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PubMed1975

Quantitative determination of drugs by means of densitometry of thin-layer chromatograms. Part 5: Determination of the Vitamins B1, B2, B6 and B12 in mixture and in pharmaceutical preparations.

A quantitative t.l.c. densitometric method for the simultaneous determination of the water-soluble vitamins B1, B2, B6, and B12 is proposed. The four vitamins are determined on one and the same plate by direct densitometry of the t.l.c. spots. A preliminary separation of the vitamins one from another, as well as a preliminary separation from other pharmaceuticals is not necessary. The determination is performed quickly and easily. The relative standard deviations of a single determination are the following: for thiamine 6,6%, for riboflavin 5,5%, for pyridoxine 6,4%, and for cyanocobalamin 5,8%. The proposed method is applied to the determination of B-vitamins in three pharmaceutical preparations: ampoules B12 with B1, ampoules B-complex, and antisclerol dragee. The presence of other pharmaceuticals (vitamins C and PP, urethane, aminophenazone, phytin, rutin, theobromine, etc.) does not interfere with the determination.

Chemistry, Pharmaceutical↗
PubMed2001

[A comparison of finger and nose probes in pulse dye-densitometry measurements of cardiac output, blood volume and mean transit time].

We compared finger and nose probes in measurement of cardiac output (CO), blood volume (BV) and mean transit time (MTT) with pulse dye-densitometry. These probes were intraoperatively applied to 6 patients under general and continuous epidural anesthesia. Indocyanine green (ICG) 20 mg, was given via peripheral venous route, and CO, BV and MTT were measured with DDG-2001 (NihonKoden, Japan). Eighteen measurements were done successfully. There was no significant difference between F-CO (CO with a finger probe, 4.48 +/- 1.40 l.min-1, mean +/- SD) and N-CO (CO with a nose probe, 4.14 +/- 1.87 l.min-1). F-MTT (32.9 +/- 11.1 sec) was significantly longer than N-MTT (19.9 +/- 6.4 sec, P < 0.01). The limits of agreement of F-CO and N-CO (mean difference +/- 2 SD) were -3.6 and +4.2 l.min-1, respectively. There was a significant negative correlation between differences in MTT and F-CO/N-CO (R2 = 0.448, P < 0.01). There was no significant difference between F-BV (3.97 +/- 1.23 l) and N-BV (3.97 +/- 0.98 l). The limits of agreement of F-BV and N-BV were -1.3 and +1.3 l, respectively. In conclusion, the measured values in BV showed good agreement and reliability with both finger and nose probes, while CO was less reliable when differences in MTT increased.

Anesthesia, Epidural↗
PubMedDate not supplied

Determination of the active ingredient loperamide hydrochloride in pharmaceutical caplets by high performance thin layer chromatography with ultraviolet absorption densitometry of fluorescence quenched zones.

A quantitative method using silica gel HPTLC plates with fluorescent indicator, automated sample application, and automated UV absorption densitometry of the fluorescence quenching zones was developed and validated for determination of loperamide hydrochloride in anti-diarrheal medications. Samples of three brands of caplets assayed within 96.0-105% of the 2 mg label value. Repeatability was 3.3%, 1.6%, and 2.8% (RSD) for replicate analyses (n=6) of three tablets. The errors of a blank-spike and standard analyses performed to evaluate accuracy were 2.00% and 2.02%, respectively. The method is suitable for application in a drug manufacturing quality control or regulatory analysis laboratory.

Antidiarrheals↗
PubMedDate not supplied

[Development of equipment for bone densitometry].

The paper reviews the development of osteodensitometric equipment. The comparative characteristics of techniques for densitometry are presented. Their advantages and disadvantages are assessed.

Bone Density↗
PubMed2003

[Efficacy of integrated backscatter imaging by acoustic densitometry for identifying ultrasonic tissue characterization of left ventricular thrombus: two case reports].

