bluuebunny/crossref_metadata_2025 huggingface dataset:
Conformational analysis of tripeptide Ac-Lys-Pro-Val-NH2, COOH-terminal sequence of alpha-MSH
Authors: Chavatte Philippe , Yous Saïd , Lesieur Daniel , Hénichar Jean-Pierre
Published: July 2003

Alpha-melanocyte stimulating hormone (alpha-MSH) is an endogenous linear tridecapeptide which interacts with the melanocortin receptors (MC1-R to MC5-R) to mediate its biological effects. Antipyretic and anti-inflammatory activities of alpha-MSH are due to the COOH-terminal peptide sequence, Lys-Pro-Val (alpha-MSH[11–13]). This tripeptide might be useful as a therapeutic agent in the control of fever and inflammatory reactions. With this aim, a theoretical conformational study of the tripeptide has been carried out using molecular dynamics. The obtained conformational space has been classified into families according to the letter-code convention to partition the φ-ψ map. The lowest energy conformations of each family were used as templates to design six models of conformationally constrained non-peptide analogues.
Studies on the reactivity of a tertiary allylic alcohol in an acetophenonic series, a model for natural products synthesis
Authors: Hélesbeux J J , Séraphin D , Duval O , Richomme P , Bruneton J
Published: July 2003

The synthesis of benzopyranic simplified analogues of dibenzopyranic natural compounds is described, together with the access to a precursor of a new furobenzopyranic natural product. These natural products have anti-cancer activity. The 1,3-diacetoxy-2-acetyl-4-(3-hydroxy-3-methylbut-1-enyl)benzene synthone is used as a common precursor to these structures.
5-Substituted 3,4-dihydro-3-amino-2H-1-benzopyran derivatives: synthesis and interaction with serotoninergic receptors
Authors: Rezaie R , Joseph B , Bremner J B , Delagrange P , Kopp C , Misslin R , Pfeiffer B , Renard P , Guillaumet G
Published: July 2003

A new series of 3,4-dihydro-3-amino-2H-1-benzopyran derivatives (1 and 2) bearing various substituents on the 5-position was successfully prepared via palladium-mediated cross-coupling reactions. Some of the new compounds showed high affinity for 5-HT1A and 5-HT7 receptors. The best affinity for the 5-HT1A and 5-HT7 receptors was obtained for 2b (Ki = 0.3 nM for 5-HT1A and 3.1 nM for 5-HT7). The anxiolytic activity of compound 2b was evaluated.
Pharmacokinetic study on gastrointestinal absorption of insulinomimetic vanadyl complexes in rats by ESR spectroscopy
Authors: Fugono Jun , Yasui Hiroyuki , Sakurai Hiromu
Published: July 2003

Recently, we have shown that oral administrations of vanadyl (+ 4 oxidation state of vanadium) complexes normalize the blood glucose level of streptozotocin-induced diabetic rats (STZ-rats). To develop clinically useful insulin-mimetic vanadyl complexes, clarification of the pharmacokinetic features of vanadyl compounds is essential. First, we investigated the absorption processes of three compounds, an ionic form of vanadyl sulfate (VS) and the complex forms of bis(picolinato)oxovandium(IV) (VO(pic)2) and bis(6-methylpicolinato)oxovanadium(IV) (VO(6mpa)2), from the gastrointestinal tract of healthy rats. The concentration curves of paramagnetic vanadyl species in the blood of rats after oral administration of these compounds, as monitored by X-band electron spin resonance (ESR) spectroscopy, exhibited biphasic increasing patterns, indicating that these compounds were absorbed from more than two sites in the gastrointestinal tract. The bioavailability of the compounds was enhanced in the following order on both oral and intraperitoneal administration: VO(6mpa)2 > VO(pic)2 > VS. In addition, bioavailability of the VO(6mpa)2 on ileal administration was enhanced compared with that using other administration sites such as the stomach and jejunum, and resulted in an enhancement about 1.8 fold that compared with oral administration. On the basis of these results, we concluded that the bioavailability of the complex is enhanced most effectively by delivery of the VO(6mpa)2 complex to the ileum.
Hexarelin - evaluation of factors influencing oral bioavailability and ways to improve absorption
Authors: Westberg Carina , Benkestock Kurt , Fatouros Angelica , Svensson Marianne , Sjöström Brita
Published: July 2003

Hexarelin, a hexapeptide with growth hormone-releasing activity, has been found in man to have a biological bioavailability (estimated from growth hormone levels) of 0.3 ± 0.1 % after oral administration. The cause of the low oral efficacy of hexarelin and means of improving its absorption have been evaluated. It was found that hexarelin was degraded in the presence of the contents of the intestine. The metabolite was identified as hexarelin deamidated at the lysine residue. The degradation of hexarelin in the contents of rat ileum was inhibited by the addition of chymostatin, Pefabloc SC, EDTA, and EGTA. Furthermore, the presence of pancreatic proteases from pancrease substitute drugs caused a degradation of hexarelin that could be inhibited by the addition of Pefabloc SC. The same hexarelin metabolite that was found with the contents of rat ileum was found in the presence of human, porcine and bovine trypsin. Hexarelin permeability across rat ileum and in Caco-2 cell monolayers was low. An increase in hexarelin permeability was observed in the presence of different permeability enhancing agents.
The use of polymeric solid phase extraction and HPLC analysis for the determination of ranitidine in routine plasma samples obtained from paediatric patients
Authors: Hare L G , Millership J S , Collier P S , McElnay J C , Carson D J , Shields M S
Published: July 2003

