Showing papers in "Acta Poloniae Pharmaceutica in 2006"

Cardiac glycosides in cancer research and cancer therapy.

Abstract: The well known and accepted mode of action of cardiac glycosides is inhibition of the ubiquitous plasma membrane Na+, K+-ATPase that leads to increased intracellular Ca2+ ion concentrations. Ca2+ ions play pivotal role in many signaling pathways including those regulating apoptosis. It has been suggested that some forms of cardiac glycosides inhibit proliferation and induce apoptosis in prostate cancer cells in clinically relevant concentrations. It was also found out that the degree to which cardiac glycosides inhibited cancer cell growth was correlated to topoisomerase II-inhibiting activity. Digitoxin at concentrations found in cardiac patients induced levels of DNA-topoisomerase II cleavable complexes similar to etoposide, a topoisomerase II poison widely used in cancer chemotherapy. Cardiac glycosides can also regulate one of the most potent angiogenesis promoting substances, fibroblast growth factor-2 (FGF-2), and may inhibit activation of the transcription factor NF-kappaB. FGF-2 and NF-kappaB are relevant targets for anticancer drugs. There is growing interest in evaluating the oleander products and possibly other cardiac glycosides as antineoplastic agents. The first of these therapies to be developed in the United States is a patented, water-soluble oleander extract called Anvirzel.

A comparison of theoretical methods of calculation of partition coefficients for selected drugs.

Abstract: Hundred ninety three drugs of different pharmacological activity were studied. Lipophilicity of a drug is one of the parameters, which influence its biological activity. The n-octanol-water partition coefficients were calculated for these compounds by use of different theoretical procedures (AlogPs, IAlogP, miLogP, ClogP, logP(Kowwin), and xlogP). Particular theoretical partition coefficients were compared with experimental n-octanol-water partition coefficients (logP(exp)) for all studied drugs. It was shown that experimental partition coefficients correlate the best with theoretical partition coefficients calculated by use of logP(Kowwin) and AlogPs methods. It was shown that it exists the possibility of the prediction of experimental n-octanol-water partition coefficients on the basis of logP(Kowwin), AlogPs, and ClogP for fifteen drugs (adrenalin, clobazam, 5,5-dimethylbarbituric acid, ethyl nicotinate, fluphenazine, ibuprofen, methyllorazepam, pimozide, prednisolone, promethazine, spironolactone, surital, theophylline, triamterene, and trimethoprim).

Evaluation of zidovudine encapsulated ethylcellulose microspheres prepared by water-in-oil-in-oil (w/o/o) double emulsion solvent diffusion technique.

Abstract: The preparation of zidovudine-loaded ethylcellulose microspheres by w/o/o double emulsion solvent diffusion method with high entrapment capacity and sustained release is described. A mixed solvent system (MSS) consisting of acetonitrile and dichloromethane in a 1:1 ratio and light liquid paraffin was selected as primary and secondary oil phases, respectively. Span 80 was used as the secondary surfactant for stabilizing the external oil phase. Spherical free flowing microspheres were obtained. The prepared microspheres were characterized by entrapment efficiency, in vitro release behavior, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The drug-loaded microspheres showed 32 - 55% entrapment capacity. The in vitro release profile could be altered significantly by changing various processing and formulation parameters to give sustained release of drug from the microspheres. The DSC thermograms confirmed the absence of any drug-polymer interaction. SEM studies showed that the microspheres were spherical and porous in nature. The in vitro release profiles from microspheres of different polymer-drug ratios were best fitted to Higuchi model with high correlation coefficient and the n value obtained from Korsmeyer-Peppas model was ranged between 0.23 - 0.54. The drug release was found to be diffusion controlled mechanism.

Preparation and evaluation of modified release ibuprofen microspheres with acrylic polymers (Eudragit) by quasi-emulsion solvent diffusion method: effect of variables.

