Chronic eczema. The search for treatment of severe forms

Objective: to study the clinical efficacy of re-PUVA therapy in patients with torpid forms of chronic true hand eczema. Materials and methods: the study involved 78 patients (47 women, 31 men) with severe and moderate forms of chronic true hand eczema. Clinical indices were used before and after treatment: HECSI, DLQI. The patients were randomly divided into 3 groups: 1 group (25 people) received standard therapy (antihistamines, external glucocorticosteroid drugs, emollients); 2 group (27 people) received the indicated standard therapy against the background of PUVA; Group 3 (26 people) -standard therapy on the background of re-PUVA (combination of PUVA with retinoids (isotretinoin)). The duration of therapy was about 3 months. Results: in group I, before treatment, the average value of the HECSI index was 76.0 ± 37.9, and after the treatment, 63.6 ± 30.2; in group II, before treatment, the average value of the HECSI index was 78.3 ± 34.2, and after treatment it decreased to 51.5 ± 24.0, in group III, respectively, before treatment, the average HECSI was 77.2 ± 35.3, and after course of therapy 28.7 ± 14.0. The duration of remission in the first group after a course of standard therapy was 2.52 ± 1.1 weeks, in the second group 15.7 ± 7.5 weeks, in the third group 61.7 ± 32.4 weeks. Conclusions: The re-PUVA method is most effective in the treatment of chronic eczema of the hands in comparison with the PUVA and standard therapy

N-Aryl-7-hydroxy-5-oxo-2,3-dihydro-1H,5H-pyrido-[3,2,1-ij]quinoline-6-carboxamides. The Synthesis and Effects on Urinary Output

Continuing a targeted search for new leading structures with diuretic action among tricyclic derivatives of hydroxyquinolines, which are of interest as potential inhibitors of aldosterone synthase, the synthesis of a series of the corresponding pyrido[3,2,1-ij]quinoline-6-carboxanilides was carried out by amidation of ethyl-7-hydroxy-5-oxo-2,3-dihydro-1H,5H-pyrido[3,2,1-ij]quinoline-6-carboxylate with aniline, aminophenols and O-alkylsubstituted analogs with high yields and purity. The optimal conditions of this reaction are proposed; they make it possible to prevent partial destruction of the original heterocyclic ester and thereby avoid formation of specific impurities of 7-hydroxy-2,3-dihydro-1H,5H-pyrido[3,2,1-ij]quinolin-5-one. To confirm the structure of all substances obtained, elemental analysis, nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry were used. Moreover, the peculiarities of their 1H and 13C-NMR spectra, as well as their mass spectrometric behavior under conditions of electron impact ionization, were discussed. The effect of pyrido[3,2,1-ij]quinoline-6-carboxanilides on the urinary function of the kidneys was studied in white rats of both genders by the standard method of oral administration at a dose of 10 mg/kg. Testing was conducted in comparison with hydrochlorothiazide, as well as with structurally close pyrrolo[3,2,1-ij] quinoline-5-carboxanilides studied earlier with the same substituents in the anilide fragments. It was found that addition of one methylene unit to the heterocycle partially hydrogenated and annelated with the quinolone core has a positive impact on biological properties—most of the substances studied exhibit a statistically significant diuretic effect exceeding the activity of not only hydrochlorothiazide, in some cases, but also the action of the structural analogs. The important structural and biological regularities, which are common with pyrroloquinolines and introduced by a chemical modification, were revealed. The importance of the presence in the structure of terminal amide fragments of tricyclic quinoline-3-carboxamides of a 4-methoxy-substituted aromatic ring was particularly marked. The expediency of further study of pyridoquinolines as promising diuretic agents has been shown

Methyl 4-Hydroxy-2,2-Dioxo-1H-2λ6,1-Benzothiazine-3-Carboxylate and Its Analogs Modified in the Benzene Moiety of the Molecule as New Analgesics