A sensitive HPLC method for the determination of ranitidine in small-volume (0.5 mL) paediatric plasma samples is described. Plasma samples were extracted using a simple, rapid solid phase extraction (SPE) technique developed using disposable copolymer packed SPE cartridges. Chromatographic separation was achieved by reverse-phase HPLC with isocratic elution using a μBondapak C18 column and a phosphate buffer (10 mm, pH 3.75)-acetonitrile (87:13 v/v) mobile phase with UV detection at 313 nm. The HPLC system exhibited linearity in the range 8–800 ng mL−1. Intraday % CV and % bias values were in the range 1.28–8.09% (% bias %-4.33 to %-0.87) and interday % CV and % bias values were in the range 0.73–15.28% (% bias %-1.80 to +1.65). The limits of detection and quantitation obtained were 2 ng mL−1 and 8 ng mL−1, respectively, and ranitidine extraction recoveries from plasma ranged from 92.30 to 103.88%. In this study, the developed HPLC and SPE methodologies have been successfully applied to the determination of ranitidine concentrations in 68 paediatric plasma samples. The sampled population was drawn from patients already receiving the study drug therapeutically. Patients recruited had received ranitidine by two main routes - oral and intravenous. The plasma concentrations of ranitidine encountered in paediatric samples following oral or intravenous administration of a range of prescribed doses are presented graphically. These profiles are based on analysis of the first 68 plasma samples obtained from the first 35 patients recruited to the study receiving ranitidine by the oral or intravenous route.
Monoamine oxidase inhibitory activity of some Hypericum species native to South Brazil
Authors: Gnerre Carmela , von Poser Gilsane L , Ferraz Alexandre , Viana Alice , Testa Bernard , Rates Stela M K
Published: July 2003

The total methanol crude extracts and petroleum ether, chloroform, and methanol fractions obtained from Hypericum species, H. caprifoliatum, H. carinatum, H. connatum, H. cordatum, H. myrianthum, H. piriai, H. polyanthemum and H. brasiliense, all native to South Brazil, were assayed for monoamine oxidase A (MAO A) and MAO B inhibitory activity in rat brain mitochondrial preparations at concentrations ranging from 1 to 20 μg mL−1. Three benzo-pyrans, HP1 (6-isobutyryl-5,7-dimethoxy-2,2-dimethylbenzopyran), HP2 (7-hydroxy-6-iso-butyryl-5-methoxy-2,2-dimethylbenzopyran) and HP3 (5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethylbenzopyran) isolated from H. polyanthemum were also tested at maximal concentrations of 150, 150 and 75 μ, respectively. The lipophilic extracts of H. polyanthemum, H. caprifoliatum and H. piriai displayed MAO A inhibitory activity greater than 50%. Among the benzopyrans, only HP3 showed significant activity, with an IC50 value of 22 μ. The total methanol crude extracts of aerial parts from H. carinatum, H. connatum, H. cordatum, H. polyanthemum and H. piriai were evaluated for antidepressant activity in the Porsolt's forced swimming test in Wistar rats (270 mg kg−1 day−1; i.p); however, none of them showed activity.
In-vitro and in-vivo immunomodulatory effects of syringin
Authors: Cho Jae Youl , Nam Kwon Ho , Kim Ae Ra , Park Jisoo , Yoo Eun Sook , Baik Kyong Up , Yu Young Hyo , Park Myung Hwan
Published: July 2003

Syringin was found to possess immunomodulatory activity by which it inhibited the in-vitro immunohaemolysis of antibody-coated sheep erythrocytes by guinea-pig serum through suppression of C3-convertase of the classical complement. In this study, we examined its in-vitro and in-vivo activity on tumour necrosis factor (TNF)-α and nitric oxide (NO) production, CD4 + T cell and CD8+ cytotoxic T cell (CTLL-2) proliferation, and croton oil-, arachidonic acid- and fluorescein-isothiocynate (FITC)-induced mouse ear oedema model. Syringin significantly inhibited both TNF-α production from lipopolysaccharide (LPS)-stimulated RAW264.7 cells and CD8+ T cell (CTLL-2) proliferation in a dose-dependent manner, whereas neither NO production nor CD4+ T cell proliferation were blocked even by high concentrations of syringin. In the in-vivo experiments, syringin also significantly suppressed FITC-induced ear oedema in mice but not the ear oedema induced by croton or arachidonic acid. These results suggest that syringin may be implicated as an immunomodulator having an anti-allergic effect rather than an antiinflammatory effect. The anti-allergic effect of syringin seems to be due, in part, to inhibition of TNF-α production and cytotoxic T cell proliferation.
Inhibition of prostaglandin E2 production by 2′-hydroxychalcone derivatives and the mechanism of action
Authors: Kim Yong Pil , Ban Hyun Seung , Lim Soon Sung , Kimura Natsuko , Jung Sang Hoon , Ji Jun , Lee Sanghyun , Ryu Nama , Keum Sam Rok , Shin Kuk Hyun , Ohuchi Kazuo
Published: July 2003

