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Results for “beta-Cyclodextrins”

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PubMed1985

Internalization of cycloheptaamylose-dansyl chloride complex during labelling of surface membrane in living Paramecium aurelia cells.

Internalization of cycloheptaamylose-dansyl chloride complex during surface labelling of living long-term starved Paramecium aurelia cells has been observed. This process may be inhibited by pretreatment of the ciliates with dichloroisoproterenol. Uptake of cycloheptaamylose-dansyl chloride may be visualized only after UV preirradiation: the appearance of orange-fluorescing vacuoles of diameter 2.3-4.5 micron may then be observed. Microspectrographic analysis performed on the cells and dansyl derivatives indicates that this fluorescence is produced by a photochemical reaction of dansyl chloride - released from CDC complex inside the digestive vacuoles-under the influence of UV irradiation.

Animals↗
PubMed1994

Evaluation of piroxicam-beta-cyclodextrin, piroxicam, paracetamol and placebo in post-operative oral surgery pain.

Two hundred ninety-eight patients with post-operative pain after the surgical removal of an impacted third molar were randomly assigned, on a double-blind basis, to receive a single oral dose of piroxicam 20 mg, or piroxicam-beta-cyclodextrin equivalent to 20 mg piroxicam, or paracetamol 500 mg, or placebo. Using a semi-quantitative self-rating scale, patients rated their pain and its relief at 30-min intervals for the first 2 h, and then hourly for 4 h after treatment administration. All active medications were reported to be significantly superior to placebo. The three active drugs were comparable for the degree of analgesia up to the third hour, after which the effect of paracetamol decreased significantly as compared to piroxicam-beta-cyclodextrin and piroxicam. Piroxicam-beta-cyclodextrin and paracetamol were more rapid than piroxicam in inducing analgesia. The tolerability for the active drugs was comparable to that for placebo.

Acetaminophen↗
PubMedDate not supplied

Piroxicam-beta-cyclodextrin in induced migraine attacks: a SPECT study with Tc-99m HM-PAO split-dose method.

To verify the effect of piroxicam-beta-cyclodextrin (P-B-CD), a novel non-steroidal anti-inflammatory compound, on regional cerebral blood flow (rCBF) during migraine attacks, 7 female patients (mean age: 37.4 years), suffering from migraine without aura, were studied. The patients, after induction of a migraine-like attack with sublingual nitroglycerin (NTG), underwent a rCBF evaluation using Single Photon Emission Computerized Tomography (SPECT) and Tc-99m examethyl-propylene-amino-oxyma split-dose method before and after oral administration of P-B-CD (20 mg). In addition, a spontaneous migraine attack and NTG test in 7 control subjects were investigated. All patients observed relief of pain, evaluated by direct and indirect parameters (Pain Intensity; Pain Intensity Difference; Sum of Pain Intensity Difference). SPECT revealed a uniform and symmetrical distribution of the radiocompound in 5 out of 8 patients, while in the remaining 3 symmetrical parietal or parieto-occipital areas of decreased tracer uptake were detected. In these cases, the intake of P-B-CD cancelled out the cerebral perfusion abnormality.

Adolescent↗
PubMed1993

Prizes!

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Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1993

Rheumatic diseases--clinical experience with piroxicam-beta-cyclodextrin.

The clinical relevance of piroxicam-beta-cyclodextrin (PBC) in the long-term treatment of osteoarthritis and rheumatoid arthritis is reviewed. Two hundred and twenty-five patients--one hundred with rheumatoid arthritis and one hundred and twenty five with osteoarthritis--were enrolled in a double-blind, randomised, controlled study versus piroxicam. Drugs were administered once-daily, for twelve weeks. The indices of efficacy (pain intensity, severity of inflammation, functional impairment evaluated at 0,2,4,8 and 12 weeks showed the good analgesic effect of piroxicam without significant differences between its two formulations. Tolerance appeared to be better in the group of patients treated with PBC than in the one treated with piroxicam. Both the incidence and severity of side effects were lower for patients treated with PBC. The majority of side effects were related to the gastrointestinal tract. The study suggests that PBC, used in the long term treatment of rheumatic diseases, improves the safety of piroxicam without affecting its efficacy. In another study, thirty patients with chronic osteoarthritis were randomly assigned to receive PBC or tenoxicam daily for eight weeks. Both drugs effectively reduced pain, inflammation, and functional limitation of the affected joints. Endoscopy revealed minor post-treatment mucosal lesions; these tended to be less severe with PBC than with tenoxicam. The clinical experience in the long-term treatment of rheumatic conditions indicates that the microencapsulation of piroxicam as piroxicam-beta-cyclodextrin has provided a new drug with a superior tolerability compared to the parent compound without affecting its high efficacy on the symptoms of the primary disease.

