Study on hydrophilicity and degradability of chitosan/polylactide-co-polycaprolactone nanofibre blend electrospun membrane

Electrospinning is an interesting technique to produce polymer membranes made of entangled nanofibres. The technique is raising interest in pharmaceutical and biomedical areas. Either electrospun membranes are studied for tissue regeneration purposes, or incorporation of nanoparticles in electrospun membranes can be an opportunity to control the delivery of drug or to obtain dual drug delivery system. In this work suspensions of hydrochloride chitosan salt in copolymer polylactide-co-polycaprolactone (PLA-PCL) solution were electrospun in order to assess an advanced study for developing polymer nanofibre blend membrane loaded with chitosan polymer. The aim of the work was to investigate the properties and stability of chitosan/PLA-PCL electrospun membranes considering their application for tissue regeneration and drug delivery. The electrospun membranes were characterized for their physico-chemical (FT-IR) morphology (SEM) and in vitro biological properties (cytocompatibility and cells engraftment). Results show that homogeneous electrospun PLA-PCL/chitosan blend nanofibres in the range size 800 nm were obtained. Chitosan was loaded inside the nanofibres up to 27.2% (w/w) without modifying nanofibre shape, and only 6% of the loaded chitosan resulted to be on the nanofibre surface. The presence of chitosan in the nanofibres has shown to accelerate the electrospun membranes degradation in vitro.

Emerging and re-emerging infectious disease in otorhinolaryngology

SUMMARY

Emerging and re-emerging infectious disease in otorhinolaryngology (ENT) are an area of growing epidemiological and clinical interest. The aim of this section is to comprehensively report on the epidemiology of key infectious disease in otorhinolaryngology, reporting on their burden at the national and international level, expanding of the need of promoting and implementing preventive interventions, and the rationale of applying evidence-based, effective and cost- effective diagnostic, curative and preventive approaches. In particular, we focus on i) ENT viral infections (HIV, Epstein-Barr virus, Human Papilloma virus), retrieving the available evidence on their oncogenic potential; ii) typical and atypical mycobacteria infections; iii) non-specific granulomatous lymphadenopathy; iv) emerging paediatric ENT infectious diseases and the prevention of their complications; v) the growing burden of antimicrobial resistance in ENT and the strategies for its control in different clinical settings. We conclude by outlining knowledge gaps and action needed in ENT infectious diseases research and clinical practice and we make references to economic analysis in the field of ENT infectious diseases prevention and care.

Multivariate analysis for the optimization of microfluidics-assisted nanoprecipitation method intended for the loading of small hydrophilic drugs into PLGA nanoparticles

Design of Experiment-assisted evaluation of critical process (total flow rate, TFR, flow rate ratio, FRR) and formulation (polymer concentration and structure, drug:polymer ratio) variables in a novel microfluidics-based device, a staggered herringbone micromixer (SHM), for poly(lactic-co-glycolic acid) copolymer (PLGA) nanoparticles (NPs) manufacturing was performed in order to systematically evaluate and mathematically describe their effects on NPs sizes and drug encapsulation; a small hydrophilic moiety, N-acetylcysteine, was chosen as challenging model drug. SHM-assisted nanoprecipitation method consistently yielded NPs with tailor made sizes (in the range of 100-900 nm) and polydispersity index range from 0.061 to 0.286. Significant effects on NPs sizes were highlighted for TFR and FRR: increasing TFR (from 5 to 15 mL/min) and decreasing FRR (from 1:1 to 1:5 v/v, acetonitrile: buffer) NPs with mean diameter <200 nm were obtained. SHM technique allowed for flexible, application-specific tuning of PLGA NPs size using organic solvents with relatively low toxicity (acetone, acetonitrile), varying aqueous phase composition (Tris buffer vs PVA aqueous solution) and PLGA characteristics (Mw ranging from 25-90 kDa, capped or un-capped PLGA, different lactide:glycolide molar ratio). A very satisfactory N-Ac encapsulation efficiency (more than 67%) and a prolonged release (by 168 h) were achieved.