The effects of 14 synthetic 2′-hydroxychalcone derivatives on prostaglandin E2 (PGE2) production in rat peritoneal macrophages stimulated by the protein kinase C activator, 12-O-tetradecanoylphorbol 13-acetate (TPA), were examined to clarify the structure-activity relationship. 2′,4-Dihydroxy-4′-methoxychalcone (compound 3), 2′,4-dihydroxy-6′-methoxychalcone (compound 8) and 2′-hydroxy-4′-methoxychalcone (compound 9) suppressed PGE2 production more potently than the other compounds. The IC50 (50 % Inhibitory concentration) value for compounds 3, 8 and 9 was calculated to be 3 μ. The activity of cyclooxygenase (COX)-1 was inhibited slightly by compound 9, but that of COX-2 was not inhibited. At concentrations that inhibited the production of PGE2, compound 9 had no effect on the release of radioactivity from [3H]arachidonic acid-labelled macrophages stimulated by TPA. Western-blot analysis revealed that the induction of COX-2 protein by TPA was inhibited by compound 9 in parallel with the inhibition of PGE2 production. Compounds 3 and 8 had similar effects. These findings suggest that 4′-methoxyl and 6′-methoxyl groups are required for the expression of more potent inhibitory activity against PGE2 production, and that the inhibition of PGE2 production by these 2′-hydroxychalcone derivatives is due to the inhibition of TPA-induced COX-2 protein expression.
The challenge of gene therapy and DNA delivery
Authors: Phillips Anthony J
Published: July 2003

It is 10 years since the first gene therapeutic was administered to patients. Since that time approximately 3500 patients have been treated and although some evidence of gene transfer has been seen it has generally been inadequate for a meaningful clinical response. The major challenges have been delivery of DNA to the target cells and duration of expression. A variety of gene transfer systems have been evaluated and these are summarized with their advantages and disadvantages. Encouraging data have been obtained recentlyby a number of workers and there is some optimism that the enormous potential of gene therapy will be realized in the second decade of its development.
New strategies for polymer development in pharmaceutical science — a short review
Authors: Godwin A , Bolina K , Clochard M , Dinand E , Rankin S , Simic S , Brocchini S
Published: July 2003

We are developing synthetic polymers for pharmaceutical and medical applications. These applications can be broadly grouped on how the polymer will be utilized e.g. material, excipient or molecule. Our focus is to develop polymers with more defined structures that are based on biological, physicochemical and/or materials criteria. Strategies are being developed to more efficiently optimize structure—property correlations during preclinical development. We describe two examples of our research on pharmaceutical polymer development: narrow molecular weight distribution (MWD) homopolymeric precursors which can be functionalized to give families of narrow MWD homo- and co-polymers, and hydrolytically degradable polymers.
Oral sustained delivery of theophylline from thermally reversible xyloglucan gels in rabbits
Authors: Miyazaki Shozo , Kawasaki Naoko , Endo Kumiko , Attwood David
Published: July 2003

Thermally reversible gels formed in-situ following the oral administration of dilute aqueous solutions of an enzyme-degraded xyloglucan to rabbits were evaluated as sustained-release vehicles for the delivery of theophylline. In-vitro release of theophylline from gels formed by warming xyloglucan sols (0.5, 1.0 and 1.5% w/w) to 37°C followed root-time kinetics over a period of 4 h. Gels formed after oral administration to rabbits of chilled 1.5% w/w aqueous solutions of xyloglucan containing dissolved drug showed sustained-release characteristics with a maximum plasma concentration at 4.5 h. The theophylline bioavailability from a 1.5% w/w xyloglucan gel was 1.7–2.5 times that of commercial oral sustained-release liquid dosage forms containing an identical theophylline concentration. It was concluded that dilute solutions of the enzyme-degraded xyloglucan had suitable rheological properties and in-situ gelling characteristics for use as sustained-release vehicles for oral drug delivery. The in-vivo release characteristics of theophylline in a rabbit model suggested the potential for the use of these vehicles in humans for the oral delivery of this drug.
The powder flow and compact mechanical properties of two recently developed matrix-forming polymers
Authors: Hancock Bruno C , Carlson Glenn T , Ladipo Dauda D , Langdon Beth A , Mullarney Matthew P
Published: July 2003

The powder flow and compact mechanical properties of two recently developed matrix-forming polymers were determined. The polymers are cross-linked high-amylose starch (Contramid) and poly(acrylic acid) (Carbopol EX507), and their properties were compared with those of two established matrix-forming polymers, hydroxypropyl methylcellulose (Methocel K100LV) and hydroxypropyl cellulose (Klucel EXF). The particle morphology, size distribution and true density of the four materials were quite different and they exhibited measurable performance differences with respect to powder flow, compact ductility, compact elasticity and compact tensile strength. Recommendations for formulating solid dosage forms with each of these excipients were made, based on a consideration of their physical properties and their anticipated processing performance.
Effectiveness of repeated administration of a new oral naltrexone controlled-release system on morphine analgesia
Authors: Álvarez-Fuentes J , Rojas-Corrales M O , Holgado M A , Sánchez-Lafuente C , Micó J A , Fernández-Arévalo M
Published: July 2003

Naltrexone hydrochloride, an opioid antagonist used as an adjunct to the maintenance of the opioid-free state for detoxified individuals, was introduced into the polymeric structure of Eudragit L30D, ananionic copolymer based on polymethacrylic acid and ethylacrylate. From the results of a preclinical study, this complexation technique can be considered as a useful tool in the design of oral controlled-release systems (naltrexone-Eudragit L) capable of inducing long-lasting effects in-vivo. The biopharmaceutical characterization of the naltrexone-Eudragit L complex in comparison with naltrexone hydrochloride using the mouse hot-plate model has been previously carried out. The results showed a longer effect, an enhancement of 23.47% of the area under the curve of the inhibition of analgesic activity vs time, and a delay of 51.80% in the t1/2 value induced by the complex, compared with those induced by conventional naltrexone. In this study, a regimen of chronic administration of naltrexone-Eudragit L was established. Thus, in an 8-day treatment (4 doses in alternate days) this oral controlled-release system effectively antagonized the analgesic effect of morphine for 8 h, whereas naltrexone hydrochloride has to be administered over 16 days (8 doses in alternate days) to induce the same effect. In the 16-day schedule the complex-induced antagonism lasted over 14 h after administration.
Colon-specific delivery of budesonide from microencapsulated cellulosic cores: evaluation of the efficacy against colonic inflammation in rats
Authors: Rodriguez Marta , Antúnez José Antonio , Taboada Cristina , Seijo Begoña , Torres Dolores
Published: July 2003

