient elution of acetonitrile and 0.01 m trifluoroacetic acid. The results due to these three reagents were compared. The method was successful for checking the enantiomeric impurity of l-penicillamine in d-penicillamine and to check the enantiomeric purity of pharmaceutical formulations of d-penicillamine. The method was validated for linearity, repeatability, limit of detection and limit of quantification.

Design of copper-based anti-inflammatory drugs

It has been shown that the inflammation associated with rheumatoid arthritis can be reduced using copper complexes. In order to improve the bioavailability of copper and hence efficacy of these complexes we have synthesized three different series of ligands, each having different characteristics. Thermodynamic results for copper(II) complexes for these polyamino, diaminodiamido and triaminodiamido ligands are presented. The polyamino ligands form the most stable complexes in vivo but tissue distribution studies in mice show that [Cu(3,6,9,12-tetraazatetradecanedioate)] is excreted rapidly, unchanged in the urine. The diamino ligand complexes are much less stable than their polyamino analogues and animal studies using [Cu(N,N'-bis[2-(dimethylamino)ethyl]-ethanediamide)H2] indicate that the complex dissociates in vivo and is excreted slowly via the liver. The triaminodiamido copper(II) complexes are approximately 2 log units more stable than their diamino analogues. Computer simulation calculations indicate that these complexes are also likely to dissociate in plasma. Measured partition coefficients, however, suggest the possibility of dermal absorption.

Effects of indole-3-acetic acid on croton oil- and arachidonic acid-induced mouse ear edema

The indole-3-acetic acid (IAA) is a plant growth hormone (auxin) being considered as a tryptophan metabolite in animals. The main purpose of this work was to verify IAA's topical anti-inflammatory action using croton oil- or arachidonic acid-induced mouse ear edema, in comparison to known anti-inflammatory agents. IAA antioxidant activity was also verified by measuring the inhibition of brain homogenate lipid peroxidation with the thiobarbituric acid reactive substances (TBARS) test. IAA inhibited the action of both croton oil-and arachidonic acid-induced edema in a dose-dependent manner (4.0 mumoles IAA inhibited 75.8% in croton oil and 82.5% in arachidonic acid induced ear edema). Both IAA (5.3 mM) and indomethacin (8.0 mM) inhibited TBARS formation. Data suggest that IAA exhibits antiinflammatory effect possibly by its anti-oxidant activity.

Auranofin. A preliminary review of its pharmacological properties and therapeutic use in rheumatoid arthritis

Auranofin is the first orally active gold compound for the treatment of rheumatoid arthritis. Like other chrysotherapeutic agents, its exact mechanism of action is unknown, but it probably acts via immunological mechanisms and alteration of lysosomal enzyme activity. Although long term clinical experience with auranofin is limited, its efficacy appears to approach that of sodium aurothiomalate. Further comparative studies with aurothioglucose, hydroxychloroquine and D-penicillamine are required before definitive statements can be made regarding the relative efficacy of auranofin and these agents. While patients have demonstrated clinical remission of rheumatoid arthritis in response to auranofin therapy, radiological studies have been inconclusive regarding its effect on the occurrence or progression of erosive lesions. Auranofin is relatively well tolerated in most patients, but diarrhoea, skin rash, and pruritus are sometimes troublesome, and thrombocytopenia and proteinuria are potentially serious side effects which may occur during therapy. Whereas mucocutaneous side effects are more frequent with injectable gold compounds, gastrointestinal reactions are the most common adverse effect seen with auranofin. The frequency of side effects has been similar with auranofin and sodium aurothiomalate, but they are generally less severe with auranofin. While some of the side effects are controlled by a reduction in dosage, temporary or permanent withdrawal of auranofin may be necessary. Auranofin is clearly a useful addition to the limited list of agents with disease-modifying potential presently available for the treatment of rheumatoid arthritis. It will doubtless generate much interest as its final place in therapy becomes better defined through additional well-designed studies and wider clinical experience.

Raised plasma thromboxane B2 levels in alcoholic liver disease

In experimental animals endotoxin administration causes increased levels of thromboxane B2 and prostaglandins. Liver cirrhosis is often complicated by endotoxemia. In sixteen patients with alcoholic liver cirrhosis, we measured plasma thromboxane B2 levels. In twelve patients we found on one or more occasions raised plasma thromboxane B2 levels. Raised plasma thromboxane B2 levels were associated with significantly higher serum levels of urea, alkaline phosphatase, gamma glutamyl transpeptidase and lower antiplasmin and antithrombin III levels. It is possible that some of the complications in patients with alcoholic liver cirrhosis are mediated by thromboxanes.

2,6-Di-tert-butyl-4-(2'-thenoyl)phenol(R-830): a novel nonsteroidal anti-inflammatory agent with antioxidant properties

R-830, a di-tert-butylphenol, has been shown to be anti-inflammatory in a number of animal models. These include conventional systems such as carrageenan-induced edema and adjuvant arthritis of the rat and ultraviolet-induced erythema in the guinea pig in which the acidic nonsteroidal anti-inflammatory drugs (e.g., indomethacin) are effective. The anti-inflammatory activity of R-830 has also been demonstrated in other models (e.g., graft vs. host reaction and reversed passive cutaneous Arthus reaction in the rat, contact sensitivity in the mouse) in which the acidic nonsteroidal drugs are not effective. In vitro, R-830 inhibits guinea pig lung lipoxygenase and bovine seminal vesicle cyclo-oxygenase. The antioxidant properties of R-830 were demonstrated in two in vitro systems. We speculate that the antioxidant activity of this molecule might be related to its unusual profile of pharmacological activity.