Long-term effect of gamma irradiation on the functional properties and cytocompatibility of multiblock co-polymer films

The purpose of this work was to investigate the long-term effect of gamma-irradiation treatment on the functional properties of PEG-PDLLA and PEG-PLGA films and to evaluate the cytocompatibility of sterilized samples. Chemical and thermal properties, and cytocompatibility of sterilized films were detected for samples at time zero and after storage at 5 ± 3°C for 60 days. An in vitro degradation study was carried out on polymer samples to examine the effect of sterilization on the degradation performances of co-polymer films. Incubated samples were characterized in terms of film surface structure (SEM), chemical (GPC) and thermal (DSC) properties. The study performed on films upon gamma sterilization showed no significant changes of the PEG-PDLLA and PEG-PLGA film structure, while GPC analysis highlighted that the effect of gamma irradiation was dependent on the Mw and composition of polymers. DSC traces suggested more pronounced gamma-ray effects on the PEG-PLGA multiblock co-polymer. During the stability study important changes in terms of structure surface, thermal properties and cytocompatibility were observed and investigated. Data collected during the in vitro degradation study emphasized the need to know and investigate the degradation performances and behaviour of polymer or polymer systems (as DDS, scaffolds and bandage) treated with gamma rays.

Induction of an in vitro reversible hypometabolism through chitosan-based nanoparticles

OBJECTIVE

Chitosan-based nanoparticles (NPs) were prepared to promote intracellular sustained delivery of the synthetic delta opioid D-Ala(2)-D-Leu(5)-enkephalin (DADLE), prolonging peptide activity and inducing a safe and reversible hypometabolic state.

MATERIALS AND METHODS

NPs were prepared by combining ionotropic gelation and ultrasonication treatment. NP uptake studies and the effects of encapsulated DADLE on HeLa cells proliferation were tested by transmission electron microscopy (TEM) analysis, by immuno-fluorescence and immuno-cytochemistry.

RESULTS

DADLE-loaded NPs are produced with suitable characteristics, a satisfactory process yield (55.4% ± 2.4%) and encapsulation efficiency (64.6% ± 2.1%). NPs are effective in inducing a hypometabolic stasis at a 10(-4) M DADLE concentration. Moreover, as seen from the immunofluorescence study, the effect persists through the recovery period (72 h). Indeed, NPs labelled by anti-enkephalin antibody inside cell nucleus reassert that the in vivo release of the peptide can be prolonged with respect to the case of free peptide supply.

CONCLUSION

The nanoparticulate drug delivery system described seems to be effective in inducing and prolonging a sort of hibernation-like state in the cells.

Biodegradable microspheres for prolidase delivery to human cultured fibroblasts

Prolidase deficiency (PD) is a rare autosomal recessive disorder caused by inadequate levels of the cytosolic exopeptidase prolidase (E.C. 3.4.13.9), for which there is not, as yet, a resolutive cure. We have investigated whether biodegradable microspheres loaded with prolidase could release active enzyme inside cells, to consider this system as a possible therapeutic approach for prolidase deficiency. Poly(lactide-co-glycolide) microspheres were prepared, modifying the classical double emulsion solvent evaporation method to mitigate the burst effect of the enzyme from the microspheres. Ex-vivo experiments were performed, by incubating microencapsulated prolidase with cultured fibroblasts from PD patients and from controls, to determine the amount of active enzyme delivered to the cells. The microparticulate drug delivery system described carried small amounts of active prolidase inside fibroblasts, ensuring a response to the intracellular accumulation of X-Pro dipeptides, the mechanism that is supposed to be responsible for the development of clinical manifestations of this disorder in man. A positive result of the presence of active enzyme inside cells was an improvement in fibroblast shape.

Polyethylenglycol-co-poly-D,L-lactide copolymer based microspheres: preparation, characterization and delivery of a model protein

PURPOSE

To prepare and characterize polyethylenglycol-co-poly-D,L-lactide (PEG-D,L-PLA) multiblock copolymer microspheres containing ovalbumin. Microsphere batches made of Poly-D,L-lactide (PLA) homopolymers were prepared in order to evaluate how the presence of PEG segments into PEG-D,L-PLA copolymer could affect the behaviour of microspheres as carrier of protein drugs.

METHODS

The PEG-D,L-PLA and PLA microspheres, loaded with the model protein ovalbumin, were prepared using double emulsion solvent evaporation method. The effect of PEG segments in the microparticles matrix, on the morphology, size distribution, encapsulation efficiency and release behaviour was studied.

