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Biomedical subjects

L Chafetz

Publications and source records attributed to L Chafetz.

At least 19 recordsLinked to original sources
PubMed1996

The experience of severe mental illness: a life history approach.

In this report, severely mentally ill adults describe their experiences of long-term illness. Forty-three research participants completed Life Chart Interviews covering their personal history since the onset of their psychiatric disorder. Participants appeared to be generally reliable informants on their treatment histories. They indicated that individual learning and personal choices influenced the course of the psychiatric disorder over time, including decisions about use of treatment and environmental support. These results support the value of life-context approach to research on severe mental illness.

Adult↗
PubMed1994

Trace decomposition of selegiline. Use of worst-case kinetics for a stable drug.

A solution of selegiline hydrochloride reference standard, which contained no detectable impurities at the time of its preparation, was found by HPLC to contain a trace of a compound at the locus of methamphetamine when analyzed after 1 year. Heating selegiline solutions at pH 7 and 105 degrees C produced methamphetamine as the major product at a rate which closely followed the first-order rate equation. Using only these data and worst-case assumptions, rate constants were estimated at various temperatures; the activation energy was estimated to be about 25 kcal, and the stability-indicating validity of the assay used was reaffirmed. Selegiline undergoes degradation at a negligibly slow rate.

Chromatography, Gas↗
PubMed1991

Stability of diltiazem in acid solution.

A brief study of the stability of diltiazem was conducted at 70 degrees C in the pH range of 0.45 to 6.1 using polarimetry. Racemization did not occur. The hydrolysis rate of the acetate ester moiety was found to be slow, with a minimum in the pH-rate catenary at approximately pH 3.5. Where reaction products are known, photoelectric polarimetry has great advantages in speed, convenience, and cost compared with chromatographic methods for measuring rates of reaction of optically active analytes.

Diltiazem↗
PubMed1989

Issues in psychiatric caregiving.

This report presents descriptive data from a pilot investigation of 20 family caregivers to the psychiatrically disabled. Data were obtained through focused interviews with caregivers recruited from community organizations and clinical services. The model subject was a middle-aged mother caring for an adult child with schizophrenia. Qualitative analysis of interview data identified major concerns and support needs of individuals who assume this stressful role. Mental health nurses may assist caregivers to obtain support, reduce risks to their own well-being, and to promote well-being of the mentally ill.

Adult↗
PubMed1987

Kinetics of procaterol auto-oxidation in buffered acid solutions.

The kinetics of procaterol (1) degradation in buffered acidic solutions (pH 4-6) was investigated using an HPLC procedure. The effect of temperature and ferric ions on the reaction rate was estimated. In acidic solutions, 1 undergoes pseudo first-order degradation with an induction period. The first-order rate constant for degradation increased and the induction period decreased with an increase in pH. Ferric ions catalyzed the degradation reaction and decreased the induction period. At pH 6, the activation energy of the reaction was 34.5 kcal/mol/deg. The results of this study indicate that 1 in solution is more stable at acidic pH, in the absence of heavy metal ions, and protected from air.

Bronchodilator Agents↗
PubMed1987

Phenolic cyclization of epinephrine, metaproterenol, metaraminol, phenylephrine, and terbutaline with formaldehyde.

An exploratory study of the rates of cyclization of the title compounds, all 3-hydroxyphenalkanolamines, with formaldehyde to 1,2,3,4-tetrahydroisoquinolines (THIQs) was performed using high-performance liquid chromatographic (HPLC) methods. Reactions occur quantitatively and practically instantaneously at room temperature and neutral pH; thus, rates were measured at acid pH. Cyclization occurs ortho or para to the 3-phenolic function, so that all but the 3,5-dihydroxyphenyl derivatives, metaproterenol and terbutaline, gave two THIQs. Terbutaline reacted significantly slower than the other compounds. Formaldehyde occurs in pharmaceutical systems and it serves as a model for other aldehydes that occur in sugars and flavors. The pharmaceutical implications of the reaction are discussed.

Cyclization↗