Abstract: The aim of this study was to prepare and evaluate microspheres containing ibuprofen. Microspheres were prepared by modified quasi-emulsion solvent diffusion method. The influence of formulation factors (drug-polymer ratio, volumes of solvent, polyvinyl alcohol concentration and type of polymer) on the morphology, particle size distribution, drug loading capacity, micromeritical properties and the in vitro release characteristics of the microspheres were investigated. Physical characterizations of ibuprofen microspheres were also carried out using scanning electron microscopy, X-ray diffractometry and IR spectrophotometry. It was found that the yield of preparation was dependent on the initial temperature gradient between the emulsion phases. When there was an initial difference of temperature between the aqueous phase and dispersed emulsion phases, yield of preparation was increased distinctly. The drug loading capacities were very high for all formulations of the microspheres which were obtained. Mean particle size changed by changing the drug-polymer ratio, volumes of solvent or polyvinyl alcohol concentration. The flow properties were much improved over those of the original crystals. In vitro dissolution results showed that the release rate of ibuprofen was modified in all formulations. Although ibuprofen release rates from Eudragit RS microspheres were very slow, they were fast from Eudragit RL microspheres. These results observed that if Eudragit RS and Eudragit RL are used in combination, optimum release profiles may be obtained.

Formualtion and evaluation of floating drug delivery system containing clarithromycin for Helicobacter pylori.

Abstract: Floating matrix tablets are designed to prolong the gastric residence time after oral administration, at a particular site and controlling the release of drug especially useful for achieving controlled plasma level as well as improving bioavailability. With this objective, floating dosage form containing clarithromycin as drug was designed for the treatment of Helicobacter pylori. Tablets containing hydroxypropylmethylcellulose (HPMC), drug and different additives were compressed using wet granulation and D-optimal design technique. The study shows that tablet composition and mechanical strength have great influence on the floating properties and drug release. Incorporation of gas-generating agent together with polymer improved drug release, besides optimal floating (floating lag time 10 h). The drug release was sufficiently sustained (more than 8 h) and anomalous diffusion as well as zero-order was confirmed. Optimization of the evaluating parameters with 'design expert' software was employed to get final optimized formulation. The optimized formulation was obtained using 62.5% clarithromycin, 4.95% HPMC K15M, 18.09% HPMC K4M, 12.96% sodium bicarbonate which gave floating lag time 10 h, in vitro release profile very near to the target in vitro release profile and follows anomalous diffusion as well as zero order pattern of release.

Validation of HPLC method for determination of atorvastatin in tablets and for monitoring stability in solid phase.

Abstract: A rapid high performance liquid chromatographic method was developed and validated for determination of atorvastatin in pharmaceutical dosage forms, and for evaluation of its stability in the solid phase. Separation of atorvastatin was successfully achieved on a C-18 column utilizing water--acetonitrile at the volumetric ratio of 48:52, adjusted to pH 2.0 with 80% ortho-phosphoric acid. The detection wavelength was 245 nm. The method was validated and the response was found to be linear in the drug concentration range of 0.04 mg/mL - 0.4 mg/mL. The mean values +/- RSD of the slope and the correlation coefficient were 8.192 +/- 0.260 and 0.999, respectively. The RSD values for intra- and interday precision were < 1.00% and 0.90%, respectively. The degradation kinetic of atorvastatin at 363 K in a relative humidity of 76.4% was observed to be autocatalytic first order reaction. The kinetic parameters were as follows: k (where k represents the velocity constant; s(-1)) = (1.42 +/- 0.19) 10(-6); t(0.5) (where t(0.5) represents the time needed for a 50% decay of atorvastatin; days) = 32.82 +/- 0.9; t(0.1) (where t(0.1) represents the time needed for a 10% decay of atorvastatin; days) = 13.86 +/- 0.8.

Preliminary evaluation of antioxidant activity of some 1-(phenoxyethyl)-piperazine derivatives.

Abstract: The antioxidant properties of appropriate 1-(phenoxyethyl)-piperazine derivatives possessing significant hypotensive activity in normotensive rats were measured in human venous blood samples, in vitro. Ferric reducing ability of plasma (FRAP) was measured in plasma, superoxide dismutase (SOD) and catalase (CAT) activities were determined in red blood cell hemolysates. Antioxidant profile of 1-(phenoxyethyl)-piperazine derivatives was compared to Trolox and Resveratrol. The compounds were investigated in concentrations from 10(-8) to 10(-4) mol x L(-1). The most promising compounds were 1-[(4-methyl)- and 1-[(2,6-dimethyl)-phenoxyethyl]-piperazine derivatives [1, 2] which increased SOD activity and total antioxidant capacity (TAC). An addition of chlorine atom to methyl-phenoxy moiety decreased antioxidant properties.