RESULTS

According to the results, PEG-D,L-PLA microspheres were more hydrophilic than PLA microparticles and with lower glass transition temperature. The surface of PEG-D,L-PLA microspheres was not as smooth as that of PLA microparticles, the mean diameter of PEG-D,L-PLA microparticles was bigger than that of PLA microspheres. Protein release from the microspheres was affected by the morphological structure of PEG-D,L-PLA microspheres and properties of PEG-D,L-PLA copolymer. This study suggests that PEG-D,L-PLA multiblock copolymer may be used as carrier in protein delivery systems for different purposes.

gamma-irradiation of PEGd,lPLA and PEG-PLGA multiblock copolymers: II. effect of oxygen and EPR investigation

The purpose of this research was to evaluate how the presence of oxygen can affect irradiation-induced degradation reactions of PEGd,lPLA and PEG-PLGA multiblock copolymers submitted to gamma irradiation and to investigate the radiolytic behavior of the polymers. PEGd,lPLA, PEG-PLGA, PLA, and PLGA were irradiated by using a (60)Co irradiation source in air and under vacuum at 25 kGy total dose. Mw and Mn were evaluated by gel permeation chromatography. The stability study was carried out on three samples sets: (a) polymer samples irradiated and stored in air, (b) polymer samples irradiated and stored under vacuum, and (c) polymer samples irradiated under vacuum and stored in air. The thermal and radiolytic behavior was investigated by differential scanning calorimetry and electron paramagnetic resonance (EPR), respectively. Samples irradiated in air showed remarkable Mw and Mn reduction and Tg value reduction due to radiation-induced chain scission reactions. Higher stability was observed for samples irradiated and stored under vacuum. EPR spectra showed that the presence of PEG units in multiblock copolymer chains leads to: (a) decrease of the radiolytic yield of radicals and (b) decrease of the radical trapping efficiency and faster radical decay rates. It can be concluded that the presence of oxygen during the irradiation process and the storage phase significantly increases the entity of irradiation-induced damage.

gamma-Irradiation of PEGd,lPLA and PEG-PLGA multiblock copolymers. I. Effect of irradiation doses

To evaluate the effects of different gamma irradiation doses on PEGd,lPLA and PEG-PLGA multiblock copolymers. The behaviour of the multiblock copolymers to irradiation was compared to that of PLA, PLGA polymers. PEGd,lPLA, PEG-PLGA, PLA and PLGA polymers were irradiated by using a (60)Co irradiation source at 5, 15, 25 and 50 kGy total dose. Characterization was performed on all samples before and after irradiation, by nuclear magnetic resonance (NMR), infrared absorption spectrophotometry (FTIR) and gel permeation chromatography (GPC). The effect of gamma irradiation on polymer stability was also evaluated. Results of NMR and FTIR suggest an increase in -OH and -COOH groups, attributed to scission reactions induced by irradiation treatment. Data of GPC analysis showed that the weight average molecular weight (Mw) of polymer samples decreased with increasing irradiation dose. The extent of Mw degradation expressed as percentage of Mw reduction was more prominent for polymers with high molecular weight as PEGd,lPLA and PLA. The dominant effect of gamma-irradiation on both polymer samples was chain scission. The multiblock copolymer PEGd,lPLA presented higher sensitivity to irradiation treatment with respect to PLA, likely due to the presence of PEG in the matrix. The effect of gamma irradiation continues over a much longer period of time after gamma irradiation has been performed. It is suggested that the material reacts with oxygen to form peroxyl free radicals, which may further undergo degradation reactions during storage after irradiation.

PLGA microspheres for oral osteopenia treatment: preliminary "in vitro"/"in vivo" evaluation

