Ni ions doped oxyflourophosphate glass as a triple ultraviolet-visible-near infrared broad bandpass optical filter.

Research and development R&D about new materials that can be used as an optical filter, shortpass, bandpass, and longpass is still ongoing. So, in this context, the 50P2O5-20ZnF2-15MgF2-15PbF2 doped different concentrations of NiO ranging from 0 up to 4 mol% as a bandpass filter was prepared using the conventional melt annealing method. The formation of the amorphous essence was observed in the X-ray diffraction patterns. The role of Ni ions in the produced glass network was studied by density and Fourier Transform Infrared FTIR spectroscopy results, which showed that the Ni ions play a network modifier role. Thermal analysis results showed high thermal stability for the produced glasses. Electron paramagnetic resonance EPR spectra results clarified that the Ni3+ ions occupy an elongated octahedral [Formula: see text]. The measurements of AC conductivity, dielectric constant, and electric modulus were studied at different temperatures and frequencies. The ionic conduction dominates the conductivity at high temperatures, while the electronic dominates at low temperatures. The appearance of Ni3+ (confirmed by ESR) and Ni2+ were observed in the optical absorption spectra, also it was found that both of them occupy both tetrahedral and octahedral sites. Three distinguished bands in the UV (centered at 354 nm), visible (centered at 620 nm), and NIR (centered at 1074 nm) regions appeared in the optical transmittance spectra, indicating the defining characteristic of the bandpass filter.

A prospective study of three diagnostic sonographic methods in differentiation between benign and malignant salivary gland tumours.

OBJECTIVE: The aim of this study was to evaluate the role of three diagnostic sonographic methods, greyscale sonography (GSS), colour Doppler sonography (CDS) and spectral Doppler (SPD), in differentiating between benign and malignant salivary gland (SG) tumours. METHODS: 44 patients with SG masses were examined using GSS, CDS and SPD. The morphological features of each tumour were evaluated using GSS, the distribution and number of detected blood vessels were assessed using CDS, and peak systolic velocity (PSV), resistive index (RI) and pulsatility index (PI) were measured on SPD. All cases underwent excisional biopsy and a definite tissue diagnosis was obtained. RESULTS: Histopathological examination revealed that 28 of the 44 tumours were benign and 16 were malignant. GSS showed that malignant SG tumours had a significantly higher incidence of ill-defined borders and lymph node involvement than benign tumours, but there was no significant difference between benign and malignant SG tumours regarding echogenicity, homogeneity or sonographic shape. CDS demonstrated malignant tumours with significantly higher vascularity and a scattered distribution. Using SPD, malignant tumours had significantly higher PSV, RI and PI compared with benign tumours. CONCLUSION: RI values above 0.7, PI values above 1.2, PSV values above 44.3 cm s(-1), ill-defined borders, lymph node involvement, Grade 2 or 3 vascularity and hilar distribution of blood vessels should alert the clinician to suspect a malignant SG tumour. After consensus on the threshold values of PSV, RI and PI in differentiating benign from malignant SG tumours, these numbers should be incorporated into the software of ultrasound machines to guide the sonographer in his or her analysis.

Development of membrane electrodes for the selective determination of hyoscine butylbromide.

Four polyvinyl chloride (PVC) membrane sensors for the determination of hyoscine butylbromide are described and characterized. The sensors are based on the use of the ion association complexes of hyoscine cation with ammonium reineckate counter anions as ion exchange sites in the PVC matrix. The membranes incorporate ion association complexes of hyoscine with dibutylsebathete (sensor 1), dioctylphthalate (sensor 2), nitrophenyl octyl ether (sensor 3) and beta-cyclodextrin (sensor 4). The performance characteristics of these sensors were evaluated according to IUPAC recommendations, which reveal a fast, stable and linear response for hyoscine over the concentration range of 10(-5)-10(-2)M for sensors 1 and 2 and 10(-6)-10(-2) for sensors 3 and 4 with cationic slopes of -53.19, -55.17, -51.44 and -51.51mV per concentration decade for the four sensors, respectively. The direct potentiometric determination of hyoscine butylbromide using the proposed sensors gave average recoveries % of 99.92+/-1.11, 99.93+/-1.00, 99.94+/-1.18 and 99.87+/-1.39 for the four sensors, respectively. The sensors are used for determination of hyoscine butylbromide in laboratory prepared mixtures, pharmaceutical formulations in combination with ketoprofen and in plasma. Validation of the method shows suitability of the proposed sensors for use in the quality control assessment of hyoscine butylbromide. The developed method was found to be simple, accurate and precise when compared with a reported HPLC method.