Echocardiography demonstrated a high echoic lesion(6 x 5 mm) in the apex of the left ventricle of a 72-year-old man(Case 1) and similar lesions(7 x 6 mm and 4 x 3 mm) in the apex of the left ventricle of a 60-year-old man(Case 2). The amplitude of cyclic variation of integrated backscattering of the high echoic lesions was measured by acoustic densitometry to be lower than that of the myocardium in Case 1, but similar to that of the myocardium in Case 2. Contrast echocardiography detected the perfusion defect of the high echoic lesion in Case 1, but not in Case 2 in the apical four-chamber view. These findings showed that the high echoic lesion indicated thrombus in Case 1, and papillary muscle in Case 2. Measurement of the amplitude of the time intensity curve with contrast echocardiography showed that the amplitude of thrombus was different from that of myocardium. This method is useful for ultrasonic tissue characterization.

Aged↗
PubMedDate not supplied

Bone densitometry: an update.

After completing this article on osteoporosis and bone densitometry, readers will be able to: Summarize the economic and psychosocial effects of osteoporosis. Differentiate between primary and secondary causes of osteoporosis. List the risk factors associated with osteoporosis and osteoporotic bone fractures. Describe techniques for preventing osteoporosis. Compare and contrast pharmaceutical agents used to treat osteoporosis. Discuss techniques used to measure bone mineral density, including DXA, pDXA and ultrasound. Know how to prepare and position a patient for a bone density scan and how to minimize radiation exposure to the patient, the technologist and others.

Absorptiometry, Photon↗
PubMedDate not supplied

Mapping size distributions of parenteral fluorocarbon emulsions by a novel method of centrifugal sedimentation followed by densitometry.

A novel method for characterization of size distributions of parenteral fluorocarbon emulsions is described. Prepared emulsions were centrifuged to sediment droplets above predetermined diameters out of a known supernatant sample volume using the Bostok-Stoke's equation. Centrifugation times may be calculated using centrifuge parameters and physical properties of the fluorocarbon oil phase and the dispersion medium. The fluorocarbon content of the supernatant sample volume at successive centrifugation times was determined both by densitometry and by Gas Chromatography. A close correlation was found between the two methods. The density data was processed and converted into a volume distribution histogram by means of a program written in BASIC. The speed, simplicity of use, non reliance on costly equipment and good correlation to absolute particle counting methods makes the density method suitable for submicron size characterization.

Centrifugation↗
PubMed1992

Photographic densitometry for quantitative DNA analysis of cytologic and histologic specimens.

We found that photographic densitometry (PD) is a useful technique for quantitative determinations of nuclear DNA content in clinical tumor material. Optimum conditions for the use of PD in clinical cytology and histopathology were worked out. A quantitative evaluation of the method was performed, particularly with respect to errors that may appear when measuring clinical tumor material. Our study showed that PD offers accurate DNA measurements in cytologic and histologic specimens. Ploidy level determinations in tumor cell populations in clinical material could be as accurately performed with PD as with scanning microspectrophotometry (SMP). Nuclear DNA content of individual cells as determined by PD correlated highly with nuclear DNA content determined by SMP (correlation coefficient, 0.96). Since the PD method is less influenced by background variation than are other image techniques (due to measurement of a photographic image), it is particularly useful in measurement of histopathologic sections, in which the background variation can introduce considerable errors. The method is also valuable with clinical cytologic smears, in which the presence of blood and other material disturbs the background. PD represents a valid complement to scanning microspectrophotometry and TV imaging systems, particularly for DNA analysis of tissue sections. Moreover, it can be applied easily in the clinical routine. Relevant tissue areas are selected and photographed by the pathologist or cytopathologist, and the measurement is performed by a laboratory technician.

Cell Nucleus↗
PubMedDate not supplied

Development and validation of a method for determination of caffeine in diuretic tablets and capsules by high-performance thin-layer chromatography on silica gel plates with a concentration zone using manual spotting and ultraviolet absorption densitometry.