The aim of this work was to prepare and to evaluate "in vitro"/"in vivo" microspheres based on poly(D,L-lactide-co-glycolide) copolymers containing ipriflavone, for the local treatment of oral bone loss. The first objective was the preparation and "in vitro" characterization of ipriflavone loaded microspheres, by emulsion/solvent evaporation method. Process parameters such as drug:polymer weight ratio, and molecular weight of copolymers, were also investigated. The second objective was to elaborate a suitable animal model of mandibular osteoporosis, to evaluate the efficacy of these microparticulate drug delivery systems. "In vivo" experiments were carried out on female rats, in which oral osteopenia was induced by gonadectomy and molar avulsion. Morphometric analysis of mandibular segment were carried out to quantify the development of oral osteopenia and the efficacy of drug loaded microspheres. Results showed that ipriflavone loaded PLGA microspheres can be successfully obtained with good "in vitro" characteristics, utilizing the emulsification/solvent evaporation method. "In vivo" experiments revealed that local administration of microspheres produced only mild inflammation on the injection site. Morphometric analyses showed, at the level of the third molar, a slight increase in spongy and total bone mass on rat jaw treated with microspheres with respect to control. Control animals exhibited a scarce degree of osteopenia demonstrating that this animal model is not suitable for this purpose.

Periodontal delivery of ipriflavone: new chitosan/PLGA film delivery system for a lipophilic drug

The aim of the present work was to design a film dosage form for sustained delivery of ipriflavone into the periodontal pocket. For this purpose, monolayer composite systems made of ipriflavone loaded poly(D,L-lactide-co-glycolide) (PLGA) micromatrices in a chitosan film form, were obtained by emulsification/casting/evaporation technique. Multilayer films, made of three layers of polymers (chitosan/PLGA/chitosan), were also prepared and compared to monolayer films for their "in vitro" characteristics. Morphology and physico-chemical properties of the different systems were evaluated. The influence of pH, ionic strength and enzymatic activity on film degradation, was also investigated. Significant differences in swelling, degradation and drug release were highlighted, depending on film structure and composition. In vitro experiments demonstrated that the composite micromatricial films represent a suitable dosage form to prolong ipriflavone release for 20 days.

Effect of nanoparticle encapsulation on the photostability of the sunscreen agent, 2-ethylhexyl-p-methoxycinnamate

The aim of this study was to investigate the influence of nanoparticle-based systems on the light-induced decomposition of the sunscreen agent, trans-2-ethylhexyl-p-methoxycinnamate (trans-EHMC). Ethylcellulose (EC) and poly-D,L-lactide-co-glycolide (PLGA) were used as biocompatible polymers for the preparation of the particulate systems. The "salting out" method was used for nanoparticle preparation and several variables were evaluated in order to optimize product characteristics. The photodegradation of the sunscreen agent in emulsion vehicles was reduced by encapsulation into the PLGA nanoparticles (the extent of degradation was 35.3% for the sunscreen-loaded nanoparticles compared to 52.3% for free trans-EHMC) whereas the EC nanoparticle system had no significant effect. Therefore, PLGA nanoparticles loaded with trans-EHMC improve the photostability of the sunscreen agent.

Evaluation of enzyme stability during preparation of polylactide-co-glycolide microspheres

This work was aimed at studying enzyme prolidase stability and its interactions with the reagents and the process conditions involved in preparation, by an emulsification process, of prolidase loaded poly(lactide-co-glycolide) (PLGA) microparticulate systems. Enzyme stability was tested with respect to contact with methylene chloride, ethyl acetate, PLGA polymers, and several agents used as emulsifiers such as polyvinyl alcohol (PVA), polyvinyl pyrolidone (PVP), carboxymethyl cellulose (CMC) and sodium oleate (NaOl). Enzyme stability to temperature and mechanical stirring was also evaluated. Prolidase-loaded PLGA microspheres were prepared and evaluated in terms of protein activity. The results obtained showed that the prolidase-loaded PLGA microspheres can be prepared only upon enzyme stabilization by addition of both BSA and MnCl(2) into its TRIS solution. Methylene chloride was the suitable organic solvent to be used in the double emulsion process, together with PVA as dispersing agent in the outer aqueous phase. Low temperatures during the emulsification step and very short process times are recommended, in order to maintain enzyme activity at its maximum. In these conditions spherical microspheres were obtained, releasing active prolidase for up to 15 days.

