Dextran-based hydrogel microspheres obtained in w/o emulsion: preparation, characterisation and in vivo studies.

The cross-linking reaction in w/o emulsions of dextran (DEX) functionalised with methacrylic groups, having or not acid residues in side chain, can be used to easily prepare polysaccharide hydrogel microspheres with properties suitable for drug delivery applications. The formation of a chemical network within the obtained particles was evaluated with FT-IR spectroscopy, whereas morphology and dimensions of the microspheres were investigated with optical and scanning electron microscopy. At the same time, swelling measurements were carried out on freeze-dried particles in different aqueous media simulating biological fluids. Preliminary release experiments performed with ibuprofen, betamethasone and vitamin B12 chosen as model drugs, showed that these microspheres could be suitable as modified drug delivery systems in oral formulations. Finally, in vivo writhing experiments were carried out in mice in order to verify the antinociceptive activity of betamethasone loaded into the new polysaccharide hydrogel microspheres.

Physical carboxymethylscleroglucan/calcium ion hydrogels as modified drug delivery systems in topical formulations.

A carboxymethyl derivative of scleroglucan (Scl-CM) with a 65+/-5% carboxylic group degree of derivatization (DD) was recently synthesized and characterized. Aqueous solutions of the polymer underwent to a sharp transition toward a gel like behaviour in the presence of divalent ions such as Ca(+2). Physical hydrogels with different Scl-CM/Ca(+2) ratios were prepared and characterized for their rheological behaviour. Their potential as drug delivery systems was also evaluated. To this end three non steroidal anti-inflammatory drugs (NSAIDs) were loaded into the hydrogels obtained with 2% w/v solution of Scl-CM and 0.05 and 0.1 M CaCl(2). The release rate of the drugs was critically related to the salt concentration. By an appropriate combination of the hydrogels prepared using different amounts of salt, it was possible to obtain a system able to release diclofenac with zero-order kinetics. Primary skin irritation tests showed a good biocompatibility of the new polymer, as well as of its hydrogels. These results suggest a potential of the new hydrogels for the development of modified delivery systems in topical formulations.

Inhibition of intestinal motility and secretion by extracts of Epilobium spp. in mice.

Ethanol extracts of the fresh aerial parts of various Epilobium species were tested to elucidate the mechanism of their gastrointestinal activity in animals. The methods of charcoal meal, castor oil-induced diarrhoea, and enteropooling assay were used to evaluate their effect on mouse gut at various dose levels. The extracts were found to have a significant activity in all models. Moreover, the extracts resulted to possess very little toxicity. Thus, it can be concluded that Epilobium possesses anti-diarrhoeal, anti-motility, and anti-secretory activities and can prove beneficial in the treatment of gastrointestinal disorders.

Effect of a standardized extract of red orange juice on proliferation of human prostate cells in vitro.

A standardized extract of red orange juice (ROE) was shown to inhibit proliferation of fibroblast and epithelial prostate cells. These data suggest that the antiproliferative properties of ROE cannot be ascribed to cytotoxic effect and highlight its potential usefulness in the management of benign prostatic hyperplasia.

Biological evaluation of a polyvinyl siloxane impression material.

OBJECTIVES: The aim of this study was to determine the irritant properties of a new polyvinyl siloxane impression material (Ghenesil, Lascod-Italy) after single application to intact skin of the rabbit. METHODS: The material was evaluated for primary skin irritation according to the UNI EN ISO 10993-10:1996 using three healthy male New Zealand White rabbits. The back of the animals was clipped free of fur and divided into four sites with the same area 24 h before application of the sample. The material was applied to only two sites; the other two were used as controls. All the sites were covered by gauze and the back of the rabbit was wrapped with a non-occlusive bandage. After 4 h, the bandage and the test material were removed; 1h later the sites were examined for skin irritation and the observation was repeated after 24, 48 and 72 h. The Score of Primary Irritation (SPI) was calculated for each animal and the Primary Irritation Index (PII) was calculated as the arithmetical mean of SPI values. RESULTS: The PII of the test material resulted 0.06. SIGNIFICANCE: Based on present results, it can be concluded that the primary skin irritation of the polyvinyl siloxane impression material tested can be considered negligible.