Steroidal glycosides from the underground parts of Allium ursinum L. and their cytostatic and antimicrobial activity.

Abstract: The aim of this study was the isolation and structural elucidation of steroidal glycosides from the underground parts of ramson Allium ursinum L. The structures of the isolated compounds were established based upon chromatographic methods and 1D- and 2D-NMR, MS and IR analyses. The mixture of two steroidal saponins: (25R)-spirost-5-en-3b-ol tetrasaccharide and (25R)-spirost-5, 25(27)-dien-3b-ol tetrasaccharide, along with a 3-hydroxypregna-5,16-dien-20-one glycoside were identified. The results of in vitro cytotoxic activity of the mixture of spirostanol saponins against cell lines melanoma B16 and sarcoma XC and human fibroblasts HSF are also reported. The spirostanol saponins mixture was investigated to determine its in vitro antimicrobal activity against Trichophyton mentagrophytes and Microsporum canis.

Anti-inflammatory activity of Achillea and Ruscus topical gel on carrageenan-induced paw edema in rats.

Abstract: The anti-inflammatory activity of Achillea and Ruscus extracts was studied in comparison with diclofenac sodium topical gel (diclosal Emulgel), using the carrageenan induced paw edema model in Albino rats. Gel formulation was prepared containing 6% of each extract in gel base, namely sodium carboxymethylcellulose (NaCMC). The kinetics of drug release from the prepared formulation was studied separately in each case. Results showed that the release follows the Higuchi square root equation. The pharmacological screening revealed that the percent reduction of edema for Achillea extract and Ruscus extract were 48.1% and 18.8%, respectively, while diclosal Emulgel produced 47% reduction of edema.

Determination of ellagic acid in pseudofruits of some species of roses.

Abstract: Ellagic acid (EA) is known as a naturally occurring dietary antimutagen and anticarcinogen with strong antioxidant and anti-inflammatory activities. An SPE RP HPLC method was optimized and applied for identification and determination of ellagic acid in hips of fourteen species of roses, wildly growing in Poland. A large amount of total EA, ranged from 487.2 to 1065.2 microg/g of dry material was found. The results suggest that studied materials are good sources of dietary ellagic acid and could be used as a natural antioxidant and functional food.

Synthesis and anticonvulsant properties of new N-phenylamino derivatives of 2-azaspiro[4.4]nonane, 2-azaspiro[4.5]decane-1,3-dione and 3-cyclohexylpyrrolidine-2,5-dione. Part IV.

Abstract: To continue our systematic SAR studies a series of N-phenylamino derivatives of 2-aza- spiro(4.4)nonane-, 2-azaspiro(4.5)decane-, 6-methyl-2-azaspiro(4.5)decane-1,3-dione and 3-cyclohexylpyrroli- dine-2,5-dione were synthesized and tested for their anticonvulsant activity in the maximum electroshock seizure (MES) and subcutaneous metrazole seizure threshold (sc. Met) tests. Among those molecules the most potent were N-(4-methylphenyl)-amino-2-azaspiro(4.4)nonane-1,3-dione (V), N-(2-trifluoromethylphenyl)- amino-2-azaspiro(4.4)nonane-1,3-dione (VI), N-(3-methylphenyl)-amino-2-azaspiro(4.5)decane-1,3-dione (VIII) and N-(4-methylphenyl)-amino-6-methyl-2-azaspiro(4.5)decane-1,3-dione (XIV), which inhibited the seizures mainly in the sc. Met test. The obtained results revealed that anticonvulsant activity depended on the presence and the position of the methyl or trifluoromethyl groups at the aryl moiety, as well as the size and the manner of attachment of the cycloalkyl system at the position-3 of the pyrrolidine-2,5-dione ring.

Anti-inflammatory and gastroprotective properties of some chalcones.

