Pharmacokinetic models for the saturable absorption of cefuroxime axetil and saturable elimination of cefuroxime. The nisomer and pisomer photoisomerization dynamics is included. Extent f nick holford university of auckland, new zealand. When you hear the term nonlinear pk in the future, you can just say to yourself aha, the drug exhibits saturable clearance at high doses. The wavelength region between 570 nm and 650 nm is considered where the nisomer and pisomer absorption dynamics changes from shortwavelength to longwavelength sosi excitation. Graphene saturable absorption and applications in fiber. The lag time shifts the time of dosing as if the drug was in fact administered at a later time.
In contrast with saturable absorption sa, when the absorptive properties of sa material fade with increasing the intensity due to depletion of the. Nonequilibrium electrons induced by ultrafast laser excitation in a correlated electron material can disturb the fermi energy as well as optical nonlinearity. Osa characterization of dynamic nonlinear absorption of. Pharmacokinetic models for the saturable absorption of cefuroxime axetil and saturable elimination of cefuroxime article in european journal of pharmaceutical sciences 2123. However, a higher dose increases the risk of adverse events. Plasma concentrationtime data n 372 from 71 patients under sorafenib were analysed using nonlinear mixedeffect modelling to. Saturable and reverse saturable absorption at longitudinal surface plasmon resonance spr in gold nanorods au nrs have been observed using zscan and transient absorption techniques with femtosecond laser pulses.
The population estimate of the absorption lagtime was used as fixed parameter in the final model. Observation of saturable and reverse saturable absorption. Large reverse saturable absorption under weak continuous. Therefore, absorption rate constant and possibly bioavailability decrease with doses leading to concentrations at the absorption site above the maximal absorption capacity. Here, nonequilibrium electrons translate a semiconductor tis2 material into a plasma to generate broad band nonlinear optical saturable absorption w. Saturable absorption article about saturable absorption. Dec 05, 2012 a covariate analysis identified hematocrit as influencing the oral clearance of sirolimus. The model on the left requires an additional parameter to describe a saturable increase in extent of absorption with dose. The posthoc function of nonmem enabled estimation of the individual pharmacokinetic parameters using a bayesian approach taking both individual observations and population effects into account.
The absorption of artemisinin from gut to hepatic compartment was assumed to be firstorder, with or without a lagtime. All the abstracts for the past page meetings can be accessed online through either the search function on the left or by going to the relevant page meeting. Research open access saturable human neopterin response to interferon. The software rp resonator can be used for simulating q switching or mode locking with various kinds of saturable absorbers. Saturable definition of saturable by the free dictionary. In general, saturable absorption does not occur in situations with passive uptake. Nonmem data files require that the amount of each dose is recorded in the amt data item only at the time the dose is administered. In physics, absorption of electromagnetic radiation is how matter typically electrons bound in atoms takes up a photons energy and so transforms electromagnetic energy into internal energy of the absorber for example, thermal energy. To crosscheck the relationship between the plasmon resonances of the metasurfaces and the saturable absorption, the effect of the nr length on the modulation depth of the saturable absorption is. Particularly, under strong laser radiation, graphene can modulate laser field in amplitude due to saturable absorption sa, and in phase due to large kerr nonlinearity. Twodimensional 2d nanomaterials, especially the transition metal sulfide semiconductors, have drawn great interests due to their potential applications in viable photonic and optoelectronic devices, such as saturable absorbers sas and optical switches, etc. Increasing the dose results in a larger %ft mic due to this delayed absorption, despite the nonproportional increase in c max. The visual predictive check indicated that the final pharmacokinetic model adequately predicted observed concentrations. On occasion, with very large doses, absorption can slow due to the large amount of drug present in a confined space.