A new quantitative method using silica gel high-performance thin-layer chromatography plates with channels and a concentration zone, manual application of standards and samples, development with methanol-ethyl acetate (15 + 85) mobile phase, and ultraviolet absorption densitometry is reported for the determination of caffeine in diuretic pharmaceutical preparations. Tablet and capsule products containing potassium salicylate, acetaminophen, and salicylamide as active ingredients were analyzed to test the applicability of the new method, and precision, accuracy, linearity, limits of detection and quantitation, and selectivity were validated. The milligrams of caffeine in each tablet ranged from 48.0 to 51.0, and the milligrams in each capsule from 37.9 to 40.3. Within-day precision was 1.48 and 1.78% (n=6), and interday precision 0.723 and 1.26% (n=5) for analysis of 2 tablets and 2 capsules, respectively. Accuracy validation of the tablet and capsule results produced errors of 1.0 and 1.9% for spiked blank analyses and 2.6 and 3.5% for standard addition analyses, respectively. A comparative study using a caffeine standard solution and a multicomponent analgesic tablet solution containing caffeine, acetaminophen, and acetylsalicylic acid showed that manual application on the concentration zone, instrumental application on the concentration zone, and instrumental application on the silica gel gave quite similar results in terms of number of theoretical plates, resolution, limit of detection, and linearity.

Acetaminophen↗
PubMedDate not supplied

Perioperative hemodynamic study of patients undergoing abdominal surgery using pulse dye densitometry.

BACKGROUND/AIMS: Pulse dye densitometry (PDD) using indocyanine-green (ICG) is a newly developed technique for monitoring cardiac output (CO), cardiac index (CI), circulating blood volume (BV) and ICG elimination rate (K-ICG). We measured hemodynamic changes during the perioperative period in patients undergoing digestive surgery to analyze relationships between hemodynamic changes and surgical procedures, blood loss, water balance and SIRS. METHODOLOGY: Eighty-seven patients who underwent gastrectomy (n=46) and colectomy (n=41) without postoperative complications were enrolled in this study. The corresponding data from 15 patients who underwent laparoscopic cholecystectomy were used as controls. CO, CI, BV and K-ICG were measured by PDD before operation, on the first postoperative day (POD 1), POD 3, POD 7 and POD 14. RESULTS: In all patients, CO and CI increased significantly until POD 3 compared with preoperative levels. BV on POD 1 decreased significantly compared to the preoperative level. K-ICG increased significantly until POD 14. Laparoscopic cholecystectomy resulted in less surgical stress than gastrectomy or colectomy as measured by hemodynamic changes. There were minimal differences in hemodynamics between the gastrectomy and colectomy groups. There were significant negative correlations between intraoperative blood loss and the [POD 1: preoperative values] ratios for CO, CI, BV or K-ICG. There was no correlation between changes in water balance from operation to POD 1 and [POD 1: preoperative value] BV ratio. CONCLUSIONS: An increase in CO and decrease in BV were observed at the early operative stage, especially in patients with systemic inflammatory response syndrome (SIRS). Interestingly, hepatic artery flow volume (K-ICG) remained high until POD 14. It is important to minimize intraoperative blood loss, since it markedly affects postoperative hemodynamics.

Abdomen↗
PubMed1991

[Determination of nystatin component composition using HPLC and TLC with densitometry].

The component composition of nystatin produced by an improved strain of Streptomyces noursei was determined by HPLC on Milichrom chromatograph (USSR). It was shown that the antibiotic consisted of nystatins A1, A2, A3 and B and admixture substances. The data appeared to be in good agreement with the results of the complex TLC investigation, by using densitometry. The component composition of the samples was evidenced by SIEAP mass spectrometry. Physiochemical and biological characteristics of separate components are presented.

Chromatography, High Pressure Liquid↗
PubMed1991

[Identification of Schisardra by TLC-densitometry].

This paper deals with the determination of the lignins in 10 species of Schisandra crude drugs by TLC-densitometry. The result shows that all the 10 species are unidentical in the lignin constituents; the same species vary in the contents with habitats; and the TLC chromatograms of the 10 species differ distinctly from each other.