Interaction of melatonin with model membranes and possible implications in its photoprotective activity.

It is well known that administration of antioxidants represents a successful strategy for preventing the occurrence and for reducing the severity of UV-mediated oxidative damage. Melatonin was recently shown to be an efficacious photoprotective agent. The aim of the present study was to better investigate the interaction of melatonin with model membranes and the possible implications in its photoprotective activity. The antioxidant activity of melatonin was tested in two 'in vitro' experimental models: (a) UV radiation-induced peroxidation in phosphatidylcholine multilamellar vesicles (MLVs); (b) scavenging activity against nitric oxide (NO). Furthermore, we investigated the melatonin/biomembrane interaction by differential scanning calorimetry (DSC) on dimyristoylphosphatidylcholine (DMPC) MLVs and unilamellar vesicles (LUVs). The findings of in vitro antioxidant tests suggest that the photoprotective effect of melatonin should be due, partially at least, to the drug scavenging activity against aqueous and lipophilic free radicals, including NO; besides, melatonin might provide its protective effect against UV radiation-induced damage also by acting as a UV-absorbing screen. The results of DSC experiments have evidenced a good capability of melatonin to interact with DMPC bilayers, causing a significant fluidifying effect; however, the transfer of melatonin in the LUVs is faster than that observed for MLVs, even if both values tend to the maximum values reachable. Our present data allow us to emphasize two points: (1) the fluidifying effect induced by melatonin on lipidic bilayers might act as a cooperative mechanism in its protective effect against peroxidative membrane damage; (2) melatonin appears able to cross biomembranes, so that it could protect intracellular components against peroxidative insult.

'In vitro' antioxidant and photoprotective properties and interaction with model membranes of three new quercetin esters.

Quercetin is well known to possess the strongest protective effect against UV light-induced lipoperoxidation. However, the absolute water insolubility of quercetin is a key step that may limit its bioavailability and, thus, its 'in vivo' employment as a photoprotective agent. The aim of the present paper was to evaluate 'in vitro' the antioxidant and photoprotective properties and the interaction with model membranes of three new semisynthetic quercetin derivatives, quercetin-3-O-acetate (Q-ac), quercetin-3-O-propionate (Q-pr) and quercetin-3-O-palmitate (Q-pal), obtained by esterification of the C-3 OH function with an aliphatic side-chain of different length. The antioxidant activity of quercetin and of its three esters was assessed in two 'in vitro' experimental models: (a) the bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical; (b) UV radiation-induced peroxidation in multilamellar vesicles (MLVs). Differential scanning calorimetry on dimyristoylphosphatidylcholine MLVs and unilamellar vesicles was employed to investigate the interaction of the drugs tested with model membranes. Finally, the stability following UV light exposure and the lipophilicity and water solubility of quercetin and its three esters were examined. The findings obtained demonstrated that the esterification with an opportune aliphatic side chain of the OH function located at the C-3 position allows the production of new quercetin derivatives, which may be good candidates as photoprotective agents. In particular, one could speculate that the esterification with a short side-chain (such as in Q-ac and Q-prop) provides the suitable chemico-physical features not only to maintain the antioxidant and photoprotective effectiveness of the parent drug, but also to be able to migrate through the aqueous environment and to interact with and cross phospholipid membranes.

Recent studies on lonidamine, the lead compound of the antispermatogenic indazol-carboxylic acids.

Lonidamine (LND) or [1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid] is an anticancer and an antispermatogenic drug whose mechanism of action is still incompletely understood. LND is effective against a number of tumors, including head, neck and breast cancers, probably because of the inhibition of mitochondrial electron transport and the enzyme hexokinase and to the induction of apoptosis. Instead, the antispermatogenic activity of LND appeared to be related not only to its energolytic activity but also to other effects activities such as the inhibition of specific chloride channels in the epididymis and the disruption of the inter-Sertoli-germ cell junctions, leading to premature release of germ cells. In addition, we recently reported that, in the rat, LND at the dose of 100 mg/Kg b.w. p.o., a fully active but well tolerated dose, caused specific changes of the testicular and epididymal macroglobulins (alpha(2)-macroglobulin, alpha(1) inhibitor-3 and alpha(1)-macroglobulin). Further studies are needed to elucidate the mechanism of action of LND, the lead compound of an interesting class of antispermatogenic drugs based on the core structure of 1-(2,4-dichlorobenzyl)-indazole-3-carboxylic acid.

