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Biomedical subjects

V Dorneanu

Publications and source records attributed to V Dorneanu.

At least 19 recordsLinked to original sources
PubMed2002

Schiff bis bases: analytical reagents. II. Spectrophotometric determination of manganese from pharmaceutical forms.

By condensing ethyl-o-hydroxybenzene with ethylene diamine, and 1-ethyl-salicylidene bis ethylene diamine, a Salen-type Schiff bis base is obtained. These Schiff bis bases present a good capacity of complexing the Mn(II) ions, resulting brown complexes. In this paper, the results of a study concerning the use of the Schiff bis base as reagent in spectrophotometric determination of the Mn(II) is presented. The above mentioned Schiff bis base forms a brown complex with Mn(II) cation, with maximum absorbance at 460 nm, and molar absorbtivity (epsilon)=9.8 x 10(4). The complex with Mn(II) presents a maximum stability at pH 6.0. The combination ratio was established by isomolar series method, and it is 1:2 (metal:ligand). The calculated apparent stability constant is beta(n)=2.943 x 10(-5). The absorbance is proportional to Mn(II) concentration in the range of 10-70 microg ml(-1). In this range, the Lambert-Beer law is respected, the linearity coefficient being 0.9989, S.D.=0.83, R.S.D.=0.88 (n=7). In these conditions, the complexation reaction of Mn(II) is interfered by other cations, Fe(II); Fe(III); Ni(II). The results obtained for spectrophotometric determination of Mn(II) using this Schiff base as reagent were successfully applied to pharmaceutical products containing Mn(II) cation.

Indicators and Reagents↗
PubMedDate not supplied

Prolonged gastroprotective activity of a ranitidine-dextran conjugate.

The paper presents the influence of the ranitidine-dextran conjugate on the gastric secretion stimulated with carbachol on rats with a ligated pylorus [correction of ligaturated pilor]. The gastric lesions, the gastric juice volume and the total acidity at 6, 24 and 48 hours after the treatment were examined. Ranitidine serum content was determined by HPLC. Administration of the ranitidine-dextran conjugate produces a higher inhibition of gastric lesions at 48 hours than the administration of the free drug (61.4% versus 33.9%) and a prolonged action for more 48 hours. Synthesis of a macromolecular prodrug of ranitidine and its in vitro behavior was reported in a previous paper (11). The present paper studies the performances obtained in gastro-protective action by using the new ranitidine-dextran conjugate reported (11).

Animals↗
PubMedDate not supplied

[Ion-selective electrodes with a liquid membrane for determining N-butylscopolammonium bromide].

Two ion-selective electrodes with liquid membrane for N-butylscopolamonium bromide are described, with N-butylscopolamonium tetraphenylborate (I) and N-butylscopolamonium reineckate (II), respectively, solved in benzylic alcohol as electroactive material. These electrodes have a linear response in the concentration range of 10(-2)-10(-6) M N-butylscopolamonium bromide, with the detection limit of 10(-7) M for both electrodes. These electrodes were used with good results for quantitative assay by direct potentiometry of injectable solutions of N-butylscopolamonium bromide.

Butylscopolammonium Bromide↗
PubMedDate not supplied

Cyclosporine bioavailability of two physically different oral formulations.

To assess the comparative bioavailability of two cyclosporine capsule products with different pharmaceutical formulation an open randomized two-period cross over study was conducted in 24 healthy volunteers. Our results, obtained from cyclosporine HPLC determination onto the whole blood samples collected, show that the test cyclosporine non-SMEDDS formulation was not bioequivalent cyclosporine SMEDDS formulation due to a statistically significantly lower absorption rate. The outcome does not support free and full interchangeability in chronic stable graft recipients of the two products studied, unless validated clinical and laboratory conversion protocols for each kind of organ transplantation are enforce.

Area Under Curve↗
PubMedDate not supplied

[The physicochemical characterization and therapeutic evaluation of Cicatrol].

Cicatrol ointment with the formula: argentic sulphamethoxydiasine 1 g, bentonite hydrogel 12.5% for 100 g is manufactured at the Microproduction Laboratory of the Faculty of Pharmacy of Iaşi. The one-year physicochemical determinations of the aspect, colour, homogeneity, pH, rheological behaviour and relative viscosity, content in argentic sulphamethoxydiasine as well as "in vitro" antimicrobial activity of Cicatrol showed a good stability and gel properties enabling an uniform and long-term contact with the wound. The clinical investigations carried out until now in patients with burns, varicose ulcers, trophic shank ulcers, superficial phlebitis with atonic ulcerations or wounds with multiple sites revealed its remarkable therapeutic value. As compared to other similar products, Cicatrol by its aseptic properties favours the scarring of any type of wound, a normal skin, without keloid scars being obtained, it also being well tolerated.

Burns↗
PubMedDate not supplied

[VIS spectrophotometry used for quantitative determination of iodide in food products of animal origin].

The spectrophotometric method used in dozing the iodides in the water, has been studied in order to use it in determining the iodides in a series of food products. This method is based on the catalyzed reduction of the iodide of Ce4+ by the arsenious acid. In order to determine the iodide in several food products of animal origin (eggs, milk and meat), the sample is first treated with a concentrated KOH solution and is maintained on a water bath until is obtained a residue; this is then subjected to calcination at temperatures of 500-600 degrees C until a perfectly white ash is obtained. After cooling, the ash is dissolved in water, concentrated H2SO4 is added and is completed with water up to a certain volume. The thus obtained solution is used for determination of the iodide in food, according to the method described above. The content of iodide (microgram%) have been calculated with the relation deduced from the equation of the regression line delineated in VIS at 459 nm. The method is selective and the procedure is widely applicable to the determination of iodide in different food products of animal origin.

