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Biomedical subjects

J L Ford

Publications and source records attributed to J L Ford.

At least 55 records · Page 3Linked to original sources
PubMed1992

Bacterial retention properties of heat and moisture exchange filters.

We have examined the properties of six heat and moisture exchange filters (HMEF) to ascertain their resistance to liquid flow and their ability to retain a challenge bacterium, Pseudomonas diminuta, from aqueous and nebulized suspensions. Only one HMEF, the Pall Ultipor was able to withstand a significantly greater pressure of liquid than that found in clinical practice. However, when breached, the HMEF were unable to prevent transmission of micro-organisms from aqueous suspension. Only the Darex Hydrobac filter failed to meet the manufacturer's claim for filter efficiency for nebulized bacteria, mainly because the filter housing failed under test. When the reduction in bacterial cells after passage of the nebulized Pseudomonas diminuta through the HMEFs was analysed statistically, the data showed that the HMEF produced by Pall (Ultipor) and Intersurgical (Filter therm) were superior to those produced by DAR Mediplan (Hygrobac), Intertech (HME 225-2835-800) and Gibeck (Humid-vent).

Aerosols↗
PubMed1986

A note on the recovery of micro-organisms from an oil-in-water cream.

The isolation of micro-organisms from the oil-in-water Aqueous Cream BP, has been examined using a variety of solvent systems to disperse the cream prior to membrane filtration or direct inoculation. Pour-plate methods which utilize combinations of either peptone-water (containing 5% w/v polysorbate 80) or nutrient broth (containing 4% w/v Lubrol W) provided the most efficient recovery of Pseudomonas aeruginosa but still allowed less than 20% recovery. White spirit and isopropyl myristate allowed no recovery when used as dispersants. Recoveries of P. aeruginosa varied according to the source of the cream. A combination of 1% w/v polysorbate 80 in 0.1% w/v peptone-water and membrane filtration allowed 63.2% w/v and 67.0% w/v recoveries respectively of Aspergillus niger and Candida albicans from unpreserved aqueous cream, but gave unreproducible results for Escherichia coli and P. aeruginosa. Chlorocresol 0.1% w/v) did not meet the British Pharmacopoeial requirements for efficacy of antimicrobial preservatives when tested against C. albicans using membrane filtration to isolate the micro-organism.

Aspergillus niger↗
PubMed1985

A note on the contamination of eye-drops following use by hospital out-patients.

Examination of 273 eye-drops, returned to a hospital pharmacy by out-patients showed that 27% were contaminated. Common contaminants included Bacillus spp, Staphylococcus albus and Sarcina spp. Those eye-drops containing the preservatives chlorbutol or thiomersal showed above average levels of contamination, thus questioning the suitability of these preservatives for ophthalmic preparations.

Bacteria↗
PubMed1985

Similarities in the release rates of different drugs from polyethylene glycol 6000 solid dispersions.

The dissolution rates (mg min-1) of 10 drugs, solid dispersed by fusion in polyethylene glycol 6000 (PEG 6000) have been examined by rotating disc methodology. The dispersions generally displayed release rates which were linearly dependent upon the drug concentration (% drug) at high polymer content. However the range over which this linearity was encountered varied unduly, e.g. 0-2% for phenylbutazone and 0-15% for paracetamol. The slope of this line (mean value: 0.451 mg min-1 % -1) was statistically the same for nine of the drugs studied, the exception being griseofulvin which did not form a true solid dispersion but was a microcrystalline dispersion of the drug within the PEG. During fusion, chain scission of the PEG 6000 occurred in the presence of several drugs. PEG 6000 was incompatible with disulfiram, frusemide, chlorothiazide and chlorpropamide.

Chemistry, Pharmaceutical↗
PubMed1984

The effect of incorporation of indomethacin with polyethylene glycol 6000 in a solid dispersion on its in vivo properties in the rat.

Preparations of indomethacin and indomethacin in combination with PEG 6000 were administered in solid form by the oral route to male rats. No significant differences in anti-oedema activity were observed between the different preparations of indomethacin, but high blood levels of drug were observed following dosing with indomethacin, in a PEG 6000 melt. Rapid dispersion formulations of indomethacin were also found to be gastro-toxic.

Animals↗
PubMed1979

The assay and stability of chlorpropamide in solid dispersion with urea.

Thin layer chromatography followed by reflectance densitometry has been used to evaluate the stability of chlorpropamide-urea during the fusion process. Urea was found to decompose to biuret and chlorpropamide to p-chlorobenzenesulphonamide: several other unidentified decomposition products were detected. The energy for decomposition of chlorpropamide was 57.1 kJmol-1 for melts containing 15 and 30% chlorpropamide. Decomposition followed apparent first order kinetics.

Chlorpropamide↗