1
|
Danhof M. Kinetics of drug action in disease states: towards physiology-based pharmacodynamic (PBPD) models. J Pharmacokinet Pharmacodyn 2015; 42:447-62. [PMID: 26319673 PMCID: PMC4582079 DOI: 10.1007/s10928-015-9437-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 08/17/2015] [Indexed: 11/26/2022]
Abstract
Gerhard Levy started his investigations on the "Kinetics of Drug Action in Disease States" in the fall of 1980. The objective of his research was to study inter-individual variation in pharmacodynamics. To this end, theoretical concepts and experimental approaches were introduced, which enabled assessment of the changes in pharmacodynamics per se, while excluding or accounting for the cofounding effects of concomitant changes in pharmacokinetics. These concepts were applied in several studies. The results, which were published in 45 papers in the years 1984-1994, showed considerable variation in pharmacodynamics. These initial studies on kinetics of drug action in disease states triggered further experimental research on the relations between pharmacokinetics and pharmacodynamics. Together with the concepts in Levy's earlier publications "Kinetics of Pharmacologic Effects" (Clin Pharmacol Ther 7(3): 362-372, 1966) and "Kinetics of pharmacologic effects in man: the anticoagulant action of warfarin" (Clin Pharmacol Ther 10(1): 22-35, 1969), they form a significant impulse to the development of physiology-based pharmacodynamic (PBPD) modeling as novel discipline in the pharmaceutical sciences. This paper reviews Levy's research on the "Kinetics of Drug Action in Disease States". Next it addresses the significance of his research for the evolution of PBPD modeling as a scientific discipline. PBPD models contain specific expressions to characterize in a strictly quantitative manner processes on the causal path between exposure (in terms of concentration at the target site) and the drug effect (in terms of the change in biological function). Pertinent processes on the causal path are: (1) target site distribution, (2) target binding and activation and (3) transduction and homeostatic feedback.
Collapse
Affiliation(s)
- Meindert Danhof
- Leiden Academic Centre for Drug Research, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands.
| |
Collapse
|
2
|
Höcht C, Opezzo JAW, Bramuglia GF, Taira CA. Application of microdialysis for pharmacokinetic-pharmacodynamic modelling. Expert Opin Drug Discov 2006; 1:289-301. [DOI: 10.1517/17460441.1.4.289] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
3
|
Pérez-Urizar J, Granados-Soto V, Flores-Murrieta FJ, Castañeda-Hernández G. Pharmacokinetic-pharmacodynamic modeling: why? Arch Med Res 2000; 31:539-45. [PMID: 11257318 DOI: 10.1016/s0188-4409(00)00242-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
At present, pharmacokinetic-pharmacodynamic (PK-PD) modeling has emerged as a major tool in clinical pharmacology to optimize drug use by designing rational dosage forms and dosage regimes. Quantitative representation of the dose-concentration-response relationship should provide information for prediction of the level of response to a certain level of drug dose. Several mathematical approaches can be used to describe such relationships, depending on the single dose or the steady-state measurements carried out. With concentration and response data on-phase, basic models such as fixed-effect, linear, log-linear, E(MAX), and sigmoid E(MAX) can be sufficient. However, time-variant pharmacodynamic models (effect compartment, acute tolerance, sensitization, and indirect responses) can be required when kinetics and response are out-of-phase. To date, methodologies available for PK-PD analysis barely suppose the use of powerful computing resources. Some of these algorithms are able to generate individual estimates of parameters based on population analysis and Bayesian forecasting. Notwithstanding, attention must be paid to avoid overinterpreted data from mathematical models, so that reliability and clinical significance of estimated parameters will be valuable when underlying physiologic processes (disease, age, gender, etc.) are considered.
Collapse
Affiliation(s)
- J Pérez-Urizar
- Departamento de Farmacología y Toxicología, Centro de Investigación y de Estudios Avanzados del I.P.N. (CINVESTAV), Apdo. Postal 22026, 14000 Mexico City, Mexico.
