The stability of benzoyl peroxide by isothermal microcalorimetry.

Isothermal microcalorimetry may be used to determine kinetic and thermodynamic parameters for chemical reactions. This paper reports rate constants, determined as a function of temperature, and the activation enthalpy for the degradation of solid benzoyl peroxide as determined by isothermal microcalorimetry. Studies were conducted on aqueous suspension phase, solid benzoyl peroxide. In addition, supporting evidence is cited from work carried out in this laboratory on the solution phase degradation of benzoyl peroxide using UV-visible spectrophotometry. The activation energy obtained by microcalorimetry was E(a)=137.8+/-6.6 kJ mol(-1) and the activation energy obtained from UV-visible spectrophotometry was E(a)=112.7+/-4.2 kJ mol(-1).

The stability of benzoyl peroxide formulations determined from isothermal microcalorimetric studies.

Recent developments in the analysis of microcalorimetric data output allow the possibility of determining both thermodynamic and kinetic parameters for complex reaction systems. Such experiments routinely take around 50 h, hence qualifying for the description rapid. The methods have earlier been applied to a study of the stability of benzoyl peroxide itself in aqueous suspension. This paper reports the results of isothermal microcalorimetric study of the stability of benzoyl peroxide in the presence of a wide range of excipients and in formulated materials. The results are shown to assist in formulation design, are achieved rapidly and are derived from direct experimental study of the complex systems themselves. That is, no ancillary information is required nor are the studies invasive or destructive.

The impact of a health screening flow sheet on the performance and documentation of health screening procedures.

We monitored physician performance of stool occult blood testing and breast exams during health maintenance visits of patients aged 50 or greater, to assess the impact of a physician education program and the use of a health screening flow sheet on performance of these health screening procedures. During the baseline study period, use of these procedures was documented for only about 40% of patients. A physician education program (conferences reviewing appropriate health maintenance screening procedures, and information on the use of a specific health screening flow sheet) did not significantly change the rate of documented physician performance of these procedures. After a health screening flow sheet was introduced into the medical record, the rate of documented performance of these screening tests increased. However, despite the presence of the screening flow sheet in the patient record, most screening evaluations were documented only in the progress notes. These results suggest that the screening flow sheet serves primarily as a memory prompting device. The usefulness of the flow sheet as a patient data storage device appears questionable.

MMPI identification of nonrehabilitants among disabled veterans.

Utilized the Minnesota Multiphasic Personality Inventory (MMPI) with IQ scores and selected biographic data to identify drop-outs in a Veterans Administration vocational rehabilitation program. Subjects were 61 male disabled veterans. Data were collected at VA Hospital Richmond, Virginia, between September 1973 and September 1974. Follow-up six months after entrance into training utilized persistence in training or employment as success criteria. Multivariate analysis identified 32 of 33 successful and 25 of 28 unsuccessful subjects with p less than .001. Factor analysis of the best predictors identified MMPI Psychopathic deviate (Pd) Hypomania (Ma), and Lie (L) scales which was interpreted to be a social adjustment factor. Four other factors were identified. Results indicated the MMPI was a useful instrument in the identification of disabled veterans who were likely to experience difficulty in post-hospital vocational rehabilitation.