Algorithms↗
PubMedDate not supplied

[Pharmacognostic research of some species of Achillea. Note 1. Volatile oils analysis].

We established the hydrodistilled essential oil yields from the dried flower heads of A. collina J. Becker ex Reichenb. (collected in Austria and Romanina), A. millefolium L. (s.l.) (Romania) and of three mixtures of some species belonging to the Achillea millefolium L. group. Constitutents of the essential oils were studied by GC method. The main components of the monoterpene fraction of the oils were 1.8 cineol, camphor, and borneol. The main active principle of the volatile oil, chamazulene, was in highest concentration (53%) in the essential oil hydrodistilled from A. collina collected in Austria. The results obtained for a mixture of some species (Plafar Botoşani) differ from literature data in the presence of bisabolol, which have not been found so far in Achillea species.

Achillea↗
PubMedDate not supplied

[Visible spectrophotometric assay of ranitidine].

Ranitidine, belonging to H2-antagonist group, is a compound containing a furanic moiety and is used in peptic ulcer therapy. This paper debates the possibility of developing a new visible spectrophotometric assessment by using the reaction between ranitidine and eosine. We carried out our determinations at 505 nm, where the absorbency of ranitidine-eosine complex is maximal, and we have established the optimal reaction conditions. This method was successfully applied for ranitidine assay from pharmaceutical dosage forms.

Algorithms↗
PubMedDate not supplied

[Membrane-selective electrode for atropine assay].

One membrane-selective electrode with PVC matrix for atropine is described, with atropine tetraphenylborate as electroactive material. This electrode has a linear response in the concentration range of 10(-2)-10(-5) M atropine sulphate, with a detection limit of 3.29 x 10(-6) M. This electrode was used with good results for quantitative assay by direct potentiometry and potentiometric titration of atropine sulphate from pharmaceutical formulations.

Algorithms↗
PubMedDate not supplied

[Schiff base type onno spectrophotometric determination of magnesium].

By condensing hydrazide salicylic acid with o-hydroxy carbonilic compounds it was obtained 2--hydroxy acetophenon--salicyl hidrazina, Schiff base--type ONNO. These Schiff bis bases present a good capacity of complexing the Mg (II) ions. The above mentioned Schiff base forms complex with Mg (II) cation, with maximum absorbance at 386 nm, and molar absorbtivity (epsilon) = 6.27 x 10(4) mol-1.L.cm-1. The complex with Mg (II) presents a maximum stability at pH = 9.6 - 10.0. The calculated apparent stability constant is K = 3.18 x 10(3). The absorbance is proportional to Mg (II) concentration in the range of 10-60 mg/mL. In this range, the Lambert--Beer law is respected, the linearity coefficient being 0.9818, SD = 0.83, RSD = 0.84 (n = 6). The results obtained for spectrophotometric determination of Mg (II) using this Schiff base as reagent were successfully applied to pharmaceutical products containing Mg (II) cation.

Algorithms↗
PubMedDate not supplied

[UV spectrophotometry used for quantitative determination of oleanolic acid].

In order to adapt the UV spectrophotometry method to oleanolic acid dosing, absorption spectra within the range from 230 to 350 nm have been determined for both OA systems in glacial acetic acid (lambda max = 256 nm) and OA systems in ethyl alcohol (lambda max = 277 nm). The time stability of oleanolic acid in the presence of the two solvents has also been investigated in this study. Besides, the composition of etalon series and graphical representation of experimental results (n = 6) have been performed. Also, the calculation algorithm was given, the regression lines have been drawn and statistical parameters were calculated to establish the mathematical expression of OA concentration (mg%).

Algorithms↗
PubMedDate not supplied

[UV spectrophotometric assay of famotidine in combination with picrolonic acid, picrolinate].

Famotidine, belonging to H2-antagonist group, is a compound containing a thiazolic moiety and it is used in peptic ulcer therapy. This paper debates the possibility of developing a new ultraviolet spectrophotometric assessment by using the reaction between famotidine and picrolonic acid. We carried out our determinations at 362 nm, where the absorbency of famotidine - picrolonic acid complex is maximal, and we have established the optimal reaction conditions. This method was successfully applied for famotidine assay from pharmaceutical dosage forms.

Anti-Ulcer Agents↗
PubMedDate not supplied

[Membrane-selective electrodes for drug analysis. Note II].

Seven membrane-selective electrodes with PVC matrix and liquid-membrane for N-butylscopolamine with different electroactive materials are presented. These electrodes have a linear response in the concentration range of 10(-6) - 10(-2) M N-butylscopolamine bromide, with a detection limit between 4.58 x 10(-7)M and 1.09 x 10(-6)M. These electrodes were used with good results for quantitative assay by direct potentiometry and potentiometric titration of N-butylscopolamine bromide from pharmaceutical formulations. Recovery was between 95.50% and 99.20% for N-butylscopolamine bromide of injectable solutions.

Algorithms↗