Mixed pharmacokinetic population study and diffusion model to describe ciprofloxacin lung concentrations

Tissue Penetration of Antimicrobials in Intensive Care Unit Patients: A Systematic Review-Part II

In patients that are admitted to intensive care units (ICUs), the clinical outcome of severe infections depends on several factors, as well as the early administration of chemotherapies and comorbidities. Antimicrobials may be used in off-label regimens to maximize the probability of therapeutic concentrations within infected tissues and to prevent the selection of resistant clones. Interestingly, the literature clearly shows that the rate of tissue penetration is variable among antibacterial drugs, and the correlation between plasma and tissue concentrations may be inconstant. The present review harvests data about tissue penetration of antibacterial drugs in ICU patients, limiting the search to those drugs that mainly act as protein synthesis inhibitors and disrupting DNA structure and function. As expected, fluoroquinolones, macrolides, linezolid, and tigecycline have an excellent diffusion into epithelial lining fluid. That high penetration is fundamental for the therapy of ventilator and healthcare-associated pneumonia. Some drugs also display a high penetration rate within cerebrospinal fluid, while other agents diffuse into the skin and soft tissues. Further studies are needed to improve our knowledge about drug tissue penetration, especially in the presence of factors that may affect drug pharmacokinetics.

Ciprofloxacin population pharmacokinetics during long-term treatment of osteoarticular infections

BACKGROUND

Ciprofloxacin is an antibiotic used in osteoarticular infections owing to its very good bone penetration. Very few pharmacokinetic data are available in this population.

OBJECTIVES

To investigate oral ciprofloxacin population pharmacokinetics in adult patients treated for osteoarticular infections and propose guidance for more effective dosing.

METHODS

A retrospective population-pharmacokinetic analysis was performed on 92 consecutive hospitalized patients in the orthopaedic department. Ciprofloxacin plasma samples were obtained on one or two occasions during treatment. Plasma concentration was measured using ultra-performance liquid chromatography system coupled with tandem mass spectrometry. Data analysis was performed using a non-linear mixed-effect approach via Monolix 2019R2.

RESULTS

A total of 397 plasma samples were obtained with 11.5% and 41.6% of patients being below the therapeutic target for Gram-negative and staphylococcal infections, respectively. Ciprofloxacin pharmacokinetics were best described by a two-compartment model with a first-order absorption. Ciprofloxacin apparent plasma clearances and volumes of distribution were dependent on patients' fat-free mass according to the allometric rule. Elimination clearance was also positively related to renal function through the modification of diet in renal disease equation (MDRD) and rifampicin co-administration. When patients are co-treated with rifampicin, ciprofloxacin dosage should be increased by 50% to 60%.

CONCLUSIONS

This study showed that free-fat mass was a better size predictor than total body weight for ciprofloxacin clearance and volumes terms. Moreover, both MDRD and rifampicin status were significant predictors of individual ciprofloxacin clearance. Our study suggests that individual adjustment of ciprofloxacin dose in osteoarticular infections with less-susceptible bacteria might be indicated to reach required efficacy targets.

Dextrin/poly (HEMA): pH responsive porous hydrogel for controlled release of ciprofloxacin

Herein, we report an oral route administration for ciprofloxacin hydrochloride delivery using dextrin and poly (2-hydroxyethyl methylacrylate) based crosslinked hydrogel (c-Dxt/pHEMA). Various characteristics such as FTIR spectra, XRD analyses, UV-VIS-NIR spectra, FESEM and E-SEM analyses, rheological characteristics, gel kinetics, deswelling characteristics as well as biodegradation study of the hydrogel have been carried out. FTIR, XRD along with solid state UV-VIS-NIR analyses explain the good compatibility between the drug and the hydrogel matrix. The in vitro release study demonstrates that c-Dxt/pHEMA releases ciprofloxacin in a sustained way (33.75% of drug has been released in 18h) and is expected to be a promising matrix for ciprofloxacin carrier. The release kinetics and mechanism suggest that drug release follows first order kinetics and non-Fickian diffusion mechanism. Finally, the hydrogel shows excellent physical stability as carrier for ciprofloxacin up to 3 months.