Each abstract is formally and uniformly referenced as indicated when viewing the abstract. The model on the right is approximately linear if the effect on bioavailability is small. The oral bioavailability of c, calculated by numeric integration of an amount of ca drug absorbed was 22 and 17% for 2. Your current flash player does not support this content. By using a repetition rate of 1 hz, induced transparency saturable absorption is obtained, while the increase in the repetition rate to 10hz notably produces the signature of a multiphotonic absorption induced absorption process in the sample. These included firstorder absorption followed by zeroorder absorption, zeroorder absorption followed by firstorder absorption, and a combined. In conclusion, the amoxicillin absorption rate appears to be saturable, which results in a nonlinear increase in c max and a later t max for higher doses. Most materials show some saturable absorption, but often only at very high optical intensities close to the optical damage. Saturable absorption and reverse saturable absorption in. Osborne has been involved in a wide variety of saturable reactor design projects over the years.
Although the drug absorption delay is a complex phenomenon, the standard approach for describing absorption delays in the pharmacokinetic analysis is rather simple, by introducing a lag time parameter. A semiphysiological pharmacokinetic model for artemisinin. In this work, tungsten disulfide ws2 based sa for ultrafast photonic applications was demonstrated. For example, aminoglycosides may cause renal nephrotoxicity, thereby altering renal drug excretion. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Pharmacokinetic models for the saturable absorption of. Saturable reactor winding configurations osborne has been involved in a wide variety of saturable reactor design projects over the years. Oct 18, 2011 sorafenib is an oral tyrosine kinase inhibitor approved for the treatment of advanced renal cell carcinoma and hepatocellular carcinoma. Dynamics of saturable absorption in the semiconductor. Rp photonics encyclopedia saturable absorbers, passive.
Optical limiting materials have been investigated for many years to protect eyes and sensors from high power lasers. This chapter also describes the rg850 material, and provides an overview of the entire thesis. It has been shown that the kodak 9740 dye used as a saturable absorber with nd lasers can be described with the aid of a simple twolevel model with an effective life time of the upper state 2 x lo seconds. A shift from saturable absorption to reverse saturable absorption was observed at higher input pump intensities. The optical processes in c60 can be modeled through a fivelevel system. Implementation of a transit compartment model for describing.
The saturable absorption dynamics of dodci in a femtosecond dye laser is studied theoretically. The nonlinear elimination could be attributed to a saturable renal tubular reabsorption of the antibiotic and nonlinear intestinal absorption of ca mediated by carrier system. The optimization and selection of the appropriate compartmental pk model is. In materials showing reverse saturable absorption rsa, the optical absorbance increases as the power of the light incident on them increases. If you encounter saturable drug absorption, there is generally no harm because higher doses will not result in higher drug exposure. Overview of absorption models and modelling issues mats o. Rp photonics encyclopedia saturable absorbers, passive mode. At lower excitation irradiances, the wavelength dispersion of saturable absorption has been determined near. For slow absorption, the maximum absorption rate constant k a1 max, amount of paliperidone at the absorption site when half of the maximum absorption rate was achieved k amt1 50, and hill factor. Pharmacokinetic studies pk modeling compartmental pk. Weve prepared the illustrations below to share six established saturable reactor element core and. The energy states include three levels of the singlet state, coupled to two levels of an excited triplet state. Nonlinear pk is an interesting area of research that is easily understood once you break it down into the component parts. The optical nonlinear absorption of the aqueous solution of platinum nanospheres protected by poly nvinyl2pyrrolidone was investigated using open aperture zscan method with nanosecond pulse laser at the wavelength of 532 nm.
Saturable absorption of sorafenib in patients with solid. Ws2 as a saturable absorber for ultrafast photonic. A semiphysiological pharmacokinetic model for artemisinin in healthy subjects incorporating autoinduction of metabolism and saturable firstpass hepatic extraction. Continuous wave laser induced thirdorder nonlinear optical properties of conducting polymers 16,17 unlike veterinary patients, however, people possess a saturable gastrointestinal transport mechanism that may preclude against accidental overdose. A covariate analysis identified hematocrit as influencing the oral clearance of sirolimus. She retired from the nonmem project group in 2001, though she continues to assist parttime. Plasma concentrationtime data n 372 from 71 patients under sorafenib were analysed using nonlinear mixedeffect modelling to estimate population pharmacokinetic. The saturable pattern of the neopterin response blurring the doseresponse relationship of srifn. Nonlinear absorption pharmacokinetics of amoxicillin. Abstract the optical nonlinear absorption of the aqueous solution of platinum nanospheres protected by poly nvinyl2pyrrolidone was investigated using open aperture zscan method with nanosecond pulse laser at the wavelength of 532 nm. You can also be certain that at high doses, exposure increases faster than dose.
