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PubMed2000

Studies on poly(propylene fumarate-co-ethylene glycol) based bone cement.

Poly(propylene fumarate-co-ethylene glycol) random (PPF-1) and block (PPF-2) copolymer oligomers were prepared. Comparing the setting characteristics of PPF-1 and PPF-2 with comonomer n-vinyl pyrrolidone (n-VP) and swelling characteristics of cured PPF-1 and PPF-2, lower setting temperature and setting time was observed with the former leading to higher swelling coefficient and lower cross link density in the cured PPF-1. Due to the high swelling coefficient and low setting exothermic temperature associated with PPF-1, the bone cement was prepared from PPF-1, n-VP and hydroxyapatite (HAP). The in vitro degradation studies reveal lesser weight loss and deformation of PPF-1/n-VP/HAP based cured resin in Ringer's solution and phosphate buffered saline in comparison with that of PPF-1/n-VP cured resin. Though the bone cement composite has adequate mechanical properties with HAP, the compressive strength and modulus of the composite aged in Ringer's solution and PBS reduced appreciably which is due to extensive hydration and plasticization by the PEG unit. However, the bone-binding and bond strength of the bone cement determined as the load for separation of bones was found to be similar to that of fast setting calcium phosphate-atelocollagen (5%) bone cement. The bone cement PPF-1/n-VP/HAP could be used as scaffold for correcting the bone defects.

Biocompatible Materials↗
PubMed2000

Antitumor activity of tumor necrosis factor-alpha conjugated with polyvinylpyrrolidone on solid tumors in mice.

We attempted the development of a novel polymer conjugation to further improve the therapeutic potency of antitumor cytokines compared with PEGylation for clinical application. Compared with native tumor necrosis factor (TNF)-alpha in vitro, specific bioactivities of polyvinyl-pyrrolidone (PVP)-modified TNF-alphas (PVP-TNF-alphas) were decreased by increasing the degree of PVP attachment. PVP-TNF-alpha fraction 3, Mr 101,000, had the most effective antitumor activity of the various PVP-TNF-alphas in vivo. PVP-TNF-alpha fraction 3 had >200-fold higher antitumor effect than native TNF-alpha, and the antitumor activity of PVP-TNF-alpha fraction 3 was >2-fold higher than that of MPEG-TNF-alpha (Mr 108,000), which had the highest antitumor activity among the polyethylene glycol (PEG)-conjugated TNF-alphas. Additionally, a high dose of native TNF-alpha induced toxic side effects such as body weight reduction, piloerection. and tissue inflammation, whereas no side effects were observed after i.v. administration of PVP-TNF-alpha fraction 3. The plasma half-life of PVP-TNF-alpha fraction 3 (360 min) was about 80- and 3-fold longer than those of native TNF-alpha (4.6 mm) and MPEG-TNF-alpha (122 min), respectively. The mechanism of increased antitumor effect in vivo caused the prolongation of plasma half-life and increase in stability. These results suggested that PVP is a useful polymeric modifier for bioconjugation of TNF-alpha to increase its antitumor potency, and multifunctionally bioconjugated TNF-alpha may be a potentiated antitumor agent for clinical use.

Animals↗
PubMedDate not supplied

Organic solvents for pharmaceutical parenterals and embolic liquids: a review of toxicity data.