Enzyme loaded biodegradable microspheres in vitro ex vivo evaluation

Prolidase is a naturally occurring enzyme involved in the final stage of protein catabolism. Deficient enzyme activity causes prolidase deficiency (PD), a rare autosomal recessive inherited disorder whose main manifestations are chronic, intractable ulcerations of the skin, particularly of lower limbs. Although several attempts have been made towards the treatment of this pathology, a cure for this disease has yet to be found. The purpose of this work is to evaluate the possibility of enzyme replacement therapy through prolidase microencapsulation in biodegradable microspheres. The poly(D,L-lactide-co-glycolide) (PLGA) prolidase loaded microparticulate systems have been prepared utilizing the w-o-w double emulsion solvent evaporation method. They have been characterized "in vitro" by morphological analysis, total protein content and an in vitro dissolution test of active protein. "Ex vivo" evaluation of prolidase activity from the microspheres has been performed on cellular extracts of cultured skin fibroblasts from healthy subjects (controls) and from patients affected by PD. The results reported in this work on prolidase from pig kidney (available on the market) demonstrate the positive role of microencapsulation as a process of enzymatic activity stabilization inside PLGA microspheres achieving both in vitro and ex vivo active enzyme release. This formulation can be proposed as a parenteral depot drug delivery system.

Long-term release of clodronate from biodegradable microspheres

This paper describes the formulation of a biodegradable microparticulate drug delivery system containing clodronate, a bisphosphonate intended for the treatment of bone diseases. Microspheres were prepared with several poly(D,L-lactide-co-glycolide) (PLGA) copolymers of various molecular weights and molar compositions and 1 poly(D,L-lactide) (PDLLA) homopolymer by a water-in-oil-in-water (w/o/w) double emulsion solvent evaporation procedure. Critical process parameters and formulation variables (ie, addition of stabilizing agents) were evaluated for their effect on drug encapsulation efficiency and clodronate release rate from microparticles. Well-formed clodronate-loaded microspheres were obtained for all polymers by selecting suitable process parameters (inner water/oil volume ratio 1:16, temperature-raising rate in the solvent evaporation step 1 degree C/min, 2% wt/vol NaCl in the external aqueous phase). Good yields were obtained in all batches of clodronate microspheres (above 60%); drug encapsulation efficiencies ranged between 49% and 75% depending on the polymer used. Clodronate release from all copolymer microspheres was completed in about 48 hours, while those from PDLLA microspheres required about 20 days. The change of microsphere composition by adding a surfactant such as Span 20 or a viscosing agent such as carboxymethylcellulose extended the long-term release up to 3 months. Clodronate was successfully entrapped in PLGA and PDLLA microspheres, and drug release could be modulated from 48 hours up to 3 months by suitable selection of polymer, composition, additives, and manufacturing conditions.

Microparticulate drug delivery systems

Chitosan was proposed as a drug carrier for mucosal administration in ocular, buccal, nasal, gastroenteric and vaginal-uterine therapies based on its bioadhesive properties and biodegradability in vivo under the action of hydrolases. Examples are the delivery of acyclovir via ocular administration, and the delivery of 5-aminosalicylic acid to the colon. Microparticles may need to be cross-linked to retard their degradation in acidic media; yet cross-linking with glutaraldehyde introduces cytotoxic characteristics and depresses bioadhesion. Alternative cross-linking approaches are discussed along with the suitability of chitosan for the oral delivery of vaccines.

Hyaluronidase-injectable microparticles intended for the treatment of extravasation

Hyaluronidase is a protein whose enzymatic activity is successfully employed in extravasation therapy. Taking into account that several proteins (e.g. gelatin and albumin) have been employed as natural polymers for the preparation of microspheres, this work approaches a comprehensive investigation on hyaluronidase injectable microparticles. The goals are either to obtain a sustained release preparation of hyaluronidase or to use the enzyme as drug carrier. Microspheres have been prepared using a water-in-oil emulsification technique, and they have been crosslinked either by thermal or chemical means. Results show that hyaluronidase microspheres with good morphological characteristics can be obtained by this preparation method. Manufacturing variables influence the enzymatic activity of the microspheres, which can be highly preserved under mild experimental conditions. Moreover, the suitability of this enzyme as a microparticulate drug carrier has been shown by the successful encapsulation of hydrocortisone sodium succinate.

Evaluation of process parameters involved in chitosan microsphere preparation by the o/w/o multiple emulsion method

Chitosans are interesting biopolymers largely studied for applications in the medical and pharmaceutical fields. In this work, an o/w/o multiple emulsion technique was used for the preparation of hydrophobic drug loaded microspheres. Moreover, the influence of critical variables (concentration of acetic acid in the polymer solution and drug-polymer ratio) on microsphere morphology and drug content was evaluated. Two chitosans of different molecular weights and deacetylation degree were employed; ketoprofen, a non-steroidal anti- inflammatory drug, was chosen as the hydrophobic model drug. The multiple emulsion method produced well-formed microspheres with good yields. Acetic acid concentration in the polymeric solutions influenced particle size and drug content of the microspheres. The highest drug encapsulation efficiencies were obtained for the lowest theoretical drug/chitosan ratio.