The pharmacokinetics of sirolimus, based on whole blood concentrations, appears to be nonlinear due to saturable absorption. The nonlinear mixedeffects method is depicted in figure 10. Saturable definition of saturable by medical dictionary. Roxithromycin displays saturable absorption and protein binding leading to lower exposure and lower target attainment at mics. The absorption lagtime for artemisinin was estimated using logtransformed concentration data from the standarddose group group a on day 1, described by a onecompartment model with oral absorption. This indicates the reverse saturable absorption rsa type of process. Five absorption rate models have been compared for describing cefetamet data in 34 adults after oral administration of cefetamet pivoxil with food alone or in combination with either an antacid or an h2 antagonist. A shift from saturable absorption to reverse saturable absorption was observed at higher input pump.
This poster describes a simulation of reverse saturable absorption in a solution c60 molecules using the comsol multiphysics software. By using a population approach, this study aimed to characterise its pharmacokinetics. Research open access saturable human neopterin response to. Graphene saturable absorption and applications in fiber laser. A class of nonlinear absorbers in which the excited state absorption is large compared to the ground state absorption can undergo a process called reverse saturable absorption rsa, also known as reversible saturable absorption. A sequential zero then firstorder input process provided the most flexible description of the absorption rate of cefetamet. She also helped stuart and lewis with many implementation issues of nonmem. A saturable absorber is an optical component with a. Dynamic nonlinear absorption of compositetype singlewall carbon nanotube saturable absorbers is characterized using both femtosecond and picosecond pump pulses. Saturable absorption article about saturable absorption by. We acknowledge the many contributions to this document from the participants of previous workshops. Saturable reactors are used in systems when a drop in full line voltage with complete linearity, a need to limit voltage spikes, sags and harmonics is required.
Saturable absorption is a nonperturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Besides saturation of plasma proteinbinding or carriermediated systems, drugs may demonstrate nonlinear pharmacokinetics due to a pathologic alteration in drug absorption, distribution, and elimination. In contrast with saturable absorption sa, when the absorptive properties of sa material fade with increasing the. Pdf saturable human neopterin response to interferon. A notable effect attenuation is to gradually reduce the intensity of light waves as they propagate through a medium. Nonlinear population pharmacokinetics of sirolimus in. It is based on the principle that the individual pharmacokinetic parameters of a patient population arise from a distribution that can be described by the population mean and the interindividual variance. Ultrafast saturable absorption in tis2 induced by non. To soak or fill so that no more liquid may be absorbed. These materials must be able to absorb or scatter high intensity laser radiation, while transmitting low. Nov 21, 2014 twodimensional 2d nanomaterials, especially the transition metal sulfide semiconductors, have drawn great interests due to their potential applications in viable photonic and optoelectronic devices, such as saturable absorbers sas and optical switches, etc. Saturable absorption is a property of materials where the absorption of light decreases with increasing light intensity.
In this study, we developed a pharmacokinetic pk pharmacodynamic pd model of a new sustained release formulation of interferon. A semiphysiological pharmacokinetic model for artemisinin in. Sorafenib is an oral tyrosine kinase inhibitor approved for the treatment of advanced renal cell carcinoma and hepatocellular carcinoma. Results are compared with numerical simulations based on two commonly used saturable absorber models. Power magnetics supplies the most reliable saturable reactors available, using our design and manufacturing expertise to meet the demands of industry.
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