ISSN:
1432-1041
Keywords:
L-dopa
;
elderly
;
pharmacokinetics
;
bioavailability
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Summary Previous studies have suggested that the absorption of L-dopa in the elderly Parkinsonian patient might be unusually efficient. In the present investigation, the systemic availability of L-dopa was examined in 5 elderly Parkinsonian patients (mean age=77 years) and 6 young, healthy volunteers (mean age=26 years) following a single oral 300 mg dose of L-dopa. Quantitation of plasma levels of intact L-dopa was effected by ion-exchange column chromatography and spectrofluorimetry. The L-dopa plasma concentration-time profiles obtained confirmed the considerable intersubject variability in the absorption of L-dopa previously reported in the literature. Maximum plasma concentrations of L-dopa generally occurred within 60 min of administration of the dose. The existence of more than one plasma peak of L-dopa concentration was displayed in 45% of the subjects studied. This characteristic was not confined exclusively to either subject group. There was a significantly larger (P〈0.02) area under the plasma L-dopa concentration-time curve (AUC o ∞ ) in the elderly Parkinsonian patients (mean=234.69 µg · min/ml; SD=84.70) compared to the young, healthy volunteers (mean=82.33 µg · min/ml; SD=31.00). A significant (P〈0.01) correlation existed between AUC o ∞ and age (r=0.7970; n=11) among the subjects studied. The apparent elimination phase plasma half-life of L-dopa in the elderly Parkinsonian patients (mean=66.0 min; SD=11.1) was not significantly different to that observed in the young, healthy volunteers (mean=74.0 min; SD=18.1). These results suggest that there may be an age-related alteration to the disposition of orally administered L-dopa in the elderly Parkinsonian patient.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00561903
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