Non-aqueous solvents have long been used in subcutaneous or intramuscular pharmaceutical formulations to dissolve water-insoluble drugs. In recent years, the need for these vehicles was increased since the drug discovery process has yielded many poorly water-soluble drugs. Besides, preparations containing embolic materials dissolved in undiluted non-aqueous water-miscible solvents have been proposed for the intravascular treatment of aneurysms, arteriovenous malformations, or tumors. These organic solvents, regarded as chemically and biologically inert, may show pharmacological and toxicological effects. Therefore, knowledge of tolerance and activity of non-aqueous solvents is essential before they can be administered, especially when given undiluted. This paper focuses on thirteen organic solvents reported as possible vehicles for injectable products and details toxicological data when they have been administered intravascularly. These solvents can be subdivided into three groups according to their description in the literature either for intravenous pharmaceutical parenterals or for intravascular embolic liquids: well-documented organic solvents (propylene glycol, polyethylene glycols, ethanol), solvents described in specific applications (dimethyl sulfoxide, N-methyl-2-pyrrolidone, glycofurol, Solketal, glycerol formal, acetone), and solvents not reported in intravascular applications but potentially useful (tetrahydrofurfuryl alcohol, diglyme, dimethyl isosorbide, ethyl lactate). This review of the literature shows that toxicity data on intravascular organic solvents are insufficient because they concern solvents diluted with water and because of the lack of comparative evaluation using the same methodologies.

Animals↗
PubMedDate not supplied

Comparative hemolytic activity of undiluted organic water-miscible solvents for intravenous and intra-arterial injection.

In humans, nonaqueous solvents are administered intravascularly in two kinds of situations. They have been used in subcutaneous or intramuscular pharmaceutical formulations to dissolve water-insoluble drugs. The need for these vehicles had increased in recent years, since the drug development process has yielded many poorly water-soluble drugs. The use of water-miscible nonaqueous solvents in therefore one of the approaches for administering these products as reference solutions useful in formulation bioequivalence studies. The intravascular use of organic solvents has also gained importance owing to a new approach for the treatment of cerebral malformations using precipitating polymers dissolved in water-miscible organic solvents. At present, the solvent most commonly used for the liquid embolics to solubilize the polymers is dimethyl sulfoxide, which exhibits some local and hemodynamic toxicities. In order to find new, less toxic vehicles for pharmaceutical formulations for the intravenous and intra-arterial routes and for embolic materials, 13 water-miscible organic solvents currently used (diluted with water) for pharmaceutical applications, were evaluated in this study. Their hemolytic activity and the morphological changes induced when mixed with blood (1:99, 5:95, 10:90 solvent:blood) were estimated in vitro. From these data, the selected organic solvents could be subdivided into four groups depending on their hemolytic activity: very highly hemolytic solvents (ethyl lactate, dimethyl sulfoxide), highly hemolytic solvents (polyethylene glycol 200, acetone), moderately hemolytic solvents (tetrahydrofurfuryl alcohol, N-methyl-2-pyrrolidone, glycerol formal, ethanol, Solketal, glycofurol) and solvents with low hemolytic activity (propylene glycol, dimethyl isosorbide, diglyme).

Erythrocytes↗
PubMed2000

A method for large-scale multiplication of Curculigo orchioides through bulbil formation from leaf explant in shake flask culture.

An efficient method has been developed for large-scale multiplication of Curculigo orchioides (Hypoxidaceae), an endangered medicinal plant, through direct bulbil formation from leaf explants in shake flask cultures. Leaf-segments (7 x 10 mm) were cultured in B5 liquid medium containing KNO3 (200 mgNL-1), (NH4)2SO4 (50 mgNL-1), benzyl adenosine (2.2 microM), adenine (0.11 mM), indole butyric acid (1.0 microM) and polyvinyl pyrrolidone (250 mgL-1). About 95% of explants produced maximum number of bulbils (546/flask at 6 weeks growth) in the medium. Shake flask cultures yielded 2737 bulbils/L medium whereas static cultures yielded 624 bulbils/L medium. Germination of bulbils was maximum (90.62%) on agar-gelled B5 medium containing benzyl adenosine (2.2 microM) and gibberellic acid (3.5 microM). Plantlets developed in vitro were successfully transferred to soil with a high rate of survivability (90%) and were comparable to natural population in growth and vigour.

Botany↗
PubMed1975

Semiquantitative test for iodine vapor above "complexed" iodine solutions.