[The regulation of drug prices in Italy]

Medicinal products price regulation in Italy has been discussed. The financial law n. 537/93 has deeply modified the criteria utilised to define the industrial medicaments prices. The authors analysed the implications derived from the variation from a fixed price system to a system based on the media of the european drug prices.

Antigravitropic activity of 2-(2-arylamino-1,2-dioxoethyl) benzoic acid methyl esters

Methylation of 1,3-dihydro-1-hydroxy-3-oxo-1-isobenzofurancarboxamides (A-I) yields 2-(2-arylamino-1,2-dioxoethyl)benzoic acid methylesters. The esters 1-7 allowed the evaluation of the intrinsic activity of 2-(2-arylamino-1,2-dioxoethyl)benzoic structure, to whom the antigravitropic effect of the carboxamides A-I may be probably assigned. The comparison of activities of methylesters 1-7 (B) and 8-14 (C) shows how conformational differences as those between the arylamino-1,2-dioxoethylic portion of B and the arylamino-2-oxoethylic portion of C may deeply effect phytotropin interaction with the receptor site.

Antimycotic 2-alkyldithio, 2-aralkyldithio, 2-aryldithiobenzamides

Some 2-alkyldithio, 2-aralkyldithio, 2-aryldithio benzoic acids, their methyl esters and N-monosubstituted amides were prepared and tested in vitro against Candida albicans and Trichophyton mentagrophytes. Some N-monosubstituted amides displayed activities similar to those of clotrimazole and pyrrolnitrin. Against Candida albicans, N-monosubstituted amides exhibited a generally higher activity than the corresponding N-monosubstituted amides of 2,2'-dicarboxydiphenyldisulfide.

Antimycotic agents: evaluation of some derivatives of 2-thiocyanobenzoic acid

The AA. have tested some amides, esters and thioesters of 2-thiocyanobenzoic acid for their antimycotic activity in vitro against fungal strains representative of human diseases. The results pointed out the remarkable antimycotic activities of 2-thiocyanobenzamides N-monosubstituted.

[Derivatives of 2-thiocyanobenzoic acid with antifungal activity]

A series of amides, esters and thioesters of 2-thiocyanobenzoic acid were synthesised and tested for antifungal activity in vitro and in vivo against various strains of fungus pathological to plants. The phytotoxicity against representative plants was studied in parallel. The substances were prepared by condensation of suitable mercaptobenzamides with cyanogen bromide or of 2-thiocyanobenzoyl chloride with amines, alcohols or mercaptans. This research showed in vitro antifungal activity of some N-monosubstituted amides and in vivo activity of some N-monosubstituted and N,N-disubstituted amides of 2-thiocyanobenzoic acid which have the same protective activity towards P. viticola as Zineb.

[Aryl esters of N-benzyldithiocarbamic acid with antimycotic activity]

Some aryl esters of N-benzyldithiocarbamic acid [substances (I leads to XVI)], in which S aryl substituents were hydrophylic or potentially hydrophylic groups, were tested for in vitro antifungal activity against the following strains: Candida albicans, Saccharomyces cerevisiae and Trichophyton mentagrophytes. The substances were prepared by condensation of benzylisothiocyanate with suitable benzenethiols. The results, given in Table I, show the marked activity as antifungal agents of the N-benzyldithiocarbamic acid aryl esters studied; the antifungal activity, connected with the N-benzyldithiocarbamic group, is only slightly influenced by the nature of the substituents.

[Anticryptogamic activity of some aryl esters of N-benzyldithiocarbamic acid]

Some aryl esters of N-benzyldithiocarbamic acid, characterized by the presence on the S-aryl group of hydrophilic or potentially hydrophilic groups were studied for anticryptogamic activity in vitro and in vivo. The substances were prepared by condensation of benzylisothiocyanate with suitable benzenethiols. The results showed the anticryptogamic activity of acylation derivatives of N-monosubstituted thiosalicylamides with the acyl of N-benzylthiocarbamic acid.