In order to identify new regularities of the “structure–analgesic activity” relationship in the series of 2,1-benzothiazine derivatives, the synthesis of methyl 4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate and a group of its analogs substituted in the benzene moiety of the molecule, as well as their mono-and diammonium salts, was performed with tris(hydroxymethyl)aminomethane. The algorithm was proposed; it allows for uniquely solving the question of the nature of the substituent and its true position in the benzothiazine core based on the complex use of NMR (1H and 13C) and mass spectrometry data. Using single-crystal X-ray diffraction analysis it was proven that salt formation first passes through the cyclic sulfamide group and only then through the 4-hydroxyl group, and is always accompanied by a significant conformational rearrangement of the molecule. Based on the results of pharmacological tests it was found that modification of the benzene moiety of the molecule can be used as a method for enhancing the analgesic properties of the class of compounds studied. The presence of a substitute in position 7 is particularly effective, regardless of its nature. A comparative analysis of the analgesic activity of the initial esters and their mono- and diammonium salts convincingly showed that the common belief about a direct relationship between the solubility of a substance and the level of its biological effect is not always true. As it turned out, increasing the solubility in water can lead to a variety of consequences: From a significant increase in analgesia to its complete elimination. It was suggested that the analgesic activity of the compounds studied is determined not by solubility, but by the molecular conformations formed during their obtainment

The Study of the Structure—Diuretic Activity Relationship in a Series of New N-(Arylalkyl)-6-hydroxy-2-methyl-4-oxo-2,4-dihydro-1H-pyrrolo-[3,2,1-ij]quinoline-5-carboxamides

In accordance with the principles of “me-too” technique, the preparative method for obtaining has been proposed, and the synthesis of a large series of new N-(arylalkyl)-6-hydroxy-2-methyl-4-oxo-2,4-dihydro-1H-pyrrolo[3,2,1-ij]quinoline-5-carboxamides as structurally close analogs of tricyclic pyrrolo- and pyridoquinoline diuretics has been carried out. All target compounds were obtained with high yields and purity by amidation of ethyl ester of the corresponding 2-methyl-pyrroloquinoline-5-carboxylic acid with arylalkylamines in boiling ethanol. Their structure was confirmed by the data of elemental analysis, nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry and polarimetry. Moreover, interpretations of their 1H and 13C-NMR spectra, their mass spectrometric behavior, as well as peculiarities of the polarimetric studies were discussed. The effect of N-(arylalkyl)-6-hydroxy-2-methyl-4-oxo-2,4-dihydro-1H-pyrrolo[3,2,1-ij]quinoline-5-carboxamides on the urinary function of the kidneys was studied in white rats by the standard method of oral administration in the dose of 10 mg/kg compared to hydrochlorothiazide. According to the results of the primary pharmacological screening, the structural and biological regularities that were unexpected, but interesting for further studies were revealed. Among the substances studied, the samples, which by their diuretic effect are not inferior and even superior to both the known hydrochlorothiazide and the lead structure of the pyrroloquinoline group, have been found. On this basis, it can be argued that the introduction of the methyl group made by us in position 2 of pyrrolo[3,2,1-ij]quinoline nucleus can be considered as a successful and promising implementation of the “me-too” cloning of tricyclic 4-hydroxyquinoline-2-one diuretics

Crystal Habits and Biological Properties of N-(4-Trifluoromethylphenyl)-4-Hydroxy-2,2-Dioxo-1H-2λ6,1-Benzothiazine-3-Carboxamide

In order to study polymorphic modifications of N-(4-trifluoromethylphenyl)-4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamide, which is of interest as a promising analgesic, its three colorless crystal forms with different habitus have been obtained: sticks of ethyl acetate, plates of meta-xylene and blocks of ortho-xylene. However, the X-ray diffraction analysis has shown that all the forms studied have the identical molecular and crystal structure in spite of such significant differences in appearance. Moreover, pharmacological tests have revealed significant differences in the analgesic activity in these samples (a total of five experimental models were used: “acetic-acid-induced writhing”, “hot plate”, “thermal irritation of the tail tip” (tail-flick), “tail electric stimulation” and “neuropathic pain”), acute toxicity and the ability to cause gastric damage. As a result, only the plate crystal form of N-(4-trifluoromethylphenyl)-4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamide is recommended for further studies. Thus, it has been proven that the habitus of crystals is an important characteristic of the drug substance and is able to have a noticeable effect on its biological properties. Changes in habitus should be considered as a guide to the mandatory verification of at least the basic pharmacological parameters of the new form regardless of whether the molecular and crystal structure changes