Probing the interaction of human serum albumin with ciprofloxacin in the presence of silver nanoparticles of three sizes: multispectroscopic and ζ potential investigation

The binding of ciprofloxacin to human serum albumin (HSA) in the presence and absence of silver nanoparticles of three sizes was investigated for the first time. For this purpose fluorescence spectroscopy, circular dichroism, UV-vis spectroscopy, and ζ potential techniques were employed under physiological conditions. The titration results indicated that ciprofloxacin quenched the fluorescence intensity of HSA through a static mechanism, but in the presence of Ag nanoparticles of sizes I and II there were two different kinds of interaction behavior. Results of circular dichroism indicated that the secondary structure of HSA was modified with increasing ciprofloxacin concentration. A comparison between resonance light scattering of binary and ternary systems allowed us to estimate the effect of silver nanoparticles on the initial formation and aggregation of ciprofloxacin with HSA. The ζ-potential results suggested induced conformational changes on HSA, thus confirming the experimental and theoretical results.

Survey: calculation of the characteristics of oral diffusion-controlled release dosage forms related to the drug

Oral dosage forms with controlled release exhibit various advantages over their immediate release counterparts, but they must be built adequately by dispersing the drug through the well-defined polymer matrix. This study is concerned with diffusion-controlled dosage forms to resolve the problems that appear: in vitro tests generally used for determining the kinetics of drug release do not take into account the nature of the drug. On the contrary, the plasma drug profiles obtained through in vivo tests strongly depend on the nature of the drug, through their typical pharmacokinetic parameters. Moreover, the effect of the stirring rate is difficult to evaluate. Following the demand from the FDA concerned with the in vitro/in vivo correlation, a numerical model was built so as to evaluate the plasma drug profile obtained with any drug delivered from a diffusion-controlled release dosage form. The results are expressed by connecting the half-life times of the drugs obtained either with bolus injection or with the dosage forms, for various values of the parameters of interest: the diffusivity of the matrix polymer and the size of the dosage form. Thus, these diagrams make it possible to promptly determine the characteristics of the dosage forms able to give the desired plasma drug profile for any drug. Of course, for each drug being defined by its pharmacokinetic parameters, the polymer matrix should be selected as a function of its diffusivity. Finally, the evaluation of the plasma drug profile is of effective help to determine quantitatively the effect of the intervariability of the patients as well as the effect of the patient's noncompliance.

Adapting therapy with repeated short-infusions to inter individual variability between patients

Because of the wide inter individual variability between patients and their marked differences in drug response, one of the major issues that arises is adapting the therapy in question to the particular patient. In hospital, it is possible to vary the conditions of intravenous (i.v.) drug delivery by means of short infusions repeated at certain intervals. In this study, review of this process has been presented, and a therapeutic method described. It essentially consists of two stages. The first concerns the time of the first infusion, and the course of drug elimination: from two analyses of the drug concentrations in the blood made at two different times, the pharmacokinetic parameters of the patient are determined. Stage 2 consists of repeated short infusions and the therapy is adapted to the particular patient by varying the conditions involved. Thus, either the amount of the dose based on the rate of infusion or the time interval between the repeated infusions are varied. In order to reach a general solution, master curves are built by using dimensionless numbers as co-ordinates, such as time expressed in terms of the half-life t0.5 of the drug, and the drug concentration at the peaks defined as a fraction of the first unchanged peak concentration.

Population pharmacokinetics of ciprofloxacin in pediatric and adolescent patients with acute infections

The aim of the present study was to characterize the population pharmacokinetics of ciprofloxacin in patients with and without cystic fibrosis ranging in age from 1 day to 24 years and to propose a limited sampling strategy to estimate individual pharmacokinetic parameters. Patients were divided into four groups according to the treatment schedule. They received ciprofloxacin by intravenous infusion (30 min) or by the oral route. The number of samples collected from each patient ranged from 1 to 12. The population parameters were computed for an initial group of 37 patients. The data were analyzed by nonlinear mixed-effect modeling by use of a two-compartment structural model. The interindividual variability in clearance (CL) was partially explained by a dependence on age and the patient's clinical status. In addition, a significant relationship was found between weight and the initial volume of distribution. Eighteen additional patients were used for model validation and evaluation of limited sampling strategies. When ciprofloxacin was administered intravenously, sampling at a single point (12 h after the start of infusion) allowed the precise and accurate estimation of CL and the elimination half-life, as well as the ciprofloxacin concentration at the end of the infusion. It should be noted that to take into account the presence of a lag time after oral administration, a schedule based on two sampling times of 1 and 12 h is needed. The results of this study combine relationships between ciprofloxacin pharmacokinetic parameters and patient covariates that may be useful for dose adjustment and a convenient sampling procedure that can be used for further studies.