| | | | | | | |
Collapse
|
4
|
Abstract
Deterred by the complexity of the mathematics, pharmacologists and clinical pharmacologists have only recently appreciated the usefulness of pharmacokinetics in drug development. Now unfortunately, although the vernacular of the science is known, often the meaning behind the words is lost. It is often assumed that drug levels are linearly related to drug action. Frequently they are not. This review shows, with reference to psychotropic drugs, how, in simple terms, it is possible to relate pharmacokinetics with pharmacodynamics, and how such relationships may provide a greater insight into drug activity and enhance drug development. Assuming that an equilibrium exists between the drug in plasma levels, and at the site of action, the same Michaelis-Menten equations used to relate effect to drug receptor binding can be used for drug level-dynamic interactions. A number of these relationships have been published and are discussed in terms of their derivation and their limitations. The graphical and computerised methods to create complete Emax curves are described and how the parameters of maximal effect, potency, variability and slope can be measured. When the drug is not in equilibrium with its site of action, hysteresis occurs and drug levels are out of phase with activity. Anticlockwise hysteresis, that is, activity increasing with time for a given drug level, can be caused by uptake into an active site, active metabolites, cascade activity, and sensitisation whilst clockwise hysteresis, in which activity decreases with time, can be caused by tolerance, active antagonistic metabolites, learning effects and feedback regulation. Attempts to relate simultaneously kinetics and dynamics by Link models can be difficult and not always necessary. It is assumed in therapeutic drug monitoring that individuals will show the same response for a given drug level. On the contrary, differences in individual subject sensitivity to drugs measured by kinetic-dynamic relationships may provide a greater understanding of the disease itself.
Collapse
Affiliation(s)
- D B Campbell
- Servier Research and Development Limited, Fulmer, Slough, UK
| |
Collapse
|
5
|
Abstract
The relationship between phenytoin-induced ataxia and its concentration was characterized in rats who received i.v. infusions of the drug at either 0.52, 0.85 or 1.70 mg/min/rat until the onset of ataxia. Phenytoin dose to ataxia did not change with infusion rate but the total and unbound serum concentrations at onset of ataxia increased with increasing infusion (input) rate. Concentrations in cerebrospinal fluid, CSF, and in brain, at this end-point, were not affected by the infusion rate. Direct i.v. infusion of phenytoin major metabolite, p-HPPH, failed to produce ataxia. Thus phenytoin in CSF and brain, unlike serum phenytoin, equilibrates rapidly with site(s) of phenytoin neurotoxicity and represents appropriate sampling sites for identifying factors affecting phenytoin neurotoxicity.
Collapse
Affiliation(s)
- I Ramzan
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, PA
| |
Collapse
|
6
|
Shek E, Murakami T, Nath C, Pop E, Bodor NS. Improved anticonvulsant activity of phenytoin by a redox brain delivery system. III: Brain uptake and pharmacological effects. J Pharm Sci 1989; 78:837-43. [PMID: 2600790 DOI: 10.1002/jps.2600781012] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Phenytoin (DPH) was delivered to the brain by a dihydropyridine in equilibrium pyridinium salt redox system, which was evaluated for anticonvulsant activity. Following iv injection of the lipophilic delivery system of DPH (2) to rats, concentrations of DPH were lower but sustained and, after 30 min, essentially the same as the levels after equimolar administration of DPH. While 2 delivered the same levels of DPH to the brain as DPH did, it was twice as potent as DPH in rats (ED50 was 7.5 mumol/kg for 2 and 14.2 mumol/kg for DPH) and mice (2: 10.5; DPH: 23.9) against maximal electroshock seizures (MES), and seven times more potent in mice (2: 10.0, DPH: 70.6) against maximal pentylenetetrazole seizures (MPS). Moreover, 2 was active against pentylenetetrazole threshold seizures (PTS) in mice and rats (ED50 = 44.1 and 40.5 mumol/kg, respectively), while DPH was ineffective (up to a dose of 79.2 mumol/kg). After evaluation of acute neurological toxicity in rats, 2 was found to possess 1.5 times higher a protective index (for MES) than DPH. It appeared also that while DPH was 2.9 times less sensitive to MPS than to MES, 2 was equally potent to both types of convulsions. Thus, the data indicate that 2 delivered DPH more efficiently to the brain. The better anticonvulsant activity (quantitatively as well as qualitatively) of 2 can be explained on the basis of an improved distribution in the brain due to its higher lipophilicity, and by favorable regional differences in the rates of conversion of 2 to DPH at the convulsing foci.
