Pharmacokinetics of intermittent dosed intravenous vancomycin in adult persons with cystic fibrosis

Novel Dry Hyaluronic Acid-Vancomycin Complex Powder for Inhalation, Useful in Pulmonary Infections Associated with Cystic Fibrosis

Polyelectrolyte-drug complexes are interesting alternatives to improve unfavorable drug properties. Vancomycin (VAN) is an antimicrobial used in the treatment of methicillin-resistant Staphylococcus aureus pulmonary infections in patients with cystic fibrosis. It is generally administered intravenously with a high incidence of adverse side effects, which could be reduced by intrapulmonary administration. Currently, there are no commercially available inhalable formulations containing VAN. Thus, the present work focuses on the preparation and characterization of an ionic complex between hyaluronic acid (HA) and VAN with potential use in inhalable formulations. A particulate-solid HA-VAN25 complex was obtained by spray drying from an aqueous dispersion. FTIR spectroscopy and thermal analysis confirmed the ionic interaction between HA and VAN, while an amorphous diffraction pattern was observed by X-ray. The powder density, geometric size and morphology showed the suitable aerosolization and aerodynamic performance of the powder, indicating its capability of reaching the deep lung. An in vitro extended-release profile of VAN from the complex was obtained, exceeding 24 h. Microbiological assays against methicillin-resistant and -sensitive reference strains of Staphylococcus aureus showed that VAN preserves its antibacterial efficacy. In conclusion, HA-VAN25 exhibited interesting properties for the development of inhalable formulations with potential efficacy and safety advantages over conventional treatment.

Population pharmacokinetics and target attainment analysis of vancomycin after intermittent dosing in adults with cystic fibrosis

Vancomycin is the first-line agent to treat pulmonary infections caused by methicillin-resistant Staphylococcus aureus (MRSA) in people with cystic fibrosis (PwCF). However, there is no consensus on vancomycin initial dosing in this population among health institutions, and there is a large variability in initial dosing across the United States. In this study, we characterized the pharmacokinetics (PK) of vancomycin in PwCF using a population PK approach. The clinical PK data to develop the population PK model were obtained from vancomycin therapeutic monitoring data from PwCF undergoing treatment for infections due to MRSA. The population PK model was then used to perform comprehensive Monte Carlo simulations to evaluate the probability of target attainment (PTA) of 12 different initial dosing scenarios. The area under the curve to minimum inhibitory concentration (MIC) ratio ≥400 mg*h/L and <650 mg*h/L were used as efficacy and toxicity targets for PTA analysis. A total of 181 vancomycin plasma concentrations were included in the analysis. A one-compartment model with first-order elimination best described the data. Weight significantly influenced the vancomycin PK (P < 0.05). In the final model, clearance was estimated as 5.52 L/h/70 kg, and the volume of distribution was 31.5 L/70 kg. The PTA analysis showed that at MIC = 1 µg/mL, doses 1,500 q8h and 2,000 q12h showed the highest %PTA in achieving both efficacy and toxicity targets. The PTA results from this study may potentially inform the initial dosing regimens of vancomycin to treat pulmonary infections due to MRSA in PwCF.

The pharmacokinetics and pharmacodynamics of continuous infusion vancomycin in adult people with cystic fibrosis

BACKGROUND

The American Thoracic Society Guidelines recommend vancomycin as first line option for treatment of methicillin-resistant Staphylococcus aureus. Two studies have described the pharmacokinetics (PK) of intermittent intravenous (IV) vancomycin in adult people with cystic fibrosis (PwCF). Currently, there have not been any studies describing the PK of continuous infusion vancomycin in PwCF. Our study aimed to describe the PK of continuous infusion vancomycin in adult PwCF.

METHODS

Included patients were adult PwCF, who were admitted to University of Utah Hospital between May 11, 2014 and August 31, 2020, and received continuous infusion vancomycin for the treatment of an pulmonary exacerbations. The primary outcome was to describe vancomycin clearance rate (CLvanco ) and total daily dose (TDD). Secondary outcomes included rates of acute kidney injury (AKI), liver injury, and infusion-related reactions.

RESULTS

Twenty patients were included in this study. The mean CLvanco was 5.08 L/h on Day 3 and 4.58 L/h on Day 7 (p = .04), and the TDD increased from 2444 mg on Day 3 to 2556 on Day 7, although not statistically significant (p = 0.26). Zero patients experienced an AKI, two patients experienced liver injury, and no patients experienced infusion-related reactions.

CONCLUSIONS

This study demonstrates that continuous infusion vancomycin PK, namely CLvanco , is similar to previously reported CLvanco for intermittent dosed IV vancomycin in adult PwCF. This study suggests that continuous infusion vancomycin is likely safe to use in adult PwCF.