Indazole carboxylic acids in male contraception.

Two new chemical entities, 1-(2,4-dichlorobenzyl)-indazole-3-carbohydrazide and 1-(2,4-dichlorobenzyl)-indazole-3-acrylic acid, were synthesized based on the core structure of lonidamine (1-(2,4-dichlorobenzyl)-indazole-3-carboxylic acid). These compounds apparently exert their effects in the testis by perturbing the Sertoli-germ cell adherens junctions causing germ cell loss from the seminiferous epithelium. Recently completed studies in the rat have demonstrated the efficacy, reversibility, and potential use of these two compounds as oral contraceptives for men. Neither compound affected the hypothalamus-pituitary-testicular axis, and both compounds were neither hepatotoxic nor nephrotoxic. These results suggest that these two compounds are safe for further development.

Extracts of various species of Epilobium inhibit proliferation of human prostate cells.

This study examined whether various species of Epilobium, a phytotherapeutic agent used in folk medicine as a treatment for benign prostatic hyperplasia, may have an antiproliferative effect in PZ-HPV-7 human prostatic epithelial cells in-vitro. The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) test, [methyl-(3)H]thymidine incorporation into DNA and flow cytometry analysis were used to evaluate cell proliferation. Ethanolic extracts of E. spicatum, E. rosmarinifolium and E. tetragonum inhibited DNA synthesis in PZ-HPV-7 cells. While at high concentrations all extracts were cytotoxic, DNA synthesis was also decreased at levels that caused no or little cytotoxicity. Treatment of cells with Epilobium extracts did not result in a formation of DNA fragments (evaluated by the TUNEL assay) or chromatin condensation (assessed by Hoechst staining). Flow cytometry analysis indicated that Epilobium extracts inhibit the progression of the cell cycle from the G(0)/G(1) phase. These results suggest that extracts of Epilobium inhibit proliferation of human PZ-HPV-7 cells in-vitro by affecting progression of the cell cycle. This study provides some initial biological plausibility for the use of Epilobium extracts in benign prostatic hyperplasia.

Novel pH-sensitive physical hydrogels of carboxymethyl scleroglucan.

A carboxymethyl derivative of scleroglucan (Scl-CM) with derivatization degree 300 ± 10 was synthesized and characterized by Fourier transform infrared spectroscopy, potentiometer titration, mucus adhesion studies, and rheological measurements. Rheological measurements showed the ability of the polymer to undergo sol-gel transitions even in the absence of salts. Swelling experiments, performed on freeze-dried samples in different media, showed good affinity of these hydrogels toward the aqueous media and a pH-sensitive behavior. Four nonsteroidal anti-inflammatory drugs (NSAIDs) were loaded into the physical hydrogels obtained from 2.0% (w/v) solutions of the polymer. The results of the release studies carried out in conditions simulating the gastrointestinal tract showed that the new hydrogels could be suggested for the modified oral delivery of NSAIDs, particularly damaging for the gastric mucosa. In vivo studies proved the biocompatibility of the matrix and the absence of any gastric damage for administration of ulcerogenic doses of diclofenac loaded into the hydrogel (DIC/Scl-CM-300). Moreover, DIC/Scl-CM-300 was found to be effective in peripheral analgesia.

Antiproliferative and cytotoxic activity of extracts from Cistus incanus L. and Cistus monspeliensis L. on human prostate cell lines.

