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Biomedical subjects

M C Allwood

Publications and source records attributed to M C Allwood.

At least 19 recordsLinked to original sources
PubMed1994

Practical guides. I: Central intravenous additive services.

Centralized intravenous additive services (CIVA) are becoming an essential component of hospital pharmacy services in the U.K. This review explores the background to their development, indicating how aseptic services commenced with total parenteral nutrition, developed further with cytotoxic drug preparation and is now progressing, in an increasing number of hospitals, to a full range of parenteral drug services. The benefits of pharmacy-operated provision of injections in ready-to-administer forms are described. The operation of such services is then considered in detail. A brief discussion of the types of service that can be operated is followed by consideration of staffing, facilities, methods of operation, technical support and documentation. National guidelines in the U.K. and U.S.A. are compared, since these have a major influence of the nature of CIVA service operation. The issues associated with the stability of reconstituted and repackaged injectables are discussed, together with how our knowledge can be used in the assignment of shelf lives to pharmacy-prepared intravenous additives. The review concludes with a brief assessment of future trends and changes likely to affect intravenous services provided under pharmacy control.

Dosage Forms↗
PubMed1992

Assessment of trace element compatibility in total parenteral nutrition infusions.

The application of X-ray energy dispersive spectroscopy to detect elements collected from TPN mixtures on membrane filters has been investigated. Many simple total parenteral nutrition mixtures prepared aseptically in large bags can be stored for extended periods. Trace elements are normally excluded from such bags, because not enough is known about their long-term stability and compatibility in total parenteral nutrition mixtures. Assessing the compatibility of many trace elements by conventional methods that rely on detecting concentration changes is extremely difficult. Analysis of precipitates from total parenteral nutrition mixtures confirmed that the proposed method was capable of identifying a number of elements from the mixture in complex precipitates, including calcium, phosphorus, iron, copper and selenium.

Electron Probe Microanalysis↗
PubMed1991

The stability of four catecholamines in 5% glucose infusions.

The stability of adrenaline, noradrenaline, dopamine and dobutamine in 5% glucose infusion minibags stored at 5 degrees C was determined. Results indicated that noradrenaline (16 and 40 mg/l) and dobutamine (1 and 5 g/l) were relatively stable with t/95% values in excess of 30 days. Adrenaline and dopamine were less stable. The t/95% values were approximately 20 and 14 days respectively.

Catecholamines↗
PubMed1990

BIPP--how does it work?

The antibacterial activity of BIPP and its constituents against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was measured by growth inhibition tests. BIPP was found to have negligible antibacterial activity. In addition, no release of iodine from BIPP was detected over a 4-week period. It is proposed that much of the evident antibacterial activity of BIPP may be a reflection of the meticulous surgical debridement that accompanies its use. In addition, BIPP makes the impregnated gauze impervious to blood and body fluids ensuring little nutrition for bacteria to thrive in its interstices.

Anti-Infective Agents, Local↗
PubMed1990

Effect of ciprofloxacin on the pharmacokinetics of antipyrine in healthy volunteers.

The pharmacokinetics of antipyrine was studied in six healthy male volunteers before and during a 6-day course of 750 mg oral ciprofloxacin b.d. Antipyrine clearance was significantly decreased and the half-life significantly prolonged (P less than 0.05) during ciprofloxacin treatment. No significant difference in the apparent volume of distribution of antipyrine was observed. The results of this study suggest that ciprofloxacin is a potent inhibitor of hepatic drug metabolism.

Adult↗
PubMed1987

The compatibility of calcium phosphate in paediatric TPN infusions.

The addition of calcium phosphate to total parenteral nutrition (TPN) infusions is investigated with particular reference to factors affecting the solubility of the salt. Recommendations are made about the most appropriate method for adding calcium phosphate to paediatric and neonatal TPN products.

Calcium Phosphates↗
PubMed1984

Factors influencing the stability of ascorbic acid in total parenteral nutrition infusions.

Ascorbic acid stability in TPN infusions in 3-litre plastic bags was examined. Vitamin C was found to degrade slowly in mixtures which do not contain trace elements. In the presence of copper, degradation proceeds rapidly until dissolved oxygen is depleted. Reducing the copper concentration had only a minor influence on degradation rate. However, this copper-catalyzed reaction was prevented if cysteine was present in the TPN regimen. The amount of ascorbic acid degraded depended on the dissolved oxygen content of the infusion, the amount of residual air in the bag after filling and the permeability of the plastic to oxygen. In the absence of copper, 20-30 mg ascorbic acid was broken down within 24 h at ambient temperatures, but if copper was present, 150-200 mg was degraded within 2-4 h. The contribution of dehydroascorbic acid to the amount of vitamin C delivered to the patient was negligible. It is concluded that either vitamin C and trace element injections containing copper should not be added to the same bag, or an adequate coverage of ascorbic acid must be included to allow for losses by oxidation before and during administration.

Ascorbic Acid↗
PubMed1981

High pressure liquid chromatographic determination of cyclosporin A in plasma.

A sensitive and rapid high performance liquid chromatographic method was developed for the determination of Cyclosporin A in plasma. Cyclosporin A was isolated from methanol-precipitated plasma using miniature compressed silica reverse-phase columns (Sep-Paks). In the method, 1 ml serum is precipitated in 3 ml methanol. After centrifugation 2 ml of supernatant is diluted in 1 ml water and the sample flushed through a washed Sep-Pak. The sample on the miniature column is washed with water and 75% v/v methanol, and Cyclosporin A is eluted in 1 ml methanol. At least 80% of the drug is recovered. Samples are analyzed on a reverse-phase column, the mobile phase is methanol:water (95:5) and detection is conducted at 205 nm. The detection limits were less than 100 ng/ml, but in plasma some interference was observed, especially at concentrations below 1000 ng/ml.

Chromatography, High Pressure Liquid↗
PubMed1977

The potential for contamination of intravenous infusions by airborne skin scales.

Skin scales may be attracted onto the surface of administration set connector needles before insertion into infusion containers. Viable microorganisms associated with skin scales may therefore gain access to the infusion by this route. A technique is described for creating an environment of airborne skin scales. This environment is used to examine the attraction of skin scales onto the surface of administration set connector needles and three other materials. After exposure, skin scales are found adhering to the surface of each material examined. The attraction of skin scales onto administration set connector needles is dependent on the time of exposure to the environment. Results suggest that intravenous infusions can be contaminated by this route when the infusion and administration set is assembled.

Air↗