High-performance liquid chromatographic determination of fentanyl citrate in a parenteral dosage form.
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Chromatography, High Pressure Liquid↗
Biomedical subjects
T D Wilson
Publications and source records attributed to T D Wilson.
The effect of column age on system suitability parameters for an HPLC assay of bitolterol mesylate aerosols.
A reversed-phase ion-pairing HPLC method is developed for bitolterol mesylate (Tornalate, Winthrop-Breon) in aerosol dosage forms. Using data acquired by this method during a two-year period, the effect of ODS-3 column age on system suitability parameters is assessed. A BASIC program is used to calculate the resolution factor between bitolterol and colterol triester, capacity factors, number of theoretical plates, and tailing factors in studies that followed the performance of one column during this time period and five columns of different ages under normal usage. A 15 to 30% reduction in column performance per year is found.
Aerosols↗
High-performance liquid chromatographic determination of Tornalate in solution dosage forms; a specificity study.
A reversed-phase high-performance liquid chromatographic method has been applied utilizing ion-pairing to measure Tornalate in solution dosage forms. Specificity of the method was demonstrated by selectivity for Tornalate analysis, analysis of stressed samples and by peak homogeneity tests. These included the diode-array derived spectral overlay test and fraction collection with rechromatography in an alternate normal phase system. Linearity was also demonstrated in terms of recovery from synthetic samples and detector response.
Chromatography, High Pressure Liquid↗
Stability of milrinone in 0.45% sodium chloride, 0.9% sodium chloride, or 5% dextrose injections.
The stability of milrinone in 0.45% and 0.9% sodium chloride injections and in 5% dextrose injection in glass and plastic containers was studied. Admixtures containing milrinone 0.2 mg/mL were prepared in three 500-mL glass containers, three 500-mL polyethylpolypropyl copolymer plastic containers, and three 1-L flexible plastic containers of each solution. Milrinone content was determined by high-performance liquid chromatography at intervals during 72 hours of storage at room temperature; one sample of each solution and container type was protected from light. Duplicate assays of each sample were performed, and samples were observed for visual and pH changes. In all samples milrinone concentrations were more than 97% of the initial concentration. No changes in pH or appearance occurred. Milrinone at a concentration of 0.2 mg/mL is stable for 72 hours at room temperature in 0.45% and 0.9% sodium chloride injections and in 5% dextrose injection in glass or plastic containers.
Chromatography, High Pressure Liquid↗
Clinical competence of paediatric primary health care nurses in Soweto.
Primary health care (PHC) nurses provide care at polyclinics in Soweto. Our study assessed nurse competence in the clinical detection of important respiratory signs in 337 consecutive paediatric patients with respiratory complaints. The patients were then independently re-examined by two paediatricians, one of whom was arbitrarily chosen as a 'standard doctor'. The standard doctor found 95 patients with important respiratory signs; nurses detected the same signs in 45 and the other doctor in 44 patients. Therefore nurses detected important signs as well as could be expected, considering the inter-observer variation between doctors. The nurses did, however, significantly overdiagnose one condition, follicular tonsillitis. Our results suggest that the Soweto paediatric PHC nurses detect clinical signs with as much accuracy as doctors. This study adds to the available evidence that adequately trained and supervised nurse practitioners can provide high-quality health care.
Clinical Competence↗
Simultaneous liquid chromatographic determination of glutaric acid, phenylephrine, and benzyl alcohol in a prototype nasal spray with application to di- and tricarboxylic acids.
A rapid reversed-phase high-performance liquid chromatographic method for the simultaneous determination of glutaric acid, phenylephrine, and benzyl alcohol in nasal spray has been developed. UV detection was utilized at 210 nm for the assay of glutaric acid and phenylephrine with an adjustment to 254 nm for the measurement of benzyl alcohol. Linearity and recovery data were obtained for each component in spiked placebo studies. An investigation of the retention mechanisms of the three components showed that phenylephrine was retained by ion-pairing with octanesulfonate anion while glutaric acid and benzyl alcohol partitioned as a suppressed ion and a neutral molecule, respectively. The method has been further extended to the reversed-phase separation of di- and tricarboxylic acids using a totally aqueous 0.0074 M phosphoric acid mobile phase. The retention of these acids was related to their octanol-water partition coefficients and structural variation.
Aerosols↗
Structural influences on the amperometric detection of opiates in high-performance liquid chromatography.