Adult↗
PubMedDate not supplied

Uptake and metabolism of carcinogenic levels of tobacco-specific nitrosamines by Sudanese snuff dippers.

It was recently reported that toombak, a type of snuff used in the Sudan, contained unusually high levels of tobacco-specific nitrosamines. To estimate the internal dose of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) received by individuals who use this type of tobacco, urine from a group of users was analyzed for 2 metabolites of NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its O-glucuronide, NNAL-Gluc. NNK is a strong lung carcinogen believed to contribute to human lung cancer. NNAL is also a lung carcinogen. NNAL and NNAL-Gluc were analyzed by gas chromatography with a nitrosamine selective detector. The average levels detected were 0.39 +/- 0.14 (SD) nmol/ml urine (n = 7) and 0.88 +/- 0.50 nmol/ml urine (n = 7), respectively. In a 24-h period, these individuals would excrete from 0.12 to 0.44 mg of these two metabolites (expressed per mg NNAL). Therefore, assuming chronic toombak use, the minimum daily dose of NNK to which these users were exposed was 0.12-0.44 mg. This is the highest documented uptake of a nonoccupational carcinogen. Two diastereomers of NNAL-Gluc were present in all urine samples analyzed. Previously, these two diastereomers were identified in the urine of an NNK-treated patas monkey but only one was detected in the urine of NNK-treated rats. The level of the 4-hydroxy-1-(3-pyridyl)-1-butanone releasing hemoglobin adduct was also quantified in these individuals. This adduct is believed to be a measure of NNK activation. The levels ranged from 68 to 323 fmol/g hemoglobin [mean, 148 +/- 104 (SD)]. The wide range of adduct levels which were observed suggests that despite similar levels of NNK exposure, there are significant differences in the ability of individuals in this population to activate NNK, as well as potential differences in their cancer risk.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMedDate not supplied

Effect of dimethyl-beta-cyclodextrin on nitrazepam stability.

Nitrazepam was found to form an inclusion complex with heptakis; 2,6 di-O-methyl-beta-cyclodextrin (DM-beta-CD) in solution. The phase solubility diagram was found to be AL type with no precipitation of the inclusion complex formed. The kinetic studies of nitrazepam hydrolysis in DM-beta-CD solution at 30, 40 and 50 degrees C was followed spectrophotometrically, as the degradation products of the drug did not interfere with such assay. It was found that the degradation of nitrazepam in acidic media followed the first order reaction kinetics at the temperatures studied. Inclusion complexation of nitrazepam in DM-beta-CD resulted in a relatively improved stability of the drug in solution at 30 degrees C. On the other hand, no appreciable stabilization was achieved at higher temperatures (40 and 50 degrees C).

Cyclodextrins↗
PubMed1993

Preparation and central action of propofol/hydroxypropyl-beta-cyclodextrin complexes in rabbits.

Inclusion complexes of propofol (CAS 2078-54-8) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) were examined in aqueous solution and in the solid state by phase solubility technique, IR-spectroscopy and differential scanning calorimetry. Solid complexes obtained by kneading method were dissolved in artificial plasma leading to a colloidal solution which was suitable for intravenous administration. In the in vivo studies propofol (15 mg/kg) was given intravenously to rabbits in equimolar doses as cyclodextrin complexes and as Diprivan. The central action of the drug was verified by recording the bioelectrical activity of the precentral cortex. The statistical evaluation of the results do not indicate differences in onset, duration and maximum of action between the two dosage forms.

Animals↗
PubMed1993

Conditions of cyclodextrin complexation.

In the past 20 years, cyclodextrin (CD) research has achieved considerable results, as indicated by the large number of publications and patents, the six international symposia on CDs, the new dosage forms of medicines prepared with CDs, etc. Sufficient data have accumulated to permit a survey of the most important conditions of CD complexation. Further, an account is presented of the success of precipitation of the complex involving furosemide and beta-CD.

Calorimetry, Differential Scanning↗
PubMed1993

2-Hydroxypropyl-beta-cyclodextrin enhances phorbol ester effects on glucose transport and/or protein kinase C-beta translocation to the plasma membrane in rat adipocytes and soleus muscles.