Budesonide (BDS) is a potent corticosteroid that has important implications in the pharmaco-therapy of inflammatory bowel disease, especially in the treatment of ulcerative colitis and Crohn's disease. BDS is available on the market in the form of enteric-coated preparations. However these products, similar to other available site-specific dosage forms, are not sufficiently selective to treat colonic inflammatory bowel disease. The objective of this study was to evaluate the efficacy of a new microparticulate system containing BDS, to treat experimentally induced colitis in rats. This microparticulate system consisted of BDS-containing hydrophobic cores, microencapsulated within an enteric polymer, which solubilizes at above pH 7, thus combining pH-sensitive and controlled-release properties. Colonic injury and inflammation were assessed by measuring colon/bodyweight ratio, myeloperoxidase (MPO) activity, and by scoring macroscopic and histological damage in colitic rats. Rats were treated orally with BDS, included in the developed system, once a day for 4 days after the induction of inflammation. A BDS suspension and BDS-containing enteric microparticles were included as control formulations in the experimental design. The administration of the new BDS delivery system significantly reduced the colon/bodyweight ratio compared with the administration of control formulations. Similarly, MPO activity and macroscopic and histological damage of the inflamed colonic segments decreased significantly when the BDS formulation was administered, compared with the results obtained after oral administration of the drug suspension. There were no significant differences, however, when the new treatment was compared with the control formulation consisting of simple enteric microparticles.
Improved activity and stability of lysozyme at the water/CH2CI2 interface: enzyme unfolding and aggregation and its prevention by polyols
Authors: Pérez Caroline , Griebenow Kai
Published: July 2003

Protein inactivation and aggregation at the water/CH2CI2 interface is one of the most detrimental events hindering the encapsulation of structurally unperturbed proteins into poly(lactide-co-glycolide) (PLG) microspheres for their clinical application as sustained release dosage forms. We have investigated the inactivation and aggregation of the model protein hen egg-white lysozyme at this interface and devised methods to prevent both events. When lysozyme was exposed to a large water/CH2CI2 interface achieved by homogenization, lysozyme aggregation occurred. Fourier-transform infrared (FTIR) spectroscopic data demonstrated that the aggregates formed contained intermolecular β-sheets. The aggregates were of a non-covalent nature because they slowly dissolved in D2O and the IR spectral bands typical for the intermolecular β-sheets disappeared at approximately 1617 and 1690 cm−1. The observed loss in specific enzyme activity of soluble lysozyme was caused by the irreversible formation of an unfolded lysozyme species, which was found to be monomeric, and was able to leave the water/CH2CI2 interface and accumulate in the aqueous phase. Polyols were, in a concentration dependent fashion, efficient in ameliorating lysozyme unfolding and aggregation. However, prevention of lysozyme aggregation and activity loss in the various samples were unrelated. Thus, polyols must work by more than one mechanism preventing the two events. For the first time, an excipient effect on the conformational stability of lysozyme has been excluded from contributing to the prevention of lysozyme unfolding and aggregation.
Iontophoretic pulsatile transdermal delivery of human parathyroid hormone (1–34)
Authors: Suzuki Yasuyuki , Iga Katsumi , Yanai Shigeo , Matsumoto Yukihiro , Kawase Masahiro , Fukuda Tunehiko , Adachi Hirotoshi , Higo Naruhito , Ogawa Yasuaki
Published: July 2003

Iontophoretic pulsatile transdermal delivery of hPTH(1–34) was examined in Sprague-Dawley (SD) rats, hairless rats and beagle dogs. Application for 60 min (200 μ 0.1 mA cm−2) showed current-responsive increases in serum hPTH(1–34) levels in all the animals. In SD rats, the area under the curves of serum hPTH(1–34) levels (AUCs) were proportional to the doses (40, 120, 200, 400 and 1000 μg) and current densities (0.05, 0.1 and 0.15 mA cm−2) applied. The absorption rates per 200-μg dose, calculated by a deconvolution method, were 6.7, 2.4 and 3.7 μg h−1 for SD rats, hairless rats and beagle dogs, respectively. These values correlated well with the ratios of the skin porosity to the dermal thickness reported for these animals, which are believed to represent the reciprocal of the electrical resistance of the aqueous channels formed by the hair follicles. From this correlation, we suggested that absorption of hPTH(1–34) occurs mainly via the hair-follicle route, and that the absorption rate in man might be intermediate between those in hairless rats and beagle dogs. Three-fold repetitions of 30 min current with various rest intervals produced current-responsive triple pulses in serum hPTH(1–34) levels in SD rats. Seven-fold repetitions of current also produced similar current-responsive pulsatile serum hPTH(1–34) levels. However, peak serum hPTH(1–34) levels tended to decrease gradually after the fourth current application, possibly due to consumption of the electrodes, suggesting that three-fold repetitions of current might be optimal. These findings suggest that this iontophoretic administration system could create a repeated-pulsatile pattern of serum hPTH(1–34) levels without the necessity for frequent injections, and may be useful for the treatment of osteoporosis with hPTH(1–34).
Pharmacokinetic-pharmacodynamic modelling of human insulin: validity of pharmacological availability as a substitute for extent of bioavailability
Authors: Miyazaki Makoto , Mukai Haruko , Iwanaga Kazunori , Morimoto Kazuhiro , Kakemi Masawo
Published: July 2003

