| Abstrakt: |
A new method employing the principle of superimposition was developed to aid in the formulation of sustained-release dosage forms. Independently absorbed components of a product, e.g., waxed pellets for an oral capsule, are administered separately and their plasma level-time profiles determined. Using a trial and error procedure, the ratios of pellets are varied to obtain a desired plasma level-time profile. The use of ( 1) time averaged plasma concentration-time data, ( 2) amount remaining to be absorbed (excreted) plots, and ( 3) cumulative amount absorbed (excreted) plots were all shown to be inappropriate for pharmacokinetic analyses in general, and evaluation of sustained-release products in particular. It was recommended that raw plasma concentration-time data be made available for sustained-released products, and that individual rate of absorption plots be used to assess absorption kinetics. It was concluded that much of the sustained-release pharmacokinetic data presently in the literature have been presented in such a manner, e.g. averaged data, as to be of limited value. [ABSTRACT FROM AUTHOR] |
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