The analytical solution for multi-compartment models with a non-zero initial condition is complex because of the inter-compartmental transfer. An elegant solution and its implementation in the ‘wnl' R package can be useful in solving examples of textbooks and developing software of therapeutic drug monitoring, pharmacokinetic simulation, and parameter estimation. This solution uses Laplace transformation, convolution, matrix inversion, and the fact that the general solution of an inhomogeneous ordinary differential equation is the sum of a homogenous and a particular solution, together.
Drug Monitoring

No abstract available.
Drug Monitoring ; Mycophenolic Acid

No abstract available.
Drug Monitoring ; Sirolimus ; Tacrolimus

No abstract available.
Cyclosporine ; Drug Monitoring

It is important to predict time to reach therapeutic concentration in phenytoin toxicity. In tradition, frequent drug monitoring is inevitable until the therapeutic serum level is reached. A method of estimating Vmax and Vd of phenytoin with application to estimating time to reach therapeutic concentration of phenytoin is described. We evaluated the usefulness of that method in twelve patients with phenytoin toxicity whose initial levels ranging from 27.7 to 74.0 ug/ml. We compaired the observed time defined as the time of returning from the initial toxic level to the optimum therapeutic level by serial measurement of serum concentration with the calculated time by using the modified Michaelis-Menten equation (Km x In (C1/C2) +Cl-C2=Vmax/vd x T). We determined individual patient's Vmax (maximal metabolic rate of concentration), Vd(volume of distribution of concentration), and Km(constants of Michaelis-Menten equation) for phenytoin, using data obtained from two consecutive serum concentration and known value of Km in Korean. And then, we calculated the decline time of phenytoin. The calculated decline time did not differ significantly from observed decline time (P=0.830). It is possible to predict the time to the therapeutic range and to reduce the unnecessarily frequent drug monitoring.
Drug Monitoring ; Humans ; Phenytoin*

BACKGROUND: We evaluated the Vitros 950 (Johnson & Johnson Clinical Diagnostics, Inc., NY, USA) in the measurement of digoxin and theophylline levels and compared its results to those of the TDxFLx II (Abbott Laboratories, IL, USA) used for therapeutic drug monitoring (TDM) world-widely in order to assess the utility of the Vitros 950 as a TDM instrument. METHODS: From June 1997 to August 1997, 125 and 135 candidates for TDM were randomly chosen to measure digoxin and theophylline, respectively, using the Vitros 950 and TDxFLx II. The relationship between its results and those of TDxFLx II were determined. The within-run and between-run precisions of the Vitros 950 were determined using two controls (Vitros Performance Verifier I and II; J & J Clinical Diagnostics, Inc., NY, USA). The high-concentration control (Vitros Performance Verifier II) was diluted in Vitros 7% BSA to 5 dilutions. And linearity for quantitative analysis of digoxin and theophylline were determined. RESULTS: The coefficients of variation (CV) for the within-run of the Vitro 950 were 0.8% - 4.4%. And the CV for between-run precision of the Vitro 950 were 1.7% - 12.3%. The linearity of digoxin and theophylline were relatively good. The correlations (r) of digoxin and theophylline levels with those determined by the Abbott TDxFLx II were 0.95 and 0.93, respectively (P <0.001). CONCLUSIONS: The recently developed dry slide method of the Vitros 950 proves to good precision and linearity for quantitative analysis of digoxin and theophylline. Its results correlate well with those of the TDxFLx II. The Vitros 950 does not require an elaborate preparatory protocol for the sample, and is easy to use and maintain.So it is considered a highly feasible instrument for stat test.
Digoxin* ; Drug Monitoring ; Theophylline*

Background: Monitoring antimalarial drug quality should be conducted regularly in locals to enhance the effect of treatment for malaria \r\n', u'Objective: to study and analyze antimalarial drug quality\r\n', u'Subjects and methods: The study was carried out in 2007 for 5 provinces supported by the Global Fund: Ha Giang, Dien Bien, Thanh Hoa, Quang Tri and Gia Lai. Material were malaria drugs: artesunat, chloroquin, quinine, mefloquin, fansidar\u2026etc\r\n', u'Results and conclusion: The strict supervision on the anti-malarial drug quality by the National Malaria Control Program was very good and no substandard antimalarial drugs were detected. Evaluation of antimalarial drug quality and control was made for finding out the counterfeit drugs through sentinel sites in both private and public sectors. A total of 268 samples were collected, of which 13 samples were found substandard drugs (8 samples collected in private and 5 samples in public sectors). No counterfeit drugs were found. \r\n', u'
Antimalarial drug ; quality ; monitoring

No abstract available.
Drug Monitoring* ; Teicoplanin*

In 1999, 49 vaccine samples had been collected from the field in routine immunization days. The potency of the samples had been verified in National Centre of Control of Medio-Biological Products, Ha Noi. The results showed that the potency of all the vaccine samples is at the acceptable limit, type 2 is the most stable and type 3 is the least stable one
Poliovirus Vaccine, Oral ; Drug Monitoring

Recently a newer generation of antiepileptic drugs has been developed and rational polytherapy has become popular in everyday clinical practice for epilepsy management. All of newer antiepileptic drugs (AED) have undergone extensive clinical studies, but the information on the relationship between concentrations and effects is scarce. The concentration can depend on the individual variation, but explain the efficacy and toxicity in individual patient management. We assess the potential value of measuring the level of newer AED, which is one of therapeutic drug monitoring (TDM). The value of TDM is discussed based on pharmacokinetic characteristics and drug interactions. Although routine TDM in general cannot be recommended, TDM of the newer AED may be of value in selected cases.
Anticonvulsants ; Drug Interactions ; Drug Monitoring ; Epilepsy ; Humans