FireBoard Site Syndication http://software.monolix.org/sdoms/software Thu, 09 Sep 2010 08:05:07 +0200 FireBoard 1.0.5RC2 http://software.monolix.org/sdoms/software/components/com_fireboard/template/default_ex/images/english/emoticons/rss.gif http://software.monolix.org/sdoms/software FireBoard Site Syndication http://software.monolix.org/sdoms/software/index.php?/Forum/Category-32/791-log-normal-distribution-of-parameters.html#793 Hi Obelix, The following article may be of help. Title: Common noncompartmental pharmacokinetic variables: are they normally or log-normally distributed? Authors: L. F. Laceya; O. N. Keeneb; J. F. Pritchardc; A. Byea Published in: Journal of Biopharmaceutical Statistics, Volume 7, Issue 1 1997 , pages 171 – 178 Abstract We investigated the hypothesis that distributions of continuous pharmacokinetic variables are positively skewed in nature and that logarithmic transformation of these variables restores normality. The distributions of common continuous noncompartmental pharmacokinetic variables were investigated for four different Glaxo Wellcome compounds, administered by three different routes of administration: ranitidine (po), sumatriptan (sc), ondansetron (iv), and bismuth, from ranitidine bismuth citrate (po). The distributions of all the investigated noncompartmental pharmacokinetic variables were adequately described by a log-normal distribution, whereas statistically significant departures from normality occurred in the majority of cases. Thus, unless there is strong and consistent evidence for a departure from log-normality, the parametric statistical analysis of common noncompartmental pharmacokinetic variables should be carried out a priori log transformation. Link: http://www.informaworld.com/smpp/content~db=all~content=a776178751~frm=titlelink All the best, Barry Mon, 06 Sep 2010 22:13:50 +0200 http://software.monolix.org/sdoms/software/index.php?/Forum/Category-26/384-modeling-data-on-the-natural-log-scale.html#792 I was wondering where I can find examples of writing residual error model for log transformed data e.g. log(Y) = log(F)+W*EPS(1) Thanks.. Santosh Sun, 05 Sep 2010 08:17:01 +0200 http://software.monolix.org/sdoms/software/index.php?/Forum/Category-40/785-Covariate-picture-weight-depending-on-time.html#790 Thank you Hector I guess I understood your answer. Maybe I came back with some further question in the next days. Sun, 05 Sep 2010 00:20:52 +0200 http://software.monolix.org/sdoms/software/index.php?/Forum/Category-30/632-Installation-on-OS-X-and-Matlab2009b.html#789 Sorry, file now attached. http://software.monolix.org/sdoms/software/images/fbfiles/files/log.txt Thu, 02 Sep 2010 17:18:06 +0200 http://software.monolix.org/sdoms/software/index.php?/Forum/Category-26/694-Sequential-Independent-Zero-and-First-Order-Model.html#786 Hello Monolix users, I would like to implement a parallel first order absorption model (similar to this problem that Julie worked on a while ago). However, I have multiple dose data (as well as single dose), SC and IV. Can someone let me know if this is doable in Monolix? If you have an example for me to follow, I'd greatly appreciate it. Thank you in advance, -Thuy Wed, 01 Sep 2010 01:25:05 +0200 http://software.monolix.org/sdoms/software/index.php?/Forum/Category-38/781-Creating-a-data-file.html#784 Hi Hector I solved my problem. I separated the columns by the tab-button only and everything works fine now. Thanks for your support! Sun, 29 Aug 2010 20:18:21 +0200 http://software.monolix.org/sdoms/software/index.php?/Forum/Category-26/778-first-order-oral-administration.html#780 Dear Hector, Thank you very much for the reply. I removed the term D*KADMI*exp(-KADMI*max(T-t_dose,0)), but the descrepancy with Matlab code persists. I found that introducing the term D*ka*exp(-ka*max(T-t_dose,0)) without $PK section does not numerical problems; this way coinsides with Matlab simulations vey good. The problem is rather with $PK section and KA1=ka term without D*ka*exp(-ka*max(T-t_dose,0)). This way leads to the discrepancies with Matlab and I do not understand why. The following model coinsides with independent simulations: $PROBLEM First order absorption with one compartment and induction; parameters: ka, V1, Q, V2, Cl $MODEL $PSI ka Cl V1 max_ind induc deg $DOSE t_dose D $ODE A_0(2)=0 STIFF DADT(1) = -(Cl*max(0,(1+A(2)))/V1)*A(1)+D*ka*exp(-ka*max(T-t_dose,0)) DADT(2) = induc*max(0,max_ind-abs(A(2)))*A(1)/V1-deg*A(2) $OUTPUT OUTPUT1 = A(1)/V1 The alternative model slightly differs from Matlab simulation: $PROBLEM First order absorption with one compartment and induction; parameters: ka, V1, Q, V2, Cl $MODEL $PSI ka Cl V1 max_ind induc deg $PK KA1 = ka $ODE A_0(2)=0 STIFF DADT(1) = -(Cl*max(0,(1+A(2)))/V1)*A(1) DADT(2) = induc*max(0,max_ind-abs(A(2)))*A(1)/V1-deg*A(2) $OUTPUT OUTPUT1 = A(1)/V1 Yuri Tue, 24 Aug 2010 13:28:25 +0200 http://software.monolix.org/sdoms/software/index.php?/Forum/Category-40/776-Importing-NONMEM-models.html#777 Hi, In monolix, you only write in MLXTRAN the model, not the whole project as in NONMEM.In this case, the sections $DATA, $INPUT, $THETA, etc are chosen in the interface. You can find some examples on how to write you own model and how to define your parameters ($PSI section), regression variables ($REG) and on how monolix handle doses. You must know that in monolix, we make a difference between covariates (used in the covariate model to define the way the individual parameters are computed),which can not change on time except for IOV studies where it can be different between (but not within) occasions; and the regression variables that are passed directly to the model. In this case, I think that you should set WT and HT as "X" so you can compute BSA and LBM inside the model. For AGE, you can use it as covariate by transforming it as AGE-53. Also, you will need to include the differential equations ($ODE section for monolix) Best regards, Hector Mesa Tue, 24 Aug 2010 10:07:43 +0200 http://software.monolix.org/sdoms/software/index.php?/Forum/Category-32/775-Unalble-to-load-project-from-evaulation-folder.html#775 Hi, I’ve been trying to rerun the evaluation of Monolix on my computer and compare it to the results that that you have so kindly documented (RESULTS_EVAL_PK.pdf). I have no problem when loading the data files such as bolus_1cpt_VCL_SD_data.txt and running the appropriate model but I am unable to load a project such as bolus_1cpt_VCL_SD_projct.mat. I am able to load projects from the demo folder and my own folder the problem only occurs with the projects from the evaluation folder. I am running Monolix 3.1R for Windows StandAlone version. Thanks very much, Barry Wed, 11 Aug 2010 18:33:00 +0200