Synthesis, Crystal Structure, and Biological Activity of Ethyl 4-Methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate Polymorphic Forms

Continuing the search for new potential analgesics among the derivatives of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid, the possibility of obtaining its esters by the alkylation of the corresponding sodium salt with iodoethane in dimethyl sulfoxide (DMSO) at room temperature was studied. It was found that under such conditions, together with the oxygen atom of the carboxyl group, a heteroatom of nitrogen is also alkylated. Therefore, the product of the reaction studied is a mixture of ethyl 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate (major) and its 1-ethyl-substituted analog (minor). A simple but very effective method of preparative separation of these compounds was proposed. Moreover, the heterogeneous crystallization from ethanol was revealed to result in a monoclinic polymorphic form of ethyl 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate, while the homogeneous crystallization results in its orthorhombic form. The molecular and crystal structures of both forms were confirmed by X-ray diffraction analysis, and the phase purity by powder diffraction study. The pharmacological tests carried out on the model of a carrageenan edema showed that the screening dose of 20 mg/kg of 1-ethyl-substituted ester and the orthorhombic form of its analog unsubstituted in position 1 exhibited weak anti-inflammatory and moderate analgesic effects. At the same time, the monoclinic form of ethyl 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate appeared to be both a powerful analgesic and an anti-inflammatory agent that exceeded Piroxicam and Meloxicam in the same doses by these indicators. A detailed comparative analysis of the molecular and crystal structures of two polymorphic forms of ethyl 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate was carried out using quantum chemical calculations of the energies of pairwise interactions between molecules. An explanation of the essential differences of their biological properties based on this was offered

Synthesis and Regularities of the Structure–Activity Relationship in a Series of <i>N</i>-Pyridyl-4-methyl-2,2-dioxo-1<i>H</i>-2λ⁶,1-benzothiazine-3-carboxamides

According to our quantum and chemical calculations 4-methyl-2,2-dioxo-1H-2&#955;6,1-benzothiazine-3-carboxylic acid imidazolide is theoretically almost as reactive as its 2-carbonyl analog, and it forms the corresponding N-pyridyl-4-methyl-2,2-dioxo-1H-2&#955;6,1-benzothiazine-3-carboxamides with many aminopyridines. However, in practice, the sulfo group introduces significant changes at times and prevents the acylation of sterically hindered amines. One of these products was 2-amino-6-methylpyridine. Thus, it has been concluded that aminopyridines interact with imidazolide in aromatic form where the target for the initial electrophilic attack is the ring nitrogen. To confirm the structure of all substances synthesized, 1H-NMR spectroscopy and X-ray diffraction analysis were used. From X-ray diffraction data it follows that in the crystalline phase the carbonyl and sulfo group may occupy different positions with respect to the plane of the benzothiazine bicycle: this position may be unilateral, typical for 4-methyl-2,2-dioxo-1H-2&#955;6,1-benzothiazine-3-carboxamides, versatile, and not yet encountered in compounds of this type. A comparison of these data with the results of the pharmacological screening conducted on the standard model of carrageenan inflammation showed that the N-pyridylamides of the first group demonstrated a direct dependence of their analgesic and anti-inflammatory activity on the mutual arrangement of the planes of the benzothiazine and pyridine fragments. The new molecular conformation of the benzothiazine nucleus provides a sufficiently high level of analgesic (but not anti-inflammatory) properties in all N-pyridylamides of the second group with an extremely weak dependence on the spatial arrangement of the pyridine cycle. All substances presented this article proved themselves in varying degrees as analgesics and antiphlogistics. Moreover, two of them&#8212;N-(5-methylpyridin-2-yl)- and N-(pyridin-3-yl)-4-methyl-2,2-dioxo-1H-2&#955;6,1-benzothiazine-3-carboxamides&#8212;exceeded the most effective drug of oxicam type Lornoxicam by these indicators