Abstract: The synthesis of 1,3-diaryl propen-1-ones (chalcones) by the Claisen-Schmidt condensation between acetophenones and benzaldehydes in potassium hydroxide/methanol medium at room temperature yielded: 1-(4-nitrophenyl)-3-(2,4,6-trimethoxyphenyl)propen-1-one (3a), 1-(4-nitrophenyl)-3-(3-bromophenyl)propen-1one (3b), 1-(4-methoxyphenyl)-3-(3-bromophenyl)propen-1-one (3c), 1-(4-methoxyphenyl)-3-(2,4,6-trimethoxyphenyl)propen-1-one (3d), 1-(2,4-dihydroxyphenyl)-3-(phenyl)propen-1-one (3e), 1-(4-nitrophenyl)-3-(4-chlorophenyl)propen-1-one (3f) which were evaluated for anti-inflammatory activity at doses of 20, 40 and 80mg/kg. The compounds were found to be effective inhibitors of carrageenan-induced rat paw edema in Wistar rats and this activity was dose dependent and increased between the third and fourth hour. The gastroprotective activity of the compounds was investigated (using 200 mg/kg acetylsalicylic acid-induced ulceration) in Wistar rats at a single dose of 100 mg/kg for all the compounds synthesized and compound 3d had significant activity (p<0.001) comparable to cimetidine. The compounds were found to have anti-inflammatory and anti-ulcer activities at the doses employed.

Flavonoid aglycones and phytosterols from the Erigeron acris L. herb.

Abstract: Four flavonoid aglycones (apigenin, kaempferol, luteolin, quercetin) were isolated from methanolic extract from the herb of Erigeron acris L (Asteraceae) In this extract five phytosterols (campesterol, chon- drillasterol, stigmast-7-en-3-ol(5α,3α), stigmasterol and spinasterone) were also identified

Comparative study of phenolic acids in pseudofruits of some species of roses.

Abstract: A free and liberated by acid and alkaline hydrolysis phenolic acids from the hips of fourteen species of wildly growing roses were identifed and determined using SPE RP HPLC method. Eleven major phenolic acids (gallic, protocatechuic, gentisic, p-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, ferulic. p-hydroxyphenylacetic, salicylic) were quantitatively investigated. The amount of individual compounds ranged from 0.2 mg/g to 303.2 mg/g of dry material. Conjugated forms of phenolic acids were predominated in the fruits and they were hydrolyzed mainly to gallic acid (93-303 mg/g in dry plant material). The total amount of phenolic acid after hydrolyses was from 186.4 mg/g (R. inodora) to 466 mg/g (R. rugosa) of dry weight of plant material.

In vitro dissolution kinetic study of theophylline from hydrophilic and hydrophobic matrices.

Abstract: Oral dosage forms containing 300 mg theophylline in matrix type tablets, were prepared by direct compression method using two kinds of matrices, glycerylbehenate (hydrophobic), and (hydroxypropyl)methyl cellulose (hydrophilic) The in vitro release kinetics of these formulations were studied at pH 68 using the USP dissolution apparatus with the paddle assemble The kinetics of the dissolution process were studied by analyzing the dissolution data using four kinetic equations, the zero-order equation, the first-order equation, the Higuchi square root equation and the Hixson-Crowell cube root law The analysis of the dissolution kinetic data for the theophylline preparations in this study shows that it follows the first order kinetics and the release process involves erosion / diffusion and an alteration in the surface area and diameter of the matrix system, as well as in the diffusion path length from the matrix drug load during the dissolution process This relation is best described by the use of both the first-order equation and the Hixson-Crowell cube root law

The influence of simvastatin at high dose and diltiazem on myocardium in rabbits, the biochemical study.

Abstract: 3-Hydroxy-3-methyl-glytaryl coenzyme A (HMG-CoA) reductase inhibitors ("statins") have been proved to be extremely useful in the management of hypercholesterolemia, as well as in prevention of primary and secondary coronary heart disease. However, they may produce rare but severe muscle-related symptoms such as myopathy and rhabdomyolysis. Recent findings in vitro have shown that statins can reduce cardiomyocyte viability. The exact mechanism of statin myotoxicity still remains unclear. Diltiazem as CYP3A4 inhibitor, is a well recognized risk factor of skeletal muscles myopathy, if co-administered with simvastatin. It is not known whether such interaction affects myocardial efficiency causing biochemical changes. The experiments were performed on thirty six New Zealand white rabbits. The animals were divided into four groups receiving: 0.2% MC (control group): diltiazem (5 mg/kg); simvastatin (50 mg/kg) or diltiazem + simvastatin, daily for 14 days (po). The following biochemical parameters were estimated: creatine kinase (CK), serum transaminases (ALT and AST), as well as myocardial injury markers: troponin I (Tnl) and creatine kinase MB (CK-MB). Simultaneous administration of simvastatin and diltiazem caused 23-fold increase (p < 0.01), in rabbit serum CK levels and 20-fold increase (p = 0.056) in TnI levels, as compared to the initial values. Also in these rabbits significant increase in CK (12411,60 vs 839.87 IU/L) and TnI (0,26 vs 0,014 ng/mL), as compared to control group were observed. Significant increase in CK (12411,60 vs 1100,92 IU/L) and TnI (0,26 vs 0,012 ng/mL), as compared to diltiazem alone were noted, too. This may suggest another mechanism of drug-drug interaction than the one based on CYP3A4 inhibition if the impact on cardiac or skeletal muscle is considered.

