INTRAV and ORAL: BASIC interactive computer programs for estimating pharmacokinetic parameters.

Two interactive computer programs, INTRAV and ORAL, were written to permit pharmacokinetic modeling of experimental data and to obtain pertinent values based on derived estimates. Both programs utilize BASIC language and were developed on a microcomputer with graphics capability. Drug concentration in blood, plasma, or serum with time following either nonabsorptive (intravenous) or absorptive (oral or intramuscular) administration is input, and a semilogarithmic display of data appears on a cathode-ray tube (CRT). The user selects limits for various linear segments using a movable cursor. On command, coefficients and exponents for the differential equation which describes those limits is computed and a nonlinear curve is fitted through the data set. Results from statistical tests are available in output formats permitting the user to determine the goodness of the selected limits. Commonly used pharmacokinetic parameters are also computed and appear on the output. Numerous graphic output options are also available to permit comparisons between data sets and/or estimates derived from other computer programs. INTRAV and ORAL were compared with the widely used programs CSTRIP, ESTRIP, and NONLIN. Both INTRAV and ORAL gave estimates which were almost identical with CSTRIP and ESTRIP, whereas those obtained with NONLIN were very similar, although not identical.