[Antifungal activity of diesters of 2-mercaptobenzene methanethiol]

Some diesters of 2-mercaptobenzenmethanthiol and of 2-(2-nitrophenyl)-1,3-benzodithiyne were prepared and tested for in vitro antifungal activity. The substances [Table I: substances (I leads to VIII)] were obtained by condensation of 2-mercaptobenzenmethanthiol with suitable reagents. The antifungal activity of the products was tested in vitro against the following strains: Candida albicans, Saccharomyces cerevisiae and Trichophyton mentagrophytes. It was found that antimycotic activity is shown by only some of the diesters of 2-mercaptobenzenmethanthiol with acyl alkylthiocarbamic groups (Table I). The diesters with aliphatic, aromatic, alkylcarbamic groups and the 2-(2-nitrophenyl)-1,3-benzodithiyne are inactive or only slightly active.

[Acaricidal, chemosterilant and insecticidal activity of triazine derivatives]

A large number of 1-aryl-3,3-dialkyl triazenes and 1,2-diphenyl triazenes variously substituted in the 3 position with OH and alkyl groups were prepared and studied for acaricide activity against Panonychus ulmi and chemosterilizing and insecticidal activity against Musca domestica. The results highlighted the marked chemosterilizing activity of 1-(2-methoxyphenyl)-3,3-di-n-propyltriazene and the interesting acaricidal activity of 1-(4-benzoylphenyl)-3,3-dimethyltriazene. The examination of such a large number of compounds for insecticidal activity allowed interesting conclusions to be drawn regarding structure/activity relationships.

[Benzenedithiol esters with antimycotic activity]

Some diesters of benzen-1,2-dithiol wit aliphatic and aromatic carboxylic acids were prepared and tested for in vitro antifungal activity. The diacetate and dipropionate of benzen-1,3- and 1,4-dithiol were used as comparison compounds. The substances (Table I; substances I leads to X) were obtained by condensation of benzenedithiols with suitable acylating agents. The fungistatic activity of the products was tested in vitro against the following fungal strains: Candida albicans, Candida tropicalis, Saccharomyces cerevisiae and Trichophyton mentagrophytes. The results show that the diester of benzen-1,2-dithiols with alkanoic acids (Table I) have marked antimycotic activity, much greater than that of clotrimazol. The diaroyl esters of benzen-1,2-dithiol and the diesters of benzen-1,3- and 1,4-dithiols are inactive or only slightly active.

[Preparation and study of the antimycotic activity of 2-substituted 1,3-benzodithiols]

A series of 1,3-benzodithiols substituted at position 2, obtained by condensation of benzene 1,2-dithiols with aldehydes and ketones, was studied for antifungal activity. The fungistatic activity of the compounds [Table I, II; (I leads to XXV)] was tested in vitro against the four strains: Candida albicans, Candida tropicalis, Saccharomyces cerevisiae and Trichophyton mentagrophytes. The results indicate at the 2-monosubstituted 1,3-benzodithiols are an interesting class of antifungal substances, the 2-phenyl substituted derivative (1) being of particular interest.

[The antimycotic activity of acyl derivaties of 2-oximino-1,3-benzodithiol]

A series of esters of 2-oximino-1,3-benzodithiol [substances (II leads to XV)] was prepared and tested for antifungal activity in vitro. The substances were obtained by condensation of 2-oximino-1,3-benzodithiol with suitable acylation agents. The fungistatic activity of the products was tested in vitro against the four strains: Candida albicans, Candida tropicalis, Saccharomyces cerevisiae and Trichophyton mentagrophytes. The results reported in the Table I show the interesting antimycotic activity observed for 2-oximino-1,3-benzodithiol, which is apparently connected with the presence of a free oximino group.

