A promising approach to provide appropriate colon target drug delivery systems of vancomycin HCL: pharmaceutical and microbiological studies

Preparation and evaluation of antibacterial wound dressing based on vancomycin-loaded silk/dialdehyde starch nanoparticles

One of the main reasons infected wounds go untreated is that antibiotic-resistant bacteria mainly cause infection. Vancomycin is an antibiotic used against Gram-positive bacteria, such as MRSA, but it has limited intravenous use due to its toxicity. This study describes using a local drug delivery approach at the wound site. The aim is to prepare a silk dressing containing dialdehyde starch nanoparticles loaded with vancomycin that can cure infection through the controlled release of antibiotics. First, the starch was oxidized by sodium periodate solution and converted to dialdehyde starch. Dialdehyde starch was converted into nanoparticles by the microemulsion method. Simultaneously, with nanoparticle formation, the antibiotic vancomycin (VAN), added to the solution, was loaded into the dialdehyde starch nanoparticles (DASNP). The wound dressing (SF/DASNP/VAN) was prepared by adding nanoparticles containing antibiotics to the silk fibroin (SF) solution, and then, the solution containing the nanoparticles was freeze-dried, and the nanoparticles were placed inside the silk matrix. Drug release of dressings was performed by immersion in phosphate-buffered saline, and cytotoxicity by MTT assay and antibacterial properties of dressings were investigated by the inhibition zone method. The morphology of the SF/DASNP/VAN dressing, its biocompatibility, antibacterial efficiency, and antibiotic release kinetics were assessed. The synthesized dressing has the desired biocompatibility with 69% cell viability and shows antibacterial properties against MRSA with a growth inhibition zone diameter of 12 mm. Also, VAN was successfully incorporated into the dressing, resulting in a 144-h continuous release profile. It may be concluded that the fabricated dressing based on silk and dialdehyde starch nanoparticles opens up a new option for topical administration