A test to determine the extent to which free iodine exists in the vapor phase above the surface of "complexed iodine" solutions is described. The procedure is based on the qualitative starch-iodine test. The results can be related to the degree of complexation occurring between the polymer used in the preparation and iodine. Four products were tested: nonylphenoxypoly ethanol-iodine complex; polyvinyl pyrrolidine-iodine complex; popoxamer-iodine complex; and nonylphenoxypoly ethanol and polyvinyl pyrrolidone iodine complex. Free iodine in the vapor phase of the first product was detected in 90 minutes; the time for the other three was five days. For the tincture of iodine control, the time was 30 minutes.

Gases↗
PubMed2001

Control and stability of drug release from diffusion pellets coated with the aqueous quaternary polymethacrylate dispersion Eudragit RS 30 D.

The addition within compatibility limits of the pore formers hydroxypropyl methylcellulose (HPMC) and hydroxy ethylcellulose (HEC) to coatings of the quaternary polymethacrylate dispersion Eudragit RS 30 D enables drug release to be controlled without problems. 20 and 15%, respectively, of these pore formers are suitable for release within 8 h of theophylline from pellets with a coating thickness of about 30 microns. A 10% addition of plasticizer, water soluble triethyl citrate (TEC) or water insoluble dibutyl phthalate (DBP), lowers the minimum film forming temperature (MFT) from 48 to 17 and 26 degrees C, respectively. The MFT is scarcely influenced by the pore formers. However, the plasticizers may modify the effect of the pore formers: HPMC is more effective in the presence of DBP. In spite of the preparation of the coatings at a bed temperature about 20 degrees C above MFT, the release from the diffusion pellets is not stable during storage. Only curing in an oven or in the fluidized bed up to a certain limiting release rate at 80 degrees C for 1 h results in stable products. Increased relative humidity allows reduction of the curing temperature. The water soluble additives polyoxy ethylene (PEG) and polyvinyl pyrrolidone (PVP) and insoluble additives are ineffective as pore formers.

Acrylic Resins↗
PubMed2001

Post-stroke dementia. Nootropic drug modulation of neuronal nicotinic acetylcholine receptors.

Nefiracetam is a new pyrrolidone nootropic drug that is being developed for clinical use in the treatment of post-stroke vascular-type and Alzheimer's-type dementia. Among a few neuroreceptors that have been identified as potential targets of nootropics, neuronal nicotinic acetylcholine receptors (nnAChRs) are deemed the most important since they are related to learning, memory, and Alzheimer's disease dementia. We have recently found potent stimulating action of nefiracetam on nnAChRs. Rat cortical neurons in long-term primary culture expressed nnAChRs. Whole-cell patch clamp experiments revealed two types of currents induced by ACh, alpha-bungarotoxin (alpha-BuTX)-sensitive, rapidly desensitizing, alpha 7-type currents and alpha-BuTX-insensitive, slowly desensitizing, alpha 4 beta 2-type currents. Although alpha 7-type currents were only weakly inhibited by nefiracetam, alpha 4 beta 2-type currents were potently and efficaciously potentiated by nefiracetam. Nefiracetam at 0.1 nM reversibly potentiated ACh-induced currents to 200-300% of control. Very high concentrations (about 10 microM) also potentiated these currents, but to a lesser extent, indicative of the bell-shaped dose-response relationship known to occur for nefiracetam, even in animal behavior experiments. Three specific inhibitors of each of PKA and PKC did not prevent nefiracetam from potentiating ACh-induced currents, indicating that these protein kinases are not involved in nefiracetam action. Pretreatment with pertussis toxin did not alter nefiracetam potentiation, indicating Gi/Go proteins are not involved. Pretreatment with cholera toxin did abolish nefiracetam potentiation. Thus, nefiracetam potentiation is mediated via Gs proteins. In conclusion, nefiracetam stimulates alpha 4 beta 2-type nnAChRs via Gs proteins at nanomolar concentrations. The potentiation of alpha 4 beta 2-type nnAChRs is thought to be at least partially responsible for cognitive enhancing action.

Acetylcholine↗
PubMed2001

Extraction of human DNA for PCR from chewed residues of betel quid using a novel "PVP/CTAB" method.