[Thiocarbamic and carbamic esters of benzenedithiols with antimycotic activity]

o-, m- and p-phenylen esters of some dithio and thiol carbamic acids N-monosubstituted were prepared and tested for in vitro antifungal activity. The substances studied [Tables I leads to III; substances (I leads to XXI) were all new and were prepared by the reaction of benzenethiols with suitable isothiocyanates or isocyanates. The fungistatic activity of the products was tested in vitro against the four following strains: Candida albicans, Candida tropicalis, Saccharomyces cerevisiae and Trichophyton mentagrophytes. The results show that the diesters of N-monosubstituted carbamic acids of benzen-1,2-dithhiol (Table I) have marked antimycotic activity, of the same order or greater than that of clotrimazol. Among the thiocarbamic and carbamic diesters of benzen-1,3- and 1,4-dithiol, the most active are the N-benzyl- and N-beta-phenyethyldithiocarbamic derivatives.

[Preparation and antifungal activity of carbamic and thiocarbamic esters of thiophenols]

A series of N-substituted carbamic and thiocarbamic esters of thiophenols [substances (I leads to XLII)] was prepared and tested for in vitro antifungal activity. The substances were obtained by condensation of thiophenols with suitable isocyanates and isothiocyanates. The antifungal activity of the products was tested in vitro against the following strains: Candida albicans, Candida tropicalis, Saccharomyces cerevisiae and Trichophyton mentagrophytes. The results obtained, given in the Table I, show that the carbamic and thiocarbamic esters of the thiophenols examined have marked antifungal activity. The results give some information on structure-activity relationships and also show that in general the derivatives of dithiocarbamic acid are more active than the bioisosteric derivatives of thiocarbamic acid. Of the compounds examined the most active were esters of N-benzyl and N-allyldithiocarbamic acid.

[S-acyl derivatives of thiosalicylamides and their anti-fungal activity. IV]

Some S-acyl derivatives of N-alkylthiosalicylamides [Table I, II: substances (I leads to XXXIII)] in which the acyl group on S in a carbamic or thiocarbamic N-monosubstituted group were prepared and tested in vitro for antifungal activity. All the substances which are not previously recorded were prepared by condensation of 2-mercapto-N-alkylbenzamides with suitable isocyanates or isothiocyanates. The fungistatic activity of the products prepared was tested in vitro against the two strains: Candida albicans and Trichophyton mentagrophytes. The results (Table I and II) show that the N-monosubstituted S-carbamoyl and S-thiocarbamoyl derivatives of N-monosubstituted amides of thiosalicyclic acid have marked in vitro antimycotic activity. Many derivatives have activity of the same order of magnitude as that of clotrimazole and of these the most active compound is 2-(N-phenylcarbamoylmercapto)-N,n-heptylbenzamide (XXVI).

[S-Acyl derivatives of thiosalicylamides having antifungal activity. II]

Some S-acyl derivatives of N-alkylthiosalicylamides [Table I: substances (I leads to XXXI)] were prepared and tested for antifungal activity. The substances, most of which had not been previously reported, were prepared by condensation of 2-mercapto-N-alkylbenzamides with suitable acylating agents. The antifungal activity of the compounds was tested in vitro against Candida albicans and Trichophyton mentagrophytes. For some compounds the was tested activity against the above strains fungicidal, Candida tropicalis and Saccharomyces cerevisiae. Many of the compounds proved to have high antifungal activity comparable with that of Clotrimazol. The results extended knowledge on the structure-antifungal activity relationships of this class of compounds. The compounds with the highest antifungal activity were: 2-acetylmercapto-N,n-heptylbenzamide (XXVIII); 2-acetylmercapto-5-Cl-N,n-propylbenzamide (XIV); 2-acetylmercapto-N,n-octylbenzamide (XXXI); 2-acetylmercapto-N,n-pentylbenzamide (XXV); 2-acetylmercapto-N,n-hexylbenzamide (XXVII).

[S-acylderivatives of thiosalicylamides with antifungal activity. I]

A series of S-acylderivatives of N-ethylthiosalicylamide (substances I leads to XXIII) was prepared and tested for in vitro antifungal activity. The substances, not previously reported, were prepared by the reaction of 2-mercapto-N-ethylbenzamide with suitable acylating agents. The fungistatic activity of the prepared products was tested in vitro against Candida albicans and Trichophyton mentagrophytes. The results given in Table I show that the S-acylderivatives of N-ethylthiosalicylamides have interesting antifungal activity. From examination of the results (Tables I and II) some information on the structure-activity relationship was obtained. 2-Acetylmercapto-N-ethylbenzamide (I) and 2-propionylmercapto-N-ethylbenzamide (III) proved the most active of the compounds tested.