The oxidation reactions of a series of opiates occurring at a glassy-carbon electrode in amperometric high-performance liquid chromatographic detection has been investigated. A structure-reactivity correlation has been drawn for morphone, morphinan and benzomorphan derivatives. Polarography and hydrodynamic voltammography were used to show the importance of phenolic groups to this reaction. Acyl substitution on the phenol did not prevent amperometric detection.
Chemical Phenomena↗
Tuberculosis management in Soweto.
Despite the availability of highly effective therapy, tuberculosis (TB) remains a major problem in South Africa, even in urban centres such as Soweto which is relatively well provided with health services. We therefore assessed two aspects of TB management in Soweto: (i) the proportion of known tuberculous patients adequately treated; (ii) whether case finding through investigation of home contacts of notified patients was effective. In 1978 patients with TB were required to take chemotherapy for at least a year. Only 28% of newly notified patients attended the clinics frequently enough and/or were hospitalized long enough to obtain 80% or more of the treatment they required during that first year. A major part of this problem of non-compliance was infrequent attendance; these patients received therapy of an adequate duration, but at an inadequate dosage. At least 17% of patients over 10 years of age had tubercle bacilli in their sputa on microscopy more than 4 months after therapy was started. About two-thirds of known home contacts were investigated by the health services in accordance with their stated policy, and 5% of contacts were subsequently notified. Home-contact tracing therefore seems worthwhile.
Adolescent↗
High-performance liquid chromatographic-amperometric determination of naloxone hydrochloride injection.
Naloxone hydrochloride has been measured in the injectable dosage form at 0.4 and 0.02 mg/ml using high-performance liquid chromatography with amperometric detection. This method was contrasted with an ultraviolet detection method at 229 nm and found to provide comparable recovery and linearity results. At the electrochemical detection limit of 0.1 ng injected a signal-to-noise ratio of 10.4 was found.
Chromatography, High Pressure Liquid↗
Why don't patients return for antihypertensive treatment in Soweto?
Out of an inception cohort of 91 newly treated hypertensive patients at a Soweto polyclinic only 16 (18%) attended regularly during the year after their first visit. Visits were made to the homes of the 75 non-compliant patients between 18 and 21 months after the patient's first visit to establish the reasons for non-attendance. Five of the 75 (7%) had died, 16 (21%) were not available for an interview and 54 (72%) were interviewed. These 54 patients gave many different reasons for not returning regularly. The most common reasons were: (i) they did not remember being told that they had hypertension and that they needed to return for more treatment--14 patients; (ii) they had been away from Soweto--7 patients; (iii) they had been unable to take time off work--6 patients; (iv) they considered themselves to be regular attenders--5 patients; (v) they had not felt ill--5 patients; and (vi) they experienced unwanted side-effects--4 patients. Only 2 patients said that they had received regular treatment elsewhere. In the light of these results different approaches designed to improve both attendance and medication compliance are being developed and evaluated.
Aged↗
Queueing and patient flow at a Soweto polyclinic.
We studied all 265 adult patients who came to a Soweto polyclinic on 18 March 1980. The objectives were: (i) to determine the flow of patients and the time spent in the polyclinic; (ii) to use computer models to predict the effects of altering numbers of staff and/or the introduction of an appointment system; and (iii) to elicit information relating to the feasibility of introducing an appointment system. The results show that of the 265 patients, 80% arrived before 10h00 and 1% arrived after 13h00. Forty-one per cent of these patients waited in 5 or more queues. Of the 245 patients for whom the amount of time spent in the clinic was available the mean time spent in the clinic was 171 minutes, with a range of 16 - 375 minutes. The mean time spent receiving attention was 24 minutes. IBM's GPSS/360 programme was not found to be useful for running computer-simulated flow models. Of 241 patients who returned questionnaires, 65% said they would like the introduction of an appointment system and 70% would be able to make appointments relatively easily. An appointment system might considerably reduce time being wasted. The practicalities of such a system in terms of the functioning of the clinic must still be carefully investigated. We suggest that a feasible appointment system be introduced and its effect on patient satisfaction and flow carefully monitored.
Appointments and Schedules↗
Hypertension management and patient compliance at a Soweto polyclinic.