Analysis of aqueous extract of Inonotus obliquus.

Abstract: Water-soluble melanin complexes were extracted with hot water from Inonotus obliquus fungus. They were characterized before and after reaction with diluted hydrochloric acid. The organic components as products of degradation of melanin complexes were separated by column chromatography and analyzed by GC-MS method.

Biotransformation of praziquantel by human cytochrome p450 3A4 (CYP 3A4).

Abstract: Praziquantel (PZQ) is the drug of choice for the treatment of human schistosomiasis. It is estimated that about 200 million people in the world are currently affected by this tropical disease. Now PZQ is also used in malaria treatment. The usefulness of PZQ as antimalarial drug is important because of rapid development of resistance to usually applied drugs. PZQ undergoes extensive metabolism in human body, mainly in liver by two cytochrome P-450 isoenzymes 2B1 and 3A. As the result of these biotransformations numerous mono- and dihydroxylated derivatives in B, C and D ring are formed. Two metabolites have been fully identified and described, as cis- and trans-4-hydroxypraziquantel. Up to now there were created many different in vitro and in vivo models of PZQ biotransformations. In vitro model of PZQ biotransformation was created by using human cytochrome P-450 3A4 expressed in Eschelichia coli and Saccharomyces cerevisiae. In the first experiment we have used human cytochrome P-450 3A4 from Escherichia coli (isolated on NTA-column). In the second experiment microsomes isolated from Saccharomyces cerevisiae containing coexpressed human CYP 3A4, human CYP-reductase and human cytochrome b5 were used. The reactions were monitored by HPLC and MS.

Determination of metoprolol and hydrochlorothiazide by derivative spectrophotometric method in pharmaceutical preparations.

Abstract: A procedure for simultaneous determination of metoprolol and hydrochlorothiazide in tablets by employing derivative spectrophotometry, "zero-crossing" method was developed. The third order derivative absorption spectra at lambda approximately 281 nm were used for metoprolol and the first order derivative spectra at lambda approximately 282 nm were used for hydrochlorothiazide. No interferences were found between both determined constituents and those of matrix. A good accuracy and precision of simultaneous determination of metoprolol and hydrochlorothiazide were confirmed by statistical analysis. The recovery of individual constituents under established conditions is very high and ranges from 98.79% to 99.39%. Linearity is maintained within a wide concentration range from 100.0 microg mL(-1) to 300.0 microg mL(-1) and from 12.5 microg mL(-1) to 37.5 microg mL(-1) for metoprolol and hydrochlorothiazide, respectively. The detection limit is 5.0 microg mL(-1) for metoprolol and 1.5 microg mL(-1) for hydrochlorothiazide. The corresponding quantitation limits are 15.0 microg mL(-1) for metoprolol and 4.5 microg mL(-1) for hydrochlorothiazide.

Studies on pyrazine derivatives. XLVII. Synthesis and antibacterial activity of novel pyrazine derivatives with amidoxime moiety.

Abstract: The new pyrazine derivatives exhibiting an antibacterial activity have been synthesized. Initial amidoxime 1 was obtained in the reaction of pyrazinecarbonitrile with hydroxylamine. Upon treatment of amidoxime with methyl iodide O-methyl derivative 2 was formed. Both amidoximes were transformed into imidoyl chlorides 3, 4. Then the chloride atom in those derivatives was substituted with various secondary amines giving appropriate oximes 5-18 and O-methyl-oximes 19 and 20. The obtained compounds were tested in vitro for their tuberculostatic activity. The inhibiting concentration (MIC) values were within 25-100 microg/mL. Their activity towards 25 strains of anaerobic and 25 strains of aerobic bacteria was also studied. Three compounds exhibited activity against both types of bacteria.