Residues of chewed betel quid (BQ) are often found on crime scenes in Taiwan and possibly some of the Southeast Asian countries. Although these residues are important biological evidences relating to the suspects, the forensic analysis of BQ evidence has been hindered by failures in extraction of human DNA for PCR analysis. Therefore, it is a prerequisite for relevant forensic casework to establish a reliable method for extracting DNA from chewed BQ residues. Three conventional methods (salt/chloroform, 5% Chelex-100 resin, and QIAamp) were first tested for extraction of human DNA from 33 mock BQ samples, which had been stored for less than two months, and 50 four-year-old forensic BQ samples. PCR amplifications from the HLA-DQA1&PM and the STR loci were then used to test the quality of the extracted DNA. For the mock samples, three observations were made. First, PCR amplification of DNA extracted by using these conventional methods had low success rate. Second, the addition of extra Taq DNA polymerase could compensate the lost enzyme activities due to putative inhibitors and, thus, increase the yield. Third, using the Centricon-100 column to remove putative inhibitors substantially improved the efficiency of PCR. However, for the four-year-old forensic BQ samples, none of the attempts for PCR were successful. In order to solve the problem in PCR analysis of DNA from old BQ samples, we developed a DNA extraction method based on the use of polyvinyl pyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB), which bind to two common classes of PCR inhibitors in plants, polyphenols, and polysaccharides, respectively. The result showed that this "PVP/CTAB" method is completely successful for the mock BQ samples, and 92% (46 out of 50) successful for the four-year-old forensic BQ samples. To our best knowledge, this is the first report of a reliable method for the extraction of human DNA for PCR from chewed BQ residues. This method should provide a useful means for forensic identification in countries where betel chewing is common.

Areca↗
PubMedDate not supplied

Qualitative and quantitative analysis of new amino acid derivatives of anticonvulsant activity.

Qualitative and quantitative methods for analysis of three new amino-acidic anticonvulsants of low neurotoxicity: pyrazole-3,5-dicarboxylic acid benzylamine (1), pyrazine-2-carboxylic acid benzylamine (2) and (R, S) N-acetyl-2-pyrrolidone-5-carboxylic acid benzylamide (3) have been developed. Qualitative analysis included characteristic reactions, chromatographic (TLC) investigations, IR and UV spectra interpretation and quantitative analysis involved spectrophotometric, chromatographic (HPLC) and acidimetric methods.

Amino Acids↗
PubMed2002

Metadoxine in acute alcohol intoxication: a double-blind, randomized, placebo-controlled study.

BACKGROUND: At present there are only intriguing and preliminary clinical results regarding the efficacy of metadoxine (pyridoxol L-2-pyrrolidone-5-carboxylate) in acute alcohol intoxication. The present study was planned with the aim of investigating the effectiveness of metadoxine in the management of patients affected by acute ethanol intoxication. METHODS: A double-blind, randomized, multicenter, placebo-controlled trial was carried out on 58 patients of both sexes with acute ethanol intoxication. Patients were treated with a single dose of 900-mg intravenous metadoxine (n = 29) or with placebo (n = 29). Patients were clinically and biochemically evaluated at 0.5, 1, 2, 3, 6, 9, and 12 hr after treatment. RESULTS: Treatment with metadoxine significantly decreased the half-life of ethanol in blood (from 6.70 +/- 1.84 to 5.41 +/- 1.99 hr; p < 0.013) and showed a faster rate of ethanol elimination. The effects on ethanol half-life in blood were accompanied by a faster onset of recovery from intoxication, defined as the time of the transition of blood ethanol levels to the immediately lower range defined by intoxication categories (in g/liter: 0 to 0.5, absent; 0.51 to 1.0, mild; 1.1 to 2.5, moderate; >2.5, severe). Thus the median time to onset of recovery was 0.95 hr with metadoxine and 2.34 hr with placebo (p = 0.013). The effects of treatment on blood alcohol levels were paralleled by a significant decrease in the rating of the toxic clinical symptomatology. At 2 hr the improvement of toxic symptoms (in percent of maximum possible) was 68 +/- 28 vs. 44 +/- 27% in controls (p < 0.002). CONCLUSIONS: In patients with acute ethanol intoxication metadoxine accelerated the elimination of ethanol from blood, which led to faster recovery from intoxication, and improved the behavioral toxic symptomatology. Metadoxine could be helpful in the management of acute ethanol intoxication.