Application of new membrane selective electrodes for the determination of drotaverine hydrochloride in tablets and plasma.

The construction and electrochemical response characteristics of poly vinyl chloride (PVC) membrane sensors for the determination of drotaverine hydrochloride were described. The sensors are based on the use of the ion association complexes of drotaverine cation with sodium phosphotungestate (Dro-PTA) or ammonium reineckate (Dro-R) counter anions as ion exchange sites in the PVC matrix. The performance characteristics of these sensors, which were evaluated according to IUPAC recommendations, reveal a fast, stable and linear response for drotaverine over the concentration range 10(-5) to 10(-2) M with cationic slopes of 49.55 and 51.36 mV per concentration decade. The direct potentiometric determination of drotaverine hydrochloride using the proposed sensors gave average recoveries of 99.95+/-0.71 and 100.04+/-0.60 for Dro-PTA and Dro-R, respectively. The sensors are used for determination of drotaverine hydrochloride in tablets, in its mixture with caffeine and paracetamol and in plasma. Validation of the method shows suitability of the proposed sensors for use in the quality control assessment of drotaverine hydrochloride. The developed method was found to be simple, accurate and precise when compared with a reported HPLC method.

Stability-indicating spectrophotometric and densitometric methods for determination of aceclofenac.

Three methods were developed for the determination of aceclofenac in the presence of its degradation product, diclofenac. In the first method, third-derivative spectrophotometry (D3) is used. The D3 absorbance is measured at 283 nm where its hydrolytic degradation product diclofenac does not interfere. The suggested method shows a linear relationship in the range of 4-24 micrograms mL-1 with mean percentage accuracy of 100.05 +/- 0.88. This method determines the intact drug in the presence of up to 70% degradation product with mean percentage recovery of 100.42 +/- 0.94. The second method depends on ratio-spectra first-derivative (RSD1) spectrophotometry at 252 nm for aceclofenac and at 248 nm for determination of degradation product over concentration ranges of 4-32 micrograms mL-1 for both aceclofenac and diclofenac with mean percentage accuracy of 99.81 +/- 0.84 and 100.19 +/- 0.72 for pure drugs and 100.17 +/- 0.94 and 99.73 +/- 0.74 for laboratory-prepared mixtures, respectively. The third method depends on the quantitative evaluation of thin-layer chromatography of aceclofenac using chloroform:methanol: ammonia (48:11.5:0.5 v/v/v) as a mobile phase. Chromatograms were scanned at 274 and 283 nm for aceclofenac and diclofenac, respectively. The method determined aceclofenac and diclofenac in concentration ranges of 2-10 and 1-9 micrograms spot-1 with mean percentage accuracy of 100.20 +/- 1.03 and 100.14 +/- 0.98 for pure drugs and 99.77 +/- 0.74 and 100.07 +/- 0.78 for laboratory-prepared mixtures, respectively. This method retains its accuracy in the presence of up to 80% degradation product for the studied drug. The suggested procedures were checked using laboratory-prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparation. The validity of the proposed methods was further assessed by applying a standard addition technique. The obtained results agreed statistically with those obtained by the reported method.

Stability indicating methods for assay of mequitazine in presence of its degradate.

Six procedures have been suggested for the determination of the antihistaminic agent, mequitazine, in the presence of its degradate. Mequitazine, having a phenothiazine group, undergoes peroxide oxidation and the corresponding sulphone is produced. Its identity was confirmed by IR and MS. The first procedure is based on determination of mequitazine by HPLC with UV detection at 256 nm. The mobile phase used is acetonitrile, ortho phosphoric acid (50:50) using caffeine as an internal standard. Linearity range is 1.00-9.00 microg/ml. The second determination is a densitometric procedure based on the determination of mequitazine in the presence of its degradate at 256 nm using the mobile phase, chloroform:methanol:ammonia (50:18:3). Linearity range is 1.25-7.50 microg per spot. The third procedure is spectrophotometric, where a mixture of mequitazine and its degradate are resolved by first derivative ratio spectra. Linear calibration graphs of first derivative values at wavelengths 210.2, 247 and 259.8 nm are obtained. On carrying out measurements at the three mentioned wavelengths, the linearity range is found to be 1.00-10.00 microg/ml. The fourth procedure is based on first derivative spectrophotometry, where D(1) measurements are carried out at 290 nm. Linearity range is 1.00-10.00 microg/ml. The fifth procedure is based on the reaction of mequitazine with 3-methyl-2-benzothiazolinone hydrazone (MBTH) in the presence of ferric chloride. A stable violet colored oxidative coupling product is formed, which is measured spectrophotometrically at 685 nm. The optimum experimental parameters for the reaction have been studied and assigned. Linearity range is 1.00-16.00 microg/ml. The sixth procedure is based on the reaction of mequitazine in the presence of its degradate with 2,6-dichloroquinone-4-chloroimide (Gibbs reagent) in aqueous methanolic medium. The reddish-brown colored condensation product is measured at 405 nm. The optimum experimental conditions for the reaction have been studied. Linearity range is 50.00-600.00 microg/ml. The validity of the described procedures was assessed by applying the standard addition technique. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The suggested procedures could be used for the determination of mequitazine, both in pure and dosage forms, as well as in the presence of its degradate.