In rat adipocytes and soleus muscles, 2-hydroxypropyl-beta-cyclodextrin (CD) was found to have a relatively small or no effect on basal or insulin-stimulated hexose uptake, but markedly enhanced hexose uptake effects of phorbol esters and/or diacylglycerol. In rat adipocytes, the CD-induced enhancement of hexose uptake during concurrent phorbol ester treatment was not associated with an increase in GLUT4 glucose transporter translocation to the plasma membrane, which was stimulated comparably by insulin and phorbol esters. Moreover, CD appeared to activate or facilitate the activation of glucose transporters subsequent to their translocation to the plasma membrane during ongoing phorbol ester treatment. In rat adipocytes, CD also enhanced the translocation of protein kinase C (PKC)-beta to the plasma membrane during the action of phorbol esters, which alone had little or no effect on this specific PKC translocation. Although it is uncertain how CD alters the function of plasma membranes to enhance the translocation of PKC-beta to, and the activation of glucose transporters within, this subcellular fraction during phorbol ester treatment, our findings provide direct support for a two-step model in the activation of glucose transport. In addition, it seems clear that, at least in some cell types, simple phorbol ester treatment does not necessarily serve as a ubiquitous activator of all activable PKC pools and all potential PKC-mediated responses.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1993

Cholesterol and 27-hydroxycholesterol 7 alpha-hydroxylation: evidence for two different enzymes.

The use of 2-hydroxypropyl-beta-cyclodextrin as a vehicle for solubilizing cholesterol and 27-hydroxycholesterol has led to a study of their rates of 7 alpha-hydroxylation in microsomal preparations from hamster liver and HepG2 cells. Addition of the vehicle alone to the cholesterol 7 alpha-hydroxylase assay always caused a several-fold increase in activity. Preloading the vehicle with cholesterol further augmented the rate of 7 alpha-hydroxycholesterol formation. Preloading the vehicle with 27-hydroxycholesterol or 27-hydroxycholestanol (molar ratio 1/1.2) minimally decreased cholesterol 7 alpha-hydroxylase activity (-12%), compared with preloading with cholestanol (-50%), a known competitive inhibitor of the enzyme. Microsomes from hamster liver yielded rates of 7 alpha,27-dihydroxcholesterol formation of 1.5 to 3.0 nmol/min per mg protein, compared with 0.3 nmol/min per mg protein for 7 alpha-hydroxycholesterol. Although cholesterol and cholestanol had minimal effects on the rate of 7 alpha-hydroxylation of 27-hydroxycholesterol, addition of an approximately equimolar amount of 27-hydroxycholestanol inhibited the rate of formation by 65%. Attempts to separate and identify the two C-27 sterol 7 alpha-hydroxylases chromatographically led to the finding that Emulgen 913 selectively inactivates 7 alpha-hydroxylation of 27-hydroxycholesterol. These results indicate that the metabolic pathway for bile acid synthesis from 27-hydroxycholesterol is not governed by cholesterol 7 alpha-hydroxylase.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMedDate not supplied

In vitro and in vivo evaluation of o-carboranylalanine as a potential boron delivery agent for neutron capture therapy.

o-Carboranylalanine (B10H10C2CH2CHNH2COOH) is a carborane-containing amino acid, which has been synthesized as a potential capture agent for boron neutron capture therapy (BNCT) of cancer. The purpose of the present study was to develop a rational approach for the in vitro and in vivo evaluation of boron containing compounds that possibly might be used for BNCT. The in vitro uptake of carboranylalanine (CBA) was evaluated using two cell lines, the human melanoma MRA 27, and the murine Harding-Passey melanoma. Uptake of CBA by MRA 27 cells ranged from 135-551 micrograms B/10(9) cells following 3 hrs incubation with medium containing 100-113 micrograms B/ml and was not reduced by exposing the tumor cells to either rotenone, an inhibitor of electron transport, or by culturing them at ambient temperature (approximately 22 degrees C). Cellular uptake and elution of CBA occurred rapidly under in vitro conditions. Uptake of CBA was slightly greater than that of boronophenylalanine (BPA). Following a 3 hr incubation with CBA at a concentration of 106 micrograms B/ml, cell boron content was 255 micrograms B/10(9) MRA 27 cells, compared to 192 micrograms B/10(9) cells when cells were incubated with BPA at a concentration of 95 micrograms B/ml. In vivo studies initially were carried out using the Harding-Passey melanoma, which had been implanted intramuscularly (i.m.) into the right flank of BALB/c mice. Tumors were allowed to grow for 14 days at which time mice were injected intraperitoneally (i.p.) with either CBA or BPA (1.25 mgB/mouse), and were killed 3, 6 and 8 hrs later. CBA attained a low tumor to blood ratio(1.0-1.4), and the tumor boron levels ranged from 15.7-26.2 micrograms B/g at 3 hrs and 3.3-19.9 micrograms B/g at 6 hrs. Higher blood and lower tumor boron levels were observed at all time points with CBA compared to BPA, suggesting that CBA was not taken up selectively by the melanoma. Similar studies, carried out in rats bearing intra-cerebral gliomas, failed to reveal detectable amounts of boron in the tumor. From the present study, it can be concluded that CBA does not appear to possess the requisite properties to be useful as a boron delivery agent for BNCT.

Animals↗