Adult↗
PubMed2002

[NMF and cosmetology of cutaneous hydration].

In the stratum corneum, the water binds to the intracellular hygroscopic and hydrosoluble substances called "natural moisturizing factors" or NMF. These "natural moisturizing factors" contained in the corneocytes are formed during epidermal differentiation and may represent up to 10 p. cent of the corneocyte mass. They are principally amino acids, carboxylic pyrrolidone acid, lactic acid, urea, glucose and mineral ions. Keratinization plays an important part in the formation of NMF that exhibit strong osmotic potential attracting the water molecules. The binding of water to NMF is the static aspect of cutaneous hydration. The second, dynamic, aspect is related to the selective permeability of the stratum corneum and to its lipid barrier properties, the permeability of which depends on the integrity and nature of the inter-corneocyte lipids and their lamellar organization between the cells. In these conditions, hydration cosmetics rely on two concepts that can be isolated or associated: the supply of hydrophilic substances to the stratum corneum, capable of attracting and retaining water (moisturizer) or capable of restoring the barrier in order to restore normal water loss or of protecting it against aggression (occlusive).

Body Water↗
PubMedDate not supplied

[Immobilization of commercial glucoamylase on the polymer carrier].

Commercial glucoamylase was immobilized on the polymer carrier produced by the binding of 4--8 mol.% 4,4'-diamine diphenyl oxide of the maleic anhydride copolymer with N-vinyl pyrrolidone. Two types of immobilized preparations were obtained: with covalent absorption and covalent attachment of the enzyme to the polymer. Glucoamylase activity of the first preparation was 20,000--60,000 and that of the second was 40--120 units/g polymer. Covalent-attached preparations showed a more prolonged action than covalent-absorbed ones.

Enzymes, Immobilized↗
PubMed2002

Evaluation of CC2 as a decontaminant in various hydrophilic and lipophilic formulations against sulphur mustard.

OBJECTIVE: To evaluate CC2 (N, N'-dichloro-bis [2, 4, 6-trichlorophenyl] urea) in various hydrophilic and lipophilic formulations as a personnel decontaminant for sulphur mustard (SM). METHODS: Twenty percent of CC2 was prepared as a suspension or ointment with various chemical agents and its stability was evaluated by active chlorine assay. The efficacy was evaluated in mice by recording the mortality after applying 29 LD50 of SM (LD50 = 8.1 mg/kg dermally) and decontaminating it after 2 min with 200 mg of the formulation. Studies were also carried out with 10% and 20% CC2 in acacia and hydroxypropyl cellulose, and the suspensions were stored in polyethylene containers. The stability of the suspensions was evaluated by active chlorine assay. The efficacy was evaluated by recording the mortality after applying 29 LD50 of SM in mice and 12 LD50 of SM in rats (LD50 = 2.4 mg/kg dermally), and decontaminating it with the formulations. LD50 by different routes and primary skin irritation test of CC2 were also carried out. RESULTS: CC2 reacted with peanut oil and neem oil, and was unstable in povidone iodine and Fuller's earth. Good stability was achieved with petroleum jelly, honey, polyvinyl pyrrolidone, calamine lotion, acacia and hydroxypropyl cellulose. Though CC2 was stable in lipophilic formulations, it did not protect the animals. The hydrophilic formulations particularly acacia and hydroxypropyl cellulose gave very good protection and was stable in the polyethylene containers for a period of 1 year. The efficacy of 20% CC2 was better than 10% CC2. The oral and dermal LD50 of CC2 was found to be above 5.0 g/kg. CC2 was also found to be nonirritant. CONCLUSION: Twenty percent of CC2 in hydroxypropyl cellulose is better with respect to stability, efficacy and ease of decontamination. CC2 is also a safe chemical.