A method for assessing the extent of bioavailability (EBA) of human insulin from pharmacological data was determined. The time course governing increases in the plasma concentration of immuno-reactive insulin (IRI), as well as its pharmacological effects (glucodynamics), was determined after the intravascular administration of varying doses of human insulin. Pharmacokinetic (PK), pharmacodynamic (PD), and link models were constructed to elucidate the quantitative relationship between plasma IRI levels and pharmacological effects. After extravascular administration of the test formulation, only the time course governing the observed pharmacological effects was determined. The pharmacological data was translated into theoretical plasma concentration data, using the PK-PD model. Following this, the area under the theoretical plasma concentration-time curve (AUC) of the test formulation was calculated. The EBA was then estimated against a reference (intravascular) formulation, using a conventional equation. Since the pharmacological effects of insulin were observed to be highly dosing-rate-dependent, the PD model used in this study was modified to apply over a wide range of infusion rates. The results of the PK-PD analysis indicate that the doses administered can be accurately predicted from pharmacological data. To validate this method, the EBAs of controlled release formulations (the Osmotic Mini Pumps) of insulin, subcutaneously administered to the rat, were estimated. The EBA values obtained (92–96%) fell within a reasonable range. The area under the effect-time curves (AUE) obtained following subcutaneous applications of the Osmotic Mini Pump were calculated in a model-independent manner, in addition to pharmacological availabilities (PA), which were estimated against the reference (intravascular) formulations. The estimated PA values varied from 312% to 78%, in accordance with the intravascular input rates of the reference formulations. This indicates that PA should not be used as a substitute for EBA, unless data involving similar intravascular dosing rates to that of the reference formulations is available.
Effect of some hexahydroimidazo[1,2-c]pyrimidines in inflammatory responses involving leucocytes and macrophages
Authors: Vidal A , Ferrándiz M L , Ubeda A , Acero-Alarcon A , Sepulveda-Arques J , Alcaraz M J
Published: July 2003

We have studied the effects of some hexahydroimidazo[1,2-c]pyrimidine derivatives (HIPs) on leucocyte functions in-vitro and we have assayed the anti-inflammatory activity of these compounds in two models of inflammation. All HIPs inhibited the human neutrophil degranulation process and superoxide generation at concentrations in the μM range. In mouse peritoneal macrophages stimulated with lipopolysaccharide, HIP-4 and HIP-5 inhibited nitrite production without affecting prostaglandin E2 (PGE2) accumulation. HIP-4 was also active in the zymosan-injected mouse air pouch model (at 100 nmol/pouch), with significant reductions in leucocyte migration and PGE2 and leukotriene B4 levels in the air pouch exudate. To confirm the anti-inflammatory effects of this compound, we tested HIP-4 orally (10–40 mg kg−1) on carrageenan mouse-paw oedema where it exerted a dose-dependent inhibition of paw swelling with significant reductions of myeloperoxidase and elastase activity and PGE2 levels in paw homogenates. This study demonstrates that some HIPs inhibit leucocyte functions and one of these derivatives (HIP-4) shows anti-inflammatory activity when administered by the oral route, which can be related to inhibition of leucocyte migration.
Role of intracellular calcium in the spermicidal action of 2‘,4’-dichlorobenzamil, a novel contact spermicide
Authors: Patni Anil K , Gupta Sunil , Sharma Ajay , Tiwary Ashok K , Garg Santosh K
Published: July 2003

The Na+-Ca2+ exchanger and Ca2+-ATPase pumps reported to be present on the sperm membrane are responsible for maintaining the intracellular Ca2+ concentration that is involved in regulation of sperm function. We have investigated the role of intracellular Ca2+ in the presence of 2′,4′-dichlorobenzamil hydrochloride (benzamil), a Na+-Ca2+ exchange inhibitor, on human sperm motility. The mechanism of the complementary spermicidal action produced by a combination of benzamil and propranolol on human spermatozoa has been investigated also. When administered alone benzamil and propranolol produced a dose- and time-dependent decrease in motility of sperm in ejaculated semen and spermatozoa separated from semen. A combination of benzamil and propranolol exhibited a complementary spermicidal action, thereby resulting in dose reduction of both drugs for obtaining total immotility within 1 min of administration. An increase in the intracellular Ca2+ level was found to contribute to the spermicidal activity. Inhibition of the Na+-Ca2+ exchange system on sperm membrane by benzamil and membrane stabilization by propranolol resulted in accumulation of Ca2+ inside the sperm cells. When the two drugs were used in combination the time required for the total loss of motility of spermatozoa was significantly reduced due to a similar mechanism of action of both drugs.
Individual and synergistic antioxidative actions of melatonin: studies with vitamin E, vitamin C, glutathione and desferrrioxamine (desferoxamine) in rat liver homogenates
Authors: Gitto Eloisa , Tan Dun-Xian , Reiter Russel J , Karbownik Malgorzata , Manchester Lucien C , Cuzzocrea Salvatore , Fulia Francesco , Barberi Ignazio
Published: July 2003