Stability indicating method for determination of nortriptyline hydrochloride using 3-methyl-2-benzothiazolinone hydrazone (MBTH).

A spectrophotometric procedure is described for determination of nortriptyline hydrochloride in pure and dosage form as well as in the presence of its degradate. 3-Methyl-2-benzothiazolinone hydrazone (MBTH) has been used as the chromogenic reagent, where aqueous solutions of the drug and reagent are treated with cerium(IV) ammonium sulphate in an acidic medium. Nortriptyline hydrochloride reacts to give a blue coloured product having two absorption maxima at 619 and 655 nm. Various parameters affecting the reaction have been studied. Beer's law is obeyed in the concentration range of 24-216 microg ml(-1) of nortriptyline hydrochloride, with mean percentage recoveries of 100.22+/-0.870 and 100.66+/-0.642% for both maxima, 619 and 655 nm, respectively. Results were statistically analyzed and compared with those obtained by applying the British Pharmacopoeia (1993) method.

Stability-indicating methods for the spectrophotometric determination of norfloxacin.

Two spectrophotometric procedures for the selective determination of norfloxacin (NF) in the presence of its decarboxylated degradant are described. The first depends upon measurement of the pH-induced absorbance difference (delta A) of the drug solution between 0.1 N HCl and 0.1 N NaOH at 280 nm. The second involves chelation of the intact drug with iron (II) in acetate buffer solution (pH 5.7 +/- 0.1) to form a yellow-coloured chelate which absorbs at 358 nm. The two procedures are applied successfully for the determination of the intact drug both in pure form and in tablet form. The two methods retain their accuracy in the presence of up to 62% and 76% degradants, respectively.

Hallucinogenic receptor models: interaction of imidazolium chloride with amphetamine analogs.

The interactions of several hallucinogenic phenethylamines with the biologically relevant electron acceptor imidazolium chloride have been investigated by monitoring phenethylamine 1H NMR chemical shift changes upon complex formation. Methoxy- and methylenedioxy-substituted phenethylamines interact with imidazolium chloride to form weak charge-transfer complexes that have a relatively narrow range of association constants. The results indicate the formation of a ternary complex in which a chloride ion is hydrogen bonded to a N+H side chain proton of the drug and a NH imidazolium proton. The imidazolium ring is positioned above a nonsubstituted ortho-position of the aromatic ring. Spectral assignment of the two diastereotopic benzylic protons allowed the geometry of the complex to be defined in more detail. Complexation occurs preferentially on that side of the phenethylamine molecule that allows the side chain alpha-methyl group to face away from the chloride ion and the imidazolium ring. The drug molecule exists in the complex in the preferred trans conformation. The biological relevance of this model is discussed.

Determination of quaternary ammonium surfactants in pharmaceutical formulations by the hypochromic effect.

A spectrophotometric procedure for determination of the quaternary ammonium salts cetrimide (N,N,N-trimethyl-l-hexadecylammonium bromide), cetylpyridinium chloride (l-hexadecyl-pyridinium chloride) and sapamine [N-(2-dimethylaminoethyl)oleamide acetate] in bulk form and some pharmaceutical formulations, such as eye-drops, disinfectant solutions, creams and tablets, is described. Following TLC separation when necessary, addition of an aqueous solution of the active surfactant to a standard amount of Bromothymol Blue, buffered at pH 7.5, leads to an equivalent decrease of the absorbance at 610 nm, which can be taken as an analytical measure of the drug concentration. Good mean recoveries have been obtained for standard additions of these analytes to pharmaceutical formulations containing them.