The aim of our study was to assess the quality of hypertension detection and management at the Senaoane polyclinic for Black patients in Soweto and to determine the degree of patient compliance with antihypertensive drug treatment. We reviewed the records of 2,200 consecutive new patients who were 15 years of age or older. The blood pressures of 84% of the patients were measured at their first visit to the polyclinic. Of the patients seen initially by primary health care nurses, 98% were managed correctly according to the blood pressure management protocol that these nurses had been trained to use. Of 55 patients started on antihypertensive drug treatment at their first visit to the polyclinic, 31% did not visit the polyclinic again during the next year. Only 15 patients (27%) were compliant, i.e. they attended often enough during the following year to allow them to receive 80% or more of the necessary drugs. These 15 patients had substantial reductions in their diastolic blood pressures (mean reduction 21 mmHg). We regard poor compliance as the major factor preventing the polyclinic from reducing morbidity and mortality in hypertensives. Strategies for improving compliance need to be developed and evaluated for different poor compliance groups. These groups can be defined according to the severity of the hypertension and the pattern of poor compliance ("early drop-outs' v. "irregular attenders').
Adolescent↗
HPLC analysis of underivatized fatty acids in margarines.
The composition of the underivatized fatty acids in margarines was determined by high performance liquid chromatography (HPLC). A 50-min analysis gave not only the distribution of the cis- and trans-isomers of the 18 carbon-length, but also a quantitative measure of seven of the underivatized fatty acids studied. High concentrations of the essential fatty acid, linoleic acid, were found in the four margarine samples. Results of the quantitation, reproducability of the HPLC analysis, and stability of the standards are discussed. It was found that the developed HPLC analysis was able to adequately separate the geometric isomers, linoleic acid (18:2 delta 9c, 12c) from linolelaidic acid (18:2 delta 9t, 12t). However, a mixture of the other two isomers, 18:2 delta 9c, 12t and 18:2 delta 9c, 12c coeluted together between the peaks due to the 18:2 delta 9c, 12c and 18:2 delta 9t, 12t isomers. This study did not attempt to separate the various positional isomers of underivatized fatty acids.
Chromatography, High Pressure Liquid↗
Fibroma in the abdomen of a horse.
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Abdominal Neoplasms↗
High-performance liquid chromatographic determination of hydrocortisone cypionate: method development and characterization of chromatographic behavior.
A reversed-phase high-performance liquid chromatographic method for hydrocortisone cypionate bulk drug and oral solution was developed that avoids the use of a heated column as described in USP XX. A study of the effect of the organic modifier concentration on the capacity factor suggests that mixed partition and adsorption phenomena are responsible for the retention of several steroids when acetonitrile is used in the mobile phase. Evidence is presented that hydrogen bonding of the solute molecule with silane hydroxyl groups may be responsible for the adsorption.
Chromatography, High Pressure Liquid↗
Hypercalcitoninism without hypercalcitoninemia.
Yearling heifers overfed protein, calcium and phosphorus with a feed recommended for high producing dairy cows developed osteopetrosis and skeletal malformations as a result of retarded bone resorption. Histologic and electron microscopic examinations showed that C cell hyperplasia was also present. The presence of C cell hyperplasia and osteopetrosis supported the diagnosis of hypercalcitoninism. Clinically unaffected heifers were studied by serum chemistry after 1 to 1.5 months on the same diet at age 6 months and after 3 months on an optimal diet to learn whether they showed evidence of hypercalcitoninism as expressed by retarded bone resorption and/or hypercalcitoninemia. The data indicated that bone resorption was retarded and that serum gastrin was elevated in the heifers without skeletal malformations while on the high calcium feed. The heifers were isocalcitoninemic. The data suggested that overfeeding calcium was sufficient to produce hypercalcitoninism but the rate of calcitonin secretion had not exceeded the rate of removal of calcitonin from blood by binding to tissue receptors and by metabolic degradation. Since calcitonin is rapidly removed from blood, hypercalcitoninism may occur without concomitant hypercalcitoninemia.
Animal Feed↗
High performance liquid chromatographic determination of amino acids in the picomole range.
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Amino Acids↗
The extended role of the nurse.
The improvement of the quality and quantity of primary health care is a major issue in southern Africa. The role of the nurse in the delivery of this care was examined at a workshop conference on 'The extended role of the nurse'. In this article in the conclusions of the conference are reported, and the problems identified in extending the role of the nurse in this field are discussed.
Africa, Southern↗