Cancer chemopreventive agents-drugs for the 21st century?

Abstract: After a quarter of a century of rapid advances in cancer research, the focus of oncological drug development has shifted from cytotoxic chemotherapy to rationally designed agents that target specific molecules associated with malignant cells or their environment. Carcinogenic process is driven by mutation, but there are many epigenetic variables which could be the targets of early intervention before invasion and metastasis occur. Chemoprevention is the inhibition, retardation or reversal of carcinogenic processes by pharmacological or natural agents targeting these pathways in high-risk individuals. This approach was developed more than 30 years ago and its credibility was enhanced by the positive results of clinical trials involving subjects with risk of developing breast cancer and colon tumors. So far however, not many clinical trials provided satisfying results, not only because of the lack of efficacy or side toxic effects of chemopreventive agents, but also the lack of precise biomarkers monitoring their effects. In spite of all these obstacles, the field of cancer chemoprevention is very active, not only because of its accelerating scientific base, but also because is vitally needed. New information from molecular studies has identified specific molecular targets for chemopreventive agents. These include regulatory molecules such as Nrf2, epidermal growth factor receptor kinases, components of the Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway, nuclear factor-kappaB, and cyclin D. The development of new drugs for the control of these targets that are both safe and effective will be important for the future of cancer chemoprevention.

Isolation and characterization of 3-carbomethoxypyridine from the leaves of Pyrenacantha staudtii Hutch and Dalz (Icacinaceae).

Abstract: Pyrenacantha staudtii is a medicinal plant used widely in the West African sub-region particularly in Nigeria for the treatment of threatened abortion and dysmenorrhea. This study reports for the first time the chemical isolation and characterization of 3-carbomethoxypyridine from one of the active fractions of the methanolic extract of Pyrenacantha staudtii leaves. The crude methanolic extract was subjected to accelerated gradient chromatography (AGC) to give various fractions. One of the active fractions was further subjected to a reversed phase lobar column chromatography to give the alkaloidal compound using methanol : water as solvent system. The structure was unequivocally determined by physical, chemical and spectral techniques.

Fluorimetric detection of aldehyde dehydrogenase activity in human tissues in diagnostic of cancers of oral cavity.

Abstract: Aldehyde dehydrogenase (ALDH) is known to be susceptible to oxidation, and its assays require stabilization of the enzyme by thiols. Application of the fluorimetric method to assay the ALDH activity in human saliva demonstrated significant differences between procedures utilizing glutathione (GSH) and dithiothreitol (DTT) as stabilizing agents. It has been recently shown that average aldehyde dehydrogenase (ALDH3A1) activity in cancerous (oral cavity cancer) patients' tissues was higher than that found in the control group, what may indicate induction of tumor-specific ALDH.

Phenolic acids in the flowers of Althaea rosea var. nigra

Abstract: Distribution of phenolic acids in the flowers of Althaea rosea var. nigra has been studied by 2D-TLC and HPLC methods. The phenolic acids occurring in these fractions have been identified as ferulic, vanillic, syringic, p-coumaric, p-hydroxybenzoic, p-hydroxyphenylacetic and caffeic acids. By means of the HPLC methods the contents of major phenolic acids were estimated. From among the phenolic acids analyzed the syringic, p-hydroxybenzoic and p-coumaric acids are dominant. Total content of phenolic acids was determined by the Arnov's method.

Unnatural D-amino acids as building blocks of new peptidomimetics.