Administration, Cutaneous↗
PubMedDate not supplied

[Effect of prolonged administration of thyrocalcitonine on mineralization of regenerating bone after fracture].

A distinct effect on all the stages of regenerating bone mineralisation was observed after daily (within the experimental period) intramuscular administration of thyrocalcitonine with prolonged action (a complex with polyvinyl pyrrolidone) into male rat at a dose 2.5 un/kg of body weight. The drug caused an inhibitory effect on metabolism within the first 10 days of the experiment. Within 2-3 weeks after the fracture the intensity of metabolic processes was increased. Contents of calcium, phosphorus, sodium and potassium were markedly increased in liquid phase of the bone rissue. The synthesis of phosphoproteins, organic non-protein phosphates and the inorganic phosphate was also increased. The data obtained suggest that thyrocalcitonine caused a stimulating effect on aerobic resynthesis of macroergic phosphate containing substances and the increase in the functional activity of osteogenic cells.

Animals↗
PubMed2002

Influence of storage time and temperature on the stability of indomethacin Pluronic F-127 gels.

The stability of 20 topical gel formulations containing drug, 1% w/w indomethacin (IND), and 20% w/w Pluronic (PF-127) as a gel-forming agent, hexylene glycol (HG) and polyethylene glycol 300 (PEG) in different amounts (16, 20 and 24% w/w) as solvents and 1% w/w polyvinyl pyrrolidone (PVP, K-25) and Tween as excipients was determined by appearance and consistency of the gels, microscopy, pH and rheological measurements after 1 and 4 weeks storage, at 6 degrees C, 20 +/- 2 degrees C and 45 degrees C. Viscosity values were determined from rheograms by a Haake Rotovisco sensor at shear rates of 1000 to 10,000 l/s. The relationship between effectors (temperature and storage time) and response (viscosity) was determined using multiple regression analysis. All formulations were stable at room temperature (20 +/- 2 degrees C). The consistency of the gels containing HG and PEG decreased during storage at 6 degrees C. Storing the gels at 6 degrees C resulted in the precipitation of IND, but when PVP was incorporated into the IND-PF-127 gels, the stability of the gels was improved. All IND gels sustained their pseudoplastic flow behaviour. The viscosity decreased as storage time increased. A statistically significant model was obtained, showing that the effect of storage temperatures on the viscosity was much less than the effect of storage time.

Chemical Phenomena↗
PubMed2002

[Adsorption of neutral polymers on liposomes: investigation of the correlation between liposomes and polymers].

The characteristics of the adsorption process of neutral polymers: poly(vinyl alcohol), poly(vinyl pyrrolidone), and dextrane onto liposomes with three different lipid compositions were investigated as follows. 1 determination of the amount of polymers adsorbed on the surface of liposomes, 2 detection of the changes in the membrane structure brought by the adsorption of polymers with a high precision densimeter, 3 test dye release experiments with membrane diffusion cells after remote loading of liposomes with acridine orange (AO). The amount of polymers adsorbed on the surface of liposomes was expressed with adsorption isotherms at 25 +/- 1 degrees C. Connections were found between the lipid composition influencing the fluidity of liposome membrane, the surface charge density of liposomes, the physical-chemical properties of the polymers and the quantitative adsorption properties of the polymers. Decreasing of the molar excess volume values counted from the results of the high precision densimetric measurements revealed the compression of the membrane structure caused by polymer adsorption. We were able to influence the test dye (AO) release properties of the soy lecithin phospholipid (SLPL)/cholesterol (Chol)/dicethyl phosphate (DCP) = 25:3:2 (mol/mol) liposomes by the changing of the amount of PVA or DEX added to their dispersions.

Adsorption↗