Chromatography, Thin Layer↗
PubMed1991

Osteoporosis. Current techniques and recent developments in quantitative bone densitometry.

Knowledge about the proper use and interpretation of bone densitometry studies and an understanding of appropriate medical interventions are not universal among physicians, nor are instrumentation and technical performance of bone density studies of uniformly high quality. Indeed, this deficiency of medical and technical expertise is the principal deterrent to widespread implementation of our recommended clinical applications at this time. Nonetheless, given the current impetus to disseminate information about osteoporosis, to make newer instrumentation more readily available, and to limit the cost of these techniques, we anticipate that our recommendations may soon become standard medical practice.

Absorptiometry, Photon↗
PubMed1990

The prediction of serum IgG levels by scanning densitometry.

A novel approach has been described. In this method the serum IgG level can be predicted with a fair degree of accuracy by scanning densitometry and total serum protein values. This approach might be useful as a screening procedure for hypogammaglobulinemia.

Agammaglobulinemia↗
PubMed1990

[Determination of the main alkaloids in wu tou (aconite) by TLC-densitometry].

A method of TLC densitometry was established in order to determine the main alkaloids: mesaconitine, aconitine and hypaconitine in Aconite root. The powdered sample was alkalinized by ammonia and macerated with ether for 24 h. The mixture was then centrifuged, the residue was washed three times each with 2 ml of fresh ether, the combined ether extract was evaporated to dryness and then dissolved in 1 ml of dichloromethane. Standard solution and sample solution were spotted on a sillca gel GF254 plate, and developed with cyclohexane-ethyl acetate-diethylamine (8:1:1), the chromatogram was observed under UV light as dark spots. A Shimazu TLC model 910 was used for scanning at lambda s 236 nm and lambda R 350 nm by reflection mode. Linear calibration curves were obtained for the 3 constituents in the range of 2-6 micrograms. The average recoveries of masaconitine, aconitine and hypaconitine were 97.3, 96.4, 99.1% and the variation coefficients were 1.81, 1.72, 1.18%, respectively. The spots were stable for more than 24 h. Samples from various sources were analyzed.

Aconitine↗
PubMed1990

[Determination of the active ingredients in Chinese drug wuweizi (Schisandra chinensis) by TLC-densitometry].

A method of TLC densitometry was developed to determine the active ingredients (Wuweizisu A, B, C; Wuweizichun A, B; Wuweizi ester and schisanhenol) in Schisandra kernels. The samples were extracted with hexane (3 X 5 ml) for 8, 4 and 4 h respectively. The hexane extract was evaporated to dryness and then dissolved in 1 ml of methanol. Standard solutions and sample solutions were spotted on a silica gel GF254 plate, and developed with toluene-ethyl acetate (9:1) for 18 cm (for Wuweizisu A, B, C) and with toluene-ethyl acetate (4:6) for 18 cm (for Wuweizichun A, B, Wuweizi ester and schisanhenol). On examining the chromatogram under UV light the ingredients appeared as dark spots. A Shimadzu TLC model 910 was used for scanning at lambda s 260 nm and lambda R 350 nm by reflection mode. Linear calibration curves were obtained for the 7 constituents in the range of 1-5 micrograms. The average recoveries of the 7 constituents were 92.4-101.6%; the variation coefficients were 1.62-5.28%. The spots were stable for more than 24 h. This method is sufficiently simple, rapid and accurate for routine analysis.

Chromatography, Thin Layer↗
PubMed1990

Application of dynamic computed tomography scan and computed tomography densitometry in the evaluation of brain volume enlargement.

Cats with brain cold injury and epidural balloon compression with sudden decompression were used as models of vasogenic or ischemic edema and vasoparalysis of the brain vessels. Dynamic CT scan and CT densitometric studies were performed to diagnose and differentiate between brain edema and vasoparalytic changes. The CT methods were found to be useful in CBF and edema zone estimation. The correlation of CT scan and CT densitometry enabled us to evaluate the degree of autoregulation disorders and can be also applied in clinical investigations.

Blood-Brain Barrier↗