The pharmacological effects of melatonin, vitamin E, vitamin C, glutathione and desferrioxamine (desferoxamine) alone and in combination on iron-induced membrane lipid damage in rat liver homogenates were examined by estimating levels of malondialdehyde and 4-hydroxyalkenals (MDA + 4-HDA). Individually, melatonin (2.5–1600 μM), vitamin E (0.5–50 μM), glutathione (100–7000 μM) and desferrioxamine (1–8 μM) inhibited lipid peroxidation in a concentration-dependent manner. Vitamin C had both a pro-oxidative (25–2000 μM) and an antioxidative (2600–5000 μM) effect. The IC50 (concentration that reduces damage by 50%) values were 4, 10, 426, 2290 and 4325 μM for vitamin E, desferrioxamine, melatonin, glutathione and vitamin C, respectively. The synergistic actions of melatonin with vitamin C, vitamin E, and glutathione were systematically investigated. When melatonin was combined with vitamin E, glutathione, or vitamin C, the protective effects against iron-induced lipid peroxidation were dramatically enhanced. Even though melatonin was added at very low concentrations, it still showed synergistic effects with other antioxidants at certain concentrations. Furthermore, melatonin not only reversed the pro-oxidative effects of vitamin C, but its efficacy in reducing lipid peroxidation was improved when it was combined with prooxidative concentrations of vitamin C. The results provide new information in terms of the possible pharmacological use of the combination of melatonin and classical antioxidants to treat free radical-related conditions.
Responsiveness, affinity constants and receptor reserves for serotonin on aortae of aged normotensive and hypertensive rats
Authors: Doggrell Sheila A , Chen Ying-yu
Published: July 2003

We have previously shown that the potency and affinity constants (KA values) for serotonin (5-HT) are greater, and the 5-HT2A-receptor reserve is lesser, on the aorta of 6-month-old spontaneously hypertensive rats (SHRs) compared with age-matched Wistar Kyoto normotensive (WKY) rats. The present study was undertaken to investigate whether these parameters are altered on the aorta with ageing and as hypertension progresses to heart failure. The effects of phenoxybenzamine on the serotonergic responses of the aortae of 24-month-old WKY rats and SHRs were determined. On WKY rat aorta, ageing from 6 to 24 months was associated with an increase in sensitivity and affinity for serotonin, and a loss of 5-HT2A-receptor reserve. On SHR aorta, ageing from 6 to 24 months was also associated with an increase in sensitivity and affinity for serotonin, but a loss of 5-HT2A-receptor reserve. The sensitivity to serotonin was greater on the 24-month-old SHR aorta (pD2 6.53) than age-matched WKY rat aorta (pD2 5.89). On the aorta of the 24-month-old WKY rats, the KA value for serotonin was 4.5 times 10−6 M, and the receptor occupancies required for 20 and 50% maximum responses were 12 and 29%, respectively. There was a similar affinity, but greater receptor reserves, for serotonin on the aorta of age-matched SHRs. In summary, we have shown changes in sensitivity, affinity and 5-HT2A-receptor reserves for serotonin on the aorta with ageing and in hypertension/heart failure.
Synthesis of new arylaminoquinoxalines and their antimalarial activity in mice
Authors: Rangisetty J B , Gupta C N V H B , Prasad A L , Srinivas P , Sridhar N , Parimoo P , Veeranjaneyulu A
Published: July 2003

2-Arylaminoquinoxalines were prepared by the condensation of 2-chloroquinoxaline with the appropriate Mannich bases in the presence of HCl. To synthesize the Mannich bases, 4-acetamidophenol was reacted with formaldehyde and dialkylamine to yield 3-[(dialkylamino) methyl]-4-hydroxyacetanilide, followed by hydrolysis. Antimalarial activities of the new arylaminoquinoxalines were evaluated against the rodent malaria parasite Plasmodium yoelii at a dose of 75 mg kg−1. Three compounds synthesized (2-[3-[(diethylamino) methyl]-4-hydroxy-anilino]-quinoxaline dihydrochloride (2b), 2-[3-[(pyrrolidinyl) methyl]-4-hydroxyanilino]-quinoxaline dihydrochloride (2f), and 2-[3-[(piperidinyl) methyl]-4-hydroxyanilino]-quinoxaline dihydrochloride (2g)) showed moderate antimalarial activity.
Spray-dried insulin particles retain biological activity in rapid in-vitro assay
Authors: Patel Neha , Craddock Bridget L , Staniforth John N , Tobyn Michael J , Welham Melanie J
Published: July 2003

The purpose of this study was to rapidly determine, without the use of extensive animal studies, whether biological activity is retained after spray drying insulin with two excipients, lactose and xanthan gum. This was achieved by the detection of protein kinase B (PKB), which is activated by phosphorylation in response to insulin binding to cellular receptors. A myeloid cell line was cultured and stimulated with the reconstituted insulin powders. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was then utilised to allow in-vitro detection of phosphorylated PKB using an anti-phospho-PKB antibody. A single band specific to phosphorylated PKB was found on the Western blots, indicating that the active conformation of insulin was retained when spray dried in combination with lactose and with xanthan gum over the spray-drying inlet temperature range of 110–170°C. Evidence of inactivation/denaturation was observed when insulin was spray dried at an inlet temperature of 200°C. The assay may be of use as a more rapid and economic means to screen insulin formulations for inhalation and other purposes as opposed to conventional monitoring of blood glucose levels in animals.
Rectal antinociceptive properties of alverine citrate are linked to antagonism at the 5-HT1A receptor subtype
Authors: Coelho Anne-Marie , Jacob Luc , Fioramonti Jean , Bueno Lionel
Published: July 2003

