Human experience in space.
Dr. Carr recounts his own experience in space on the Skylab III mission. He notes that medical research in space continues today, and compares current Shuttle missions with those of Skylab.
Dermatology↗
Biomedical subjects
G P Carr
Publications and source records attributed to G P Carr.
Evaluation of a photodiode array detector for the verification of peak-homogeneity in high-performance liquid chromatography.
Photodiode array liquid chromatography detectors are claimed to have the ability of evaluating the homogeneity of chromatographic peaks and this could provide a very powerful tool in support of method development. However, in pharmaceutical analysis, for this to be of practical value it must be capable of detecting inhomogeneities at low levels. In this paper, a test has been devised to challenge the sensitivity of instruments to this application. The test makes use of mixtures of the similar benzodiazepines temazepam and lormetazepam in a chromatographic system which does not separate them. One instrument has demonstrated the ability to detect levels of just 0.5% w/w of one benzodiazepine in the other. Statistical F-tests and t-tests have been used to demonstrate that non-homogeneities have been detected with a high level of confidence. It is concluded that photodiode array detectors have the potential to evaluate the homogeneity of chromatographic peaks with a high degree of sensitivity. However, most instruments do not realize this potential because their software does not make proper use of all the data available.
Chromatography, High Pressure Liquid↗
A practical approach to method validation in pharmaceutical analysis.
Guidelines issued by Regulatory Authorities make it clear that validation of analytical methodology is now widely required in support of registration dossiers. Although some attempts are made at defining terms and some vague indications are sometimes provided within these guidelines, no clear advice is provided on how validations should be conducted and what results should be expected. In this paper it is attempted to suggest some practical approaches to conducting validation and in particular to the determination of accuracy, linearity and limit of detection/quantitation.
Chemical Phenomena↗
Chromatographic system suitability tests--what should we be using?
System suitability tests are applied to chromatographic analytical methods to confirm the methods' continuing suitability for use on different occasions following their initial validation. The paper discusses the checks and controls which have traditionally been applied, questions their appropriateness and makes recommendations for others that should be considered.
Chemistry, Pharmaceutical↗
Pharmacopoeial procedure for the determination of tylosin factors by high-performance liquid chromatography.
A method is described for the determination of the factors in tylosin base and tylosin tartrate as raw materials and in dosage forms. The reversed-phase chromatographic system is compared with other similar systems in terms of selectivity towards the major tylosin factors and an aldol condensation degradation product observed in tylosin injection. Experimental conditions affecting the separation of the components are discussed, together with procedures to demonstrate system validity. It is considered that the methods developed provide appropriate procedures for inclusion in pharmacopoeial monographs for tylosin, tylosin tartrate, tylosin premix, tylosin soluble powder, tylosin tablets and tylosin injection.
Chromatography, High Pressure Liquid↗
The development of British pharmacopoeia monographs for idoxuridine and idoxuridine eye drops using high-pressure liquid chromatography for assay and for controlling related impurities.
The monograph published in the 1973 edition of the British Pharmacopoeia (BP) for idoxuridine required revision because it contained a non-specific assay and no tests for related impurities. It was also necessary to prepare a new monograph for idoxuridine eye drops. The Japanese Pharmacopoeia contains a thin-layer chromatographic test for impurities but this was not considered ideal. Improved thin-layer chromatographic tests were sought but when this was unsuccessful, methods using high-pressure liquid chromatography were examined. A system using reversed-phase chromatography was selected for inclusion in BP Addendum 1977 since it provided a specific assay method and limit test for related impurities which could be applied to both the drug substance and the eye drops.
Chromatography↗