Abstract: offers many advantages as newly designed drugs. The benefits include enhanced stability to proteolytic enzymes, better transport through cellular membranes, increased bio-availability, changing agonist to antagonists potency and higher affinity in ligand-receptors interactions. D-amino acids are used to design and obtain new peptidomimetics by their incorporation in place of the natural L-amino acids, either at a specific position, or throughout the whole peptide. D-phenylalanine is one of the preferred amino acids. Addition of hydrophobic phenyl ring results in better transport properties of peptidomimetics through cellular membranes and better enzymatic stability (1, 2). Up to now D-phenylanine and derivatives have been successfully used in design of new efficient peptidomimetics. 4-fluoro-D-phenylalanine derivative implicate in new agonist of melanocortin receptors (MCRs). A common structural feature present in all endogenous ligands (MSH, ACTH) of the melanocortin receptors (MCRs) is His-Phe-Arg-Trp sequence, which has been identified as the minimal peptide fragment necessary for activating the receptors. Further structural modifications toward α-MSH showed that inverting Phe to the D-configuration resulted in an analog with enhanced potency and enzymatic stability. Replacement of the phenyl ring of D-Phe side chain in one of His-DPhe-Arg-Trp analogue with 4-fluorophenyl group led to potent MCRs agonist with enhanced selectivity (3). Synthetic decapeptides, Cetrorelix and Abarelix belong to third-generation of modified gonadotropin releasing hormone (GnRH) antagonists and contain in their structures D-4-chlorophenylalanine. GnRH, a linear decapeptide synthesized by gonadotropic cells of hypothalamus, is a central mediator of the human reproductive axis. Cetrorelix and Abarelix reveal high antagonistic activity against naturally occurring GnRH and are used for treatment of sex hormone-dependent disorders (4, 5). Another important example of peptidomimetic with D-phenylalanine presence is Octreotide ñ a synthetic somatostatin analogue with similar but more prolonged pharmacological effects. Octreotide is used to treat acromegaly and also to reduce flushing episodes and watery diarrhoea caused by cancerous tumors (carcinoid syndrome) (6). Furthermore, D-amino acidñcontaining peptides are especially important as pharmaceuticals due to their strong antibacterial activity. Many of them (Bacitracin A, Fungisporin, Gramicidin S, Tyrocidine, Polymyxin,) contain D-phenylalanine (2). In the present work we report the application of hydantoinase method to obtain D-phenylalanine derivatives. Hydantoinase method consist of three steps:

The FAS-related apoptosis signaling pathway in the prostate intraepithelial neoplasia and cancer lesions.

Abstract: An aim of the study was to determine the protein expression of the FAS-related apoptosis signaling pathway (FADD-FAS Associating Protein with Death Domain, PRO-CASPASE-8 and CASPASE-8), which are responsible for signal transduction to trigger programmed cell death (apoptosis) in cancer and Prostatic Intraepitelial Neoplasia (PIN). 20 specimens from prostate cancer patients treated with radical prostatectomy were inwestigated. 8 cancers were diagnosed as G-2 and 12 as G-3. 14 samples were described as poorly differentiated, high Gleason score (> or = 7). Control group consisted of prostate specimens from autopsy of 3 young men. Specimens were fixed in 10% buffered formaldehyde and immersed in paraffin. Haematoxylin and eosin staining was done. Monoclonal antibodies to FADD & CASPASE-8 (Novocastra, UK) were used to immunohistochemical study, according to streptavidine-biotin method. Semiquantitive method described protein expression. Expression index (EI) was calculated as a percent of positive FADD or CASPASE-8 cells to total cells in the specimen. Statistical analysis was performed with the Student t-test (p < 0.05). Normal prostate tissue was negative in both, FADD and CASPASE-8 immunohistochemistry staining. PIN & prostate cancer lesions were found to strongly express of FADD & CASPASE-8 proteins. Expression of FADD in cancer lesions was 66,5+/-27,8% and 59,8+/-19,0% vs. 56,8114,8% HGPIN and LGPIN, respectively. Expression of CASPASE-8 in cancer lesions was 64,1 + 23,4% and 61,5+/-15,0% vs. 48,0+/-17,6% HGPIN and LGPIN, respectively. PIN & prostate cancer lesions are characterized by similar high expression of proteins responsible for signal transduction to induce apoptosis. The mediators of apoptotic signal can be very important in prostate cancer prophylaxis and management.

Thermal stability of 1,4-dihydropyridine derivatives in solid state

Abstract: The effect of temperature and air humidity on the stability of 7 derivatives of 1,4-dihydropyridine (nifedipine, nisoldipine, nitrendipine, nimodipine, nicardipine, felodipine and amlodipine) in solid state has been studied by accelerated testing. Quantitative analysis of the compounds studied was made by UV spectrophotometry, identification of the thermodegradation products and reference to the standard were made by thin layer chromatography (TLC), UV spectra and the reaction with KMnO4. Thermodegradation of the derivatives studied was found not to occur in dry air, whereas at air humidity it occurred according to the first order reaction at a similar rate for all derivatives. The main product of thermodegradation of the derivatives with the nitro substituent was a nitrozoderivative formed as a result of dihydropyridine ring aromatisation accompanied by water molecule elimination.