Serotonin (5-HT) is considered as a major mediator causing hyperalgesia and is involved in inflammatory reactions and irritable bowel syndrome. Alverine citrate may possess visceral antinociceptive properties in a rat model of rectal distension-induced abdominal contractions. This study was designed to evaluate the pharmacological properties of alverine citrate in a rat model of rectal hyperalgesia induced by 5-HTP (5-HT precursor) and by a selective 5-HT1A agonist (8-OH-DPAT) and to compare this activity with a reference 5-HT1A antagonist (WAY 100635). At 4 h after their administration, 5-HTP and 8-OH-DPAT increased the number of abdominal contractions in response to rectal distension at the lowest volume of distension (0.4 mL). When injected intraperitoneally before 8-OH-DPAT and 5-HTP, WAY 100635 (1 mg kg−1) blocked their nociceptive effect, but also reduced the response to the highest volume of distension (1.6 mL). Similarly, when injected intraperitoneally, alverine citrate (20 mg kg−1) suppressed the effect of 5-HTP, but not that of 8-OH-DPAT. However, when injected intracerebroventricularly (75 μg/rat) alverine citrate reduced 8-OH-DPAT-induced enhancement of rectal distension-induced abdominal contractions. In-vitro binding studies revealed that alverine citrate had a high affinity for 5-HT1A receptors and a weak affinity for 5-HT3 and 5-HT4 subtypes. These results suggest that 5-HTP-induced rectal hypersensitivity involves 5-TH1A receptors and that alverine citrate acts as a selective antagonist at the 5-HT1A receptor subtype to block both 5-HTP and 8-OH-DPAT-induced rectal hypersensitivity.
Human lactoferrin: a novel therapeutic with broad spectrum potential
Authors: Weinberg Eugene D
Published: July 2003

Lactoferrin (Lf), a natural defence iron-binding protein, has been found to possess antibacterial, antimycotic, antiviral, antineoplastic and anti-inflammatory activity. The protein is present in exocrine secretions that are commonly exposed to normal flora: milk, tears, nasal exudate, saliva, bronchial mucus, gastrointestinal fluids, cervico—vaginal mucus and seminal fluid. Additionally, Lf is a major constituent of the secondary specific granules of circulating polymorphonuclear neutrophils (PMNs). The apoprotein is released on degranulation of the PMNs in septic areas. A principal function of Lf is that of scavenging free iron in fluids and inflamed areas so as to suppress free radical-mediated damage and decrease the availability of the metal to invading microbial and neoplastic cells. Mechanisms of action of Lf in addition to iron deprivation are also described. Administration of exogenous human or bovine Lf to hosts with various infected or inflamed sites has resulted in some prophylactic or therapeutic effects. However, an adverse response to the protein might occur if it were to stimulate antibody production or if it were to provide iron to the invading pathogen. The recombinant form of human Lf has become available and development of the product for use in a wide range of medical conditions can now be anticipated.
Skin hydration and possible shunt route penetration in controlled estradiol delivery from ultradeformable and standard liposomes
Authors: El Maghraby Gamal M M , Williams Adrian C , Barry Brian W
Published: July 2003

Human skin delivery of estradiol from ultradeformable and traditional liposomes was explored, comparing occlusive and open application, with the aim of examining the role of skin hydration. Partially hydrated epidermis was used for open hydration, but fully hydrated membranes were used for occluded studies. In addition, we developed a novel technique to investigate the role of shunt route penetration in skin delivery of liposomal estradiol. This compared delivery through epidermis with that through a stratum corneum (SC)/epidermis sandwich from the same skin with the additional SC forming the top layer of the sandwich. This design was based on the fact that orifices of shunts only occupy 0.1% of skin surface area and thus for SC/epidermis sandwiches there will be a negligible chance for shunts to superimpose. The top SC thus blocks most shunts available on the bottom membrane. If shunts play a major role then the delivery through sandwiches should be much reduced compared with that through epidermis, taking into consideration the expected reduction owing to increased membrane thickness. After open application, both ultradeformable and traditional liposomes improved estradiol skin delivery, with the ultradeformable liposomes being superior. Occlusion reduced the delivering efficiency of both vesicle types, supporting the theory that a hydration gradient provides the driving force. Shunt route penetration was found to play only a very minor role in liposomal delivery. In conclusion, full hydration of skin reduces estradiol delivery from liposomes and the shunt route is not the main pathway for this delivery.
Effect of herbal teas on hepatic drug metabolizing enzymes in rats
Authors: Maliakal Pius P , Wanwimolruk Sompon
Published: July 2003

We have investigated the effect of herbal teas (peppermint, chamomile and dandelion) on the activity of hepatic phase I and phase II metabolizing enzymes using rat liver microsomes. Female Wistar rats were divided into six groups (n = 5 each). Three groups had free access to a tea solution (2 %) while the control group had water. Two groups received either green tea extract (0.1 %) or aqueous caffeine solution (0.0625 %). After four weeks of pretreatment, different cytochrome P450 (CYP) isoforms and phase II enzyme activities were determined by incubation of liver microsomes or cytosol with appropriate substrates. Activity of CYP1A2 in the liver microsomes of rats receiving dandelion, peppermint or chamomile tea was significantly decreased (P < 0.05) to 15 %, 24 % and 39 % of the control value, respectively. CYP1A2 activity was significantly increased by pretreatment with caffeine solution. No alterations were observed in the activities of CYP2D and CYP3A in any group of the pretreated rats. Activity of CYP2E in rats receiving dandelion or peppermint tea was significantly lower than in the control group, 48 % and 60 % of the control, respectively. There was a dramatic increase (244 % of control) in the activity of phase II detoxifying enzyme UDP-glucuronosyl transferase in the dandelion tea-pretreated group. There was no change in the activity of glutathione-S-transferase. The results suggested that, like green and black teas, certain herbal teas can cause modulation of phase I and phase II drug metabolizing enzymes.
Pharmacokinetic behaviour of cisplatin in peritoneal fluid after intraperitoneal administration of cisplatin-loaded microspheres
Authors: Tamura Takshi , Imai Jun , Matsukawa Yasuhisa , Horikiri Yuji , Suzuki Takehiko , Yoshino Hiroyuki , Ike Osamu
Published: July 2003

