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Biomedical subjects

J W Levchuk

Publications and source records attributed to J W Levchuk.

9 recordsLinked to original sources
PubMed1994

Ability of laboratory methods to predict in-use efficacy of antimicrobial preservatives in an experimental cosmetic.

The abilities of nine antimicrobial systems to preserve an experimental water-based cosmetic formulation were evaluated by six microbiological challenge tests: the U.S. Pharmacopeia test; the British Pharmacopeia test; the Cosmetic, Toiletry, and Fragrance Association test; the rapid screen test; the sequential challenge test; and the post-use test. The antimicrobial systems contained various combinations and amounts of two parabens and a quaternary compound in order to provide a broad range of preservation. The results obtained were compared with the abilities of the formulations to support maintenance and growth of microorganisms in microfloras obtained from human axilla areas and finger skin during an 8-week simulated in-use test. Without statistical analysis all of the tests predicted the results obtained with well-preserved or poorly preserved formulations. The rapid screen test was the best test for predicting differences at intermediate levels of preservation. Statistically, all of the tests were equivalent predictors of preservation efficacy in the in-use test (P = 0.05). At the P = 0.10 level, only the U.S. Pharmacopeia, British Pharmacopeia, rapid screen, Cosmetic, Toiletry, and Fragrance Association tests were significantly predictive. The results of prediction by a test, based on the preservative levels used, agreed well with the in-use test results (P = 0.01). A total of 20% of the formulations that contained excessive microbial levels contained human axilla microorganisms. The levels of preservation in failed products were similar to the levels of preservation in unused controls.

Axilla↗
PubMed1988

Method for testing the sterility of total nutrient admixtures.

A test for determining the sterility of a total nutrient admixture (TNA) containing equal quantities of 10% fat emulsion (Liposyn II), 8.5% amino acids injection, and 50% dextrose injection using the USP membrane filtration procedure was developed and evaluated. Membrane filter selection was determined by analysis of flow rates, membrane fluid compatibility, bubble point stability, and rinse fluid requirements. Microbial challenges employing five organisms (Bacillus subtilis, Escherichia coli, Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa) and both soybean casein digest and fluid thioglycollate media were used to confirm the ability of the test to detect low-level microbial contamination. A polyvinylidene fluoride membrane was determined to be the most appropriate of the membrane types studied because of its superior flow rate and membrane-fluid compatibility. Bubble point testing revealed no detrimental effects on the membrane. The potential problem of haziness caused by retention of the TNA by the membrane with subsequent release in the culture media (which could result in false-positive growth determinations) was diminished by using a sterile 0.1% peptone solution rinse and careful observation techniques. Performance of the sterility test by six hospital pharmacists required an average of 14.2 minutes. Sterility testing of alternate TNAs compounded with Intralipid and Nutralipid was not feasible because of prolonged filtration times. The basic USP membrane filtration procedure for large-volume injections can be used by hospital pharmacists for testing the sterility of TNAs. When fat emulsions are used in compounding, sterility-testing procedures specific to the emulsion product used should be developed and evaluated.

Culture Media↗
PubMed1984

Special considerations in the use of vertical laminar-flow workbenches.

The design, operation, and proper use of vertical laminar-flow workbenches are reviewed. Vertical-flow hoods are different from horizontal-flow units in several important ways that must be considered by operators who may have been trained to use the horizontal-flow type. Air in vertical-flow units provides practically no resistance to ingress of air propelled by body motions of the operator or passers-by or from nearby ventilation ducts. The HEPA-filtered air hits the work surface perpendicularly and must travel horizontally to reach the exhaust ducts; thus, manipulations should not be performed close to the work surface. Turbulence patterns around objects in the vertical flow hood will be different from that in horizontal-flow units. Manipulative technique is also different in a vertical-flow hood. Supplies may be arranged to the sides and the back of the area in which manipulations will be performed. Items not sterile, including fingers and hands, must be kept downstream from critical sites. Masks do not have to be worn because of the hood's glass panel. Operators must be cognizant of basic differences between vertical- and horizontal-flow hoods.

Drug Compounding↗
PubMed1983

Self-directed learning of hospital pharmacy residents in western Canada.

The extent of self-directed learning among hospital pharmacy residents in western Canada was studied. A preresidency questionnaire and a postresidency group interview with a set of questionnaires were used. The residents were asked to list learning projects conducted in their residency programs; these learning projects were categorized as self-directed, mutual-agreement, and preceptor-directed. A postinterview questionnaire was used to obtain postresidency measurements of self-directedness and resident autonomy. Twenty-four residents provided data on 164 learning projects. Projects with the most meaningfulness, high achievement contribution, positive motivation, and relevance corresponded with the self-directed approach. Residents who had more meaningful learning entered their residencies with no more self-directedness than other residents, but they did have more autonomy in their residencies. No particular type of project, with respect to learner autonomy, was found to be more problematic than the others. Facilitation of learner autonomy in a hospital pharmacy residency may increase the value of self-directed learning projects in general and improve the resident's self-directedness. Self-directed learning should continue to be part of residency programs.

Canada↗
PubMedDate not supplied

Training for GMPs.

Training is a dynamic process to assure that personnel are capable of performing their assigned functions. CGMP regulations contain only general expectations, and no FDA guideline regarding training has been issued. Training programs are generally in place in pharmaceutical firms. However, training quality and effectiveness may be inadequate in a number of firms. A pharmaceutical firm should be able to show that its training program consistently meets its training goals as purported, and that each trainee completing an instructional module has acquired the competencies as purported. The proper application of sound principles of instructional design should help firms overcome GMP deficiencies regarding training and personnel qualification. For example, principles of mastery learning, competency-based instruction, performance objectives, a systems approach to instructional design, and the evaluation of instruction as well as the instructional program should help ensure meaningful, relevant training and appropriate, effective instruction. Review of training should be included in the firm's program for managing change. Firms should also ensure adequate training documentation, a positive attitude toward training, and that training is not used inappropriately to remedy performance deviations not resulting from skills deficiencies.

Drug Industry↗
PubMedDate not supplied

Good manufacturing practices and clinical supplies.

Quality characteristics must be assured through adherence to good manufacturing practices in the production, control, and testing of drug products intended for investigational as well as commercial use. A draft guideline on the preparation of investigational new drug products, soon to be available in final form, addresses questions that have been raised regarding acceptable practices and procedures to facilitate compliance with the CGMP regulations as applied to clinical supplies. Inspections of sterile clinical supplies production can be expected to include the areas most likely to influence product safety, quality, and uniformity in the same manner as would be expected regarding the manufacture of commercial batches. Some areas of particular significance in the manufacture of parenteral clinical supplies include validation of terminal sterilization, aseptic processing, and oxygen exclusion. The validation of the aseptic handling during lyophilization requires special attention. Other CGMP concerns include the provision of a quality control unit, avoiding packaging mixups, and being prepared for an amendment to the CGMP regulations regarding terminal sterilization.

Drugs, Investigational↗