Subcutaneously administered antibiotics: a review

Safety, tolerability and pharmacokinetics of subcutaneous meropenem as an alternative to intravenous administration

BACKGROUND

Subcutaneous delivery of antibiotics is a practical alternative to IV administration. Meropenem is commonly used to treat infections caused by resistant Gram-negative organisms.

METHODS

This was a prospective, crossover self-controlled study in 11 stable inpatients established on meropenem. Participants received a single dose of subcutaneous meropenem, in 50 mL normal saline via gravity feed. Venous blood sampling was performed at baseline, 0.5, 1, 2, 4 and 8 h following the subcutaneous and IV doses. Antibiotic concentrations were measured using UPLC-MS/MS. Pharmacokinetic data were analysed using a non-linear mixed-effects modelling approach. Pain scores and infusion site reactions (oedema/erythema) were assessed.

RESULTS

Subcutaneous meropenem was well tolerated. The bioavailability of subcutaneous administration was 81.5% (95% CI 71.6%-93.2%). Increasing BMI was associated with slower absorption from subcutaneous tissue. Compared with IV, subcutaneous administration resulted in lower peak and higher trough concentrations. Despite the lower bioavailability observed, the PTA for free drug concentrations greater than the MIC for more than 40% of the time between doses was higher for subcutaneous than IV administration at MIC values between 0.03 and 8 mg/L. Simulated subcutaneous doses of 1.5 g twice daily, or 3 g continuous 24 h infusion had improved PTA relative to standard IV dosing of 1 g three times daily.

CONCLUSIONS

Subcutaneous meropenem appears to be well tolerated and has a favourable pharmacokinetic profile. Either 1.5 g twice daily or 3 g as a 24 h subcutaneous infusion could be considered for future evaluation.

Safety, tolerability and pharmacokinetics of subcutaneous cefazolin as an alternative to intravenous administration

BACKGROUND

Subcutaneous (SC) administration of antibiotics is a practical alternative to IV administration. Cefazolin is widely used for skin and soft tissue infections and other complex infections by IV administration.

METHODS

In this prospective, cross-over self-controlled study, a single dose of SC cefazolin was administered to 15 stable inpatients established on IV cefazolin as part of their management plan. The equivalent dose of cefazolin was diluted in 50 mL of normal saline via gravity feed over 30 min. Venous blood samples were collected at baseline and 0.5, 1, 2, 4 and 8 h following both the SC and IV doses. Antibiotic concentrations were measured using UPLC-MS/MS. Pharmacokinetic data were analysed using a non-linear mixed-effects modelling approach. Pain scores and infusion site reactions (oedema/erythema) were evaluated.

RESULTS

SC cefazolin was well tolerated. The bioavailability of SC administration was 74.8% (95% CI 66.7%-81.7%). Slower absorption from SC tissue was associated with a BMI of ≥30. Lower peak, and higher trough concentrations were observed with SC administration. Although lower bioavailability was observed with SC administration, the PTA for unbound drug concentrations greater than the MIC for more than 90% of the time between doses was higher for SC compared with IV administration at MICs between 0.25 and 4 mg/L. Simulated SC doses of 3 g twice daily had similar PTA to standard IV dosing of 2 g three times daily. A simulated 6 g continuous 24 h infusion of SC cefazolin had a favourable pharmacokinetic profile.

CONCLUSION

SC cefazolin appears to be well tolerated, with an improved pharmacokinetic profile compared with IV administration. Either 3 g twice daily, or 6 g as a 24 h SC infusion could be considered for future evaluation.

Comparative pharmacokinetic evaluation of metronidazole in sheep and goats

Metronidazole (MTZ) is a 5-nitroimidazole compound recognized for its dual anti-bacterial and anti-protozoal properties. Non-approved in many countries for farm medicine, due to a lack of data in the literature, the study aimed to determine its pharmacokinetics (PK) in sheep and goats following intravenous (IV) and subcutaneous (SC) administrations. Sheep (n = 5) and goats (n = 5) followed identical study protocols, which involved a two-phase, single-dose (2 mg/kg), cross-over study design with a one-week washout period between treatments. Blood samples were collected over 24 h for analysis. High-performance liquid chromatography (HPLC) was employed for plasma drug quantification. The analytical method exhibited excellent linearity, recovery, and precision. MTZ exhibited relatively rapid elimination in both animal species, notably faster in goats. Goats have shown a significantly higher clearance rate and consequently lower AUC values. This underscores the importance of considering species-specific differences in drug metabolism and clearance when prescribing medications for small ruminants. Recognizing the pivotal role of AUC/MIC in predicting MTZ efficacy, a dosage adjustment between these two animal species may be necessary to ensure optimal therapeutic outcomes. The bioavailability was relatively high in both animal species, suggesting the potential of SC administration as a practical approach in small ruminants, akin to recent trends in human medicine regarding MTZ administration. Additional research is needed to thoroughly assess the in vivo effectiveness of MTZ in diseased sheep and goats, including PK studies after multiple doses, to establish an appropriate dosing regimen for these animals.

Covalent-Organic Frameworks for Selective and Sensitive Detection of Antibiotics from Water

As the consumption of antibiotics rises, they have generated some negative impacts on organisms and the environment because they are often unable to be effectively degraded, and seeking effective detection methods is currently a challenge. Covalent-organic frameworks (COFs) are new types of crystalline porous crystals created based on the strong covalent interactions between blocked monomers, and COFs demonstrate great potential in the detection of antibiotics from aqueous solutions because of their large surface area, adjustable porosity, recyclability, and predictable structure. This review aims to present state-of-the-art insights into COFs (properties, classification, synthesis methods, and functionalization). The key mechanisms for the detection of antibiotics and the application performance of COFs in the detection of antibiotics from water are also discussed, followed by the challenges and opportunities for COFs in future research.

The Subcutaneous Administration of Beta-Lactams: A Case Report and Literary Review-To Do Small Things in a Great Way

The subcutaneous (s.c.) route is a commonly used method for delivering various drugs, although its application in the administration of antibiotics is relatively uncommon. In this case, we report a successful treatment of nosocomial pneumonia using piperacillin/tazobactam via continuous subcutaneous administration. Furthermore, this article provides an overview of the current literature regarding the s.c. administration of beta-lactam antibiotics. Based on our analysis, we identified only 15 studies that described the s.c. use of beta-lactam antibiotics in human subjects. Among these studies, cephalosporins were the most extensively investigated antibiotic class, with 10 available studies. According to the study findings, all three antibiotic classes (cephalosporins, penicillins, and carbapenems) demonstrated a similar pharmacokinetic profile when administered via the subcutaneous route. The subcutaneous route appears to be associated with a lower peak serum concentration (Cmax) but a comparable minimum blood concentration (Cmin) and an extended half-life (t1/2) when compared to conventional routes of antibiotic administration. Further research is necessary to determine whether subcutaneously administered beta-lactam antibiotics in human subjects achieve pharmacodynamic targets and demonstrate clinical efficacy.

Exploring the advancements of Australian OPAT

Outpatient parenteral antimicrobial therapy (OPAT) in Australia has evolved from modest beginnings to a well-established health service with proven benefits in patient outcomes. This is a comprehensive review of the current state of art Australian OPAT with vignettes of the types of OPAT models of care, antimicrobial prescribing and antimicrobial use. In addition, we highlight the similarities and differences between OPAT to other countries and describe Australian OPAT experiences with COVID-19 and paediatrics. Australian OPAT continues to advance with OPAT antifungals, novel treatment options and upcoming high-impact research.