The objective of this study was to establish a pharmacokinetic model for the estimation of unchanged cis-dichlorodiammine-platinum (II) (CDDP) concentration in peritoneal fluid after intraperitoneal administration of cisplatin-loaded microspheres (CDDP-MS) and to elucidate the accuracy of this model by comparisons between actual and simulated values after intraperitoneal administration of CDDP-MS. We developed a method enabling the precise and quick assessment of the drug concentration in the peritoneal cavity. The pharmacokinetic parameters obtained after intravenous bolus injection at a dose of 2 mg kg−1 were total body clearance (1026 mL h−1 kg−1), elimination rate constant (3.24 h−1) and distribution volume of systemic circulation (316.7 mL kg−1). After an intraperitoneal bolus injection at a dose of 5 mg kg−1, the absorption rate constant from the peritoneal cavity (3.64 h−1) and the distribution volume of the peritoneal cavity (13.5 mL kg−1) were determined. The protein-binding rate constant in ascites was 0.58 h−1. Using these pharmacokinetic parameters, we established a pharmacokinetic model consisting of two compartments. Administration of CDDP-MS at a dose of 10 mg kg−1, which released CDDP over 7 days in-vitro, yielded sustained concentrations of unchanged CDDP (1–2 mg mL−1) in the peritoneal cavity that persisted for 7 days, and that were predictable by applying the in-vitro dissolution profile to the pharmacokinetic model. The findings obtained from this study are useful for understanding the basic pharmacokinetic characteristics of unchanged CDDP in the peritoneal cavity and may also be important in the development of optimized CDDP-MS formulations.
Effect of instillation method on the absorption of phenolsulphonphthalein as a model drug from the liver and small intestinal serosal surface in rats
Authors: Nishida Koyo , Yoshida Yayoi , Mukai Takahiro , Kawakami Shigeru , Sakaeda Toshiyuki , Nakashima Mikiro , Sasaki Hitoshi , Nakamura Junzo
Published: July 2003

We have examined the effect of the instillation method on the absorption of a drug from the liver and the small intestinal serosal surface in rats. We performed continuous microinstillation via an infusion pump and bolus instillation via a syringe, using phenolsulphonphthalein (phenol red) as the model drug. After continuous microinstillation of phenolsulphonphthalein 2.35 mg in 235 μL for 5 min on the liver and small intestinal serosal surface in rats, the AUC (area under the curve) of the plasma concentration profile up to 60 min was significantly higher compared with bolus instillation. A similar trend was observed after continuous microinstillation of phenolsulphonphthalein 2.35 mg in 117.5 μL for 2.5 min. The calculated absorption rate constants (Ka) after continuous microinstillation of phenolsulphonphthalein based on a two-compartment model with first-order absorption were higher than those after bolus instillation on the liver and small intestinal serosal surface at either instillation concentration. Moreover, Ka was increased after continuous microinstillation of 2.35 mg in 117.5 μL at either instillation site. Instillation of phenolsulphonphthalein on the liver surface resulted in a 1.2- to 2.3-fold higher Ka compared with the small intestinal serosal surface. This tendency was marked after continuous microinstillation of 2.35 mg in 117.5 μL. In conclusion, absorption could be enhanced by instilling a small amount of drug solution on the liver surface gradually and continuously, suggesting a promising approach for instillation site-selective drug delivery in the peritoneal cavity.
In-vitro activity of S. lavandulaefolia (Spanish sage) relevant to treatment of Alzheimer's disease
Authors: Perry Nicolette S L , Houghton Peter J , Sampson Julia , Theobald Anthony E , Hart Stephen , Lis-Balchin Maria , Hoult J Robin S , Evans Patricia , Jenner Peter , Milligan Stuart , Perry Elaine K
Published: July 2003

Salvia lavandulaefolia Vahl. (Spanish sage) essential oil and individual monoterpenoid constituents have been shown to inhibit the enzyme acetylcholinesterase in-vitro and in-vivo. This activity is relevant to the treatment of Alzheimer's disease, since anticholinesterase drugs are currently the only drugs available to treat Alzheimer's disease. Other activities relevant to Alzheimer's disease include antioxidant, anti-inflammatory and estrogenic effects. Results of in-vitro tests for these activities are reported here for S. lavandulaefolia extracts, the essential oil and its major constituents. Antioxidant activity (inhibition of bovine brain liposome peroxidation) was found in the EtOH extract of the dried herb (5 mg mL−1) and the monoterpenoids (0.1 M) α- and β-pinene and 1,8-cineole. Thujone and geraniol had lower antioxidant effects, while camphor had no antioxidant effects. Possible anti-inflammatory activity (eicosanoid inhibition in rat leucocytes) was found in the EtOH extract (50 μg mL−1) and was shown by the monoterpenoids α-pinene and geraniol (0.2 mM), but not 1,8-cineole, thujone or camphor. Possible estrogenic activity (via induction of β-galactosidase activity in yeast cells) was found in the essential oil (0.01 mg mL−1) and the monoterpenoid geraniol (0.1–2 mM). 1,8-Cineole, α- and β-pinene and thujone did not exhibit estrogenic activity in this analysis. These results demonstrate that S. lavandulaefolia, its essential oil and some chemical constituents have properties relevant to the treatment of Alzheimer's disease and provide further data supporting the value of carrying out clinical studies in patients with Alzheimer's disease using this plant species.