Collapse
Affiliation(s)
- E Shek
- University of Florida, Center for Drug Design and Delivery, Gainesville
| | | | | | | | | |
Collapse
|
7
|
Ramzan I, Levy G. Relationship between concentration and anticonvulsant effect of phenytoin against electroshock-induced seizures in rats: comparison of sampling sites for concentration determinations. J Pharm Sci 1989; 78:448-51. [PMID: 2760817 DOI: 10.1002/jps.2600780604] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The purpose of this investigation was to determine the optimum sampling site for phenytoin concentration measurements in the context of pharmacodynamic studies of the anticonvulsant effect of phenytoin. Determination of drug concentrations in the serum, serum water, brain, and cerebrospinal fluid (CSF) of rats as a function of time after iv injection of a 6-mg/kg dose revealed a significant disequilibrium between brain and serum water for 15 min and between CSF and serum water for 5 min after injection. The concentrations of phenytoin in serum water 1 min after injection of 3 mg/kg (0.371 +/- 0.054 microgram/mL) and 45 min after injection of 8 mg/kg (0.399 +/- 0.049 microgram/mL) were not significantly different, but drug concentrations in the CSF and brain were appreciably higher after the latter dose. There was no protection against electroshock-induced seizures 1 min after the 3-mg/kg dose, but there was complete protection 45 min after the 8-mg/kg dose. At 15 min after drug injection, phenytoin concentrations in CSF and serum water were essentially identical over a wide concentration range. Fifty female Lewis rats weighing approximately 225 g, that consistently exhibited maximal electroshock-induced seizures in three preliminary trials on separate days, received 1, 2, 4, 6, or 8 mg/kg of phenytoin by iv injection. Electroshock was applied 15 min later, the percentage of animals protected from seizure by each dose was determined, and drug concentrations in serum, serum water, brain, and CSF were measured by gas chromatography. The relationship between anticonvulsant activity and drug concentration could be described by a Hill-type equation.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- I Ramzan
- Department of Pharmaceutics, School of Pharmacy, State University of New York, Buffalo, Amherst 14260
| | | |
Collapse
|
8
|
Dingemanse J, Thomassen D, Mentink BH, Danhof M. Strategy to assess the role of (inter)active metabolites in pharmacodynamic studies in-vivo: a model study with heptabarbital. J Pharm Pharmacol 1988; 40:552-7. [PMID: 2907009 DOI: 10.1111/j.2042-7158.1988.tb05301.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The purpose of this investigation was to develop a universal experimental strategy by which the role of (inter)active metabolites in in-vivo pharmacodynamic studies can be examined. Heptabarbital was chosen as a model drug and several pharmacokinetic variables which may affect in-vivo concentration-pharmacological response relationships were examined. Adult female rats received an i.v. infusion of the drug at one of three different rates (0.225-1.50 mg min-1) until the animals lost their righting reflex (after 11 +/- 1 to 88 +/- 8 min of infusion). The serum concentration of the drug at onset of loss of righting reflex (LRR) increased slightly with increasing infusion rate. The drug concentrations in brain tissue and cerebrospinal fluid (CSF), (mean +/- s.d.: 67 +/- 5 mg kg-1 and 24 +/- 4 mg L-1, respectively, for the lowest infusion rate) were not affected by the infusion rate. The possible contribution of (inter)active metabolites to the pharmacological response of heptabarbital was determined by administration of different i.v. bolus doses (14.1-22.5 mg) resulting in widely differing sleeping-times (7 +/- 3 to 119 +/- 20 min). The concentrations of heptabarbital in serum, brain tissue and CSF at offset of LRR (mean +/- s.d.: 77 +/- 8 mg L-1, 76 +/- 7 mg kg-1 and 29 +/- 5 mg L-1, respectively, for the highest dose) were not affected by the administered dose.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J Dingemanse
- Division of Pharmacology, University of Leiden, Sylvius Laboratories, The Netherlands
| | | | | | | |
Collapse
|
9
|
Dingemanse J, Danhof M, Breimer DD. Pharmacokinetic-pharmacodynamic modeling of CNS drug effects: an overview. Pharmacol Ther 1988; 38:1-52. [PMID: 3293088 DOI: 10.1016/0163-7258(88)90101-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- J Dingemanse
- Center for Bio-Pharmaceutical Sciences, State University of Leiden, Sylvius Laboratories, The Netherlands
| | | | | |
Collapse
|
10
|
Ramzan IM, Levy G. Kinetics of drug action in disease states. XV: Effect of pregnancy on the convulsive activity of pentylenetetrazol in rats. J Pharm Sci 1985; 74:1233-5. [PMID: 3878872 DOI: 10.1002/jps.2600741119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The purpose of this investigation was to determine whether the pharmacodynamics of the central nervous system stimulant pentylenetetrazol (1) are altered in advanced pregnancy. Lewis rats that were 20 days pregnant and nonpregnant rats of the same age and strain received either a relatively fast or a relatively slow intravenous infusion of 1 until the onset of a maximal seizure, which occurred after about 11 or 31 min, respectively, of infusion. The concentrations of 1 at that time in serum, cerebrospinal fluid, (CSF) and brain were independent of the infusion rate and did not differ significantly between pregnant and nonpregnant animals. The ratio of concentrations of 1 in the cerebrospinal fluid to that in serum was unity in all groups, consistent with negligible serum protein binding and indicative of rapid penetration of 1 into the central nervous system. It is concluded that advanced pregnancy has no apparent effect on the response of the central nervous system of rats to the convulsive activity of 1.
Collapse
|