Benign prostatic hypertrophy (BPH) is a common condition in elderly men that impairs quality of life and leads to a number of medical complications. The use of phytotherapeutic compounds in patients with relatively moderate BPH symptoms has been growing steadily. In the present study, acute toxicity of lyophilised aqueous extracts of Cistus incanus L. and Cistus monspeliensis L., collected in Sicily, was evaluated on the shrimp (Artemia salina L.) lethality assay, an alternative test to determine the toxicity of natural products. The cytotoxic and growth inhibitory effects were studied on normal human prostate cells (PZ-HPV-7 and PNT1A) and on a lung fibroblast cell line (V79-4). Cell proliferation was evaluated by MTT and SRB assays. Cytotoxicity was measured using the Trypan blue exclusion assay. Cistus extract treatment on prostate cell lines resulted in an almost identical growth inhibitory response and in a significant decrease in an cell viability. These findings indicate the biologically relevant effect of polyphenolic compounds present in Cistus extracts, and suggest that these substances may prove beneficial in BPH treatment.

pH-sensitive hydrogels of dextran: synthesis, characterization and in vivo studies.

pH-Sensitive hydrogels of dextran were synthesized by photochemical cross-linking reaction of methacrylate dextran (DEX-MA) at different derivatization degree, functionalized with acidic residues through reaction with phthalic anhydride. The hydrogels were characterized by FT-IR spectra, swelling measurements, experiments of chemical and enzymatic hydrolyses. The swelling data agreed with the formation of networks having pH-sensitive behaviour. This property was confirmed by the morphological examination performed by scanning electron microscopy on samples maintained in media at different pH. (S)-4-Isobutyl-2-phenylpropionic acid (ibuprofen) was loaded into the polymeric matrices. The analysis of the release profiles of the drug from the three networks showed that all the matrices were able to retain ibuprofen during the transit through the stomach, releasing it in a sustained way in the intestinal tract at a rate strictly dependent on the derivatization degree in methacrylic groups. In vivo studies verified the biocompatibility of the materials. Moreover, when the matrix loaded with ibuprofen was administered to rats, it was able to protect them from the ulcerogenic effects of the drug.

Studies on antidiarrhoeal activity of an extract of wine from Jacquez grapes in mice.

The present study was designed to verify the antidiarrhoeal effects of a lyophilized extract of wine from Jacquez grapes (Ord. Rhamnales; Fam. Vitaceae; Sp. Vitis aestivalis M.-cinerea E. x Vitis vinifera L.), studying its influence on castor oil-induced diarrhoea and enteropooling, and on gastrointestinal transit (measured by a charcoal marker) in mice. The pre-treatment of the animals with the JWE (Jacquez wine extract) produced a significant inhibition against castor oil induced-diarrhoea and intestinal fluid accumulation; furthermore the extract significantly decreased the propulsive movement of the charcoal meal. These findings suggest a potential beneficial use of the JWE in the treatment of diarrhoeal diseases.

Characterization of the effect of Epilobium extracts on human cell proliferation.

We have previously shown that extracts of different Epilobium species, a phytotherapeutic agent used in folk medicine as a treatment for benign prostatic hyperplasia, inhibit proliferation of human prostate cells. The selectivity of this effect was evaluated in four different human cell lines (PZ-HPV-7, normal prostate cells; LNCaP, transformed prostate cells; HMEC, mammary cells, and 1321N1, astrocytoma cells). Different extracts of Epilobium species (E. rosmarinifolium, E. spicatum, and E. tetragonum) had similar growth-inhibitory effects in all cell lines tested, indicating a lack of specificity for prostate cells. Inhibition of DNA synthesis was mostly due to the nonpolar fraction of the extracts which is expected to contain flavonoids and sterols. Polar fractions were devoid of activity with the exception of that from E. rosmarinifolium. This species is the most potent in the antiproliferative effect and contains the highest concentration of oenothein B, a hydrolyzable ellagitannin. Oenothein B inhibited DNA synthesis in all four cell lines tested. Extracts of E. angustifolium (the Linné denomination of E. spicatum) and of E. spicatum from different sources were compared for their ability to inhibit DNA synthesis and for their oenothein B content. The E. angustifolium extract contained an amount of oenothein B 40-fold higher than the other extract of the same species and was ten times more potent in inhibiting DNA synthesis in a human prostate cell line. These results indicate that Epilobium extracts inhibit proliferation of prostate cells in a nonspecific manner. Oenothein B may play a role in this effect, but other active compounds are also present. The difference observed between extracts from the same species underscores the importance of determination and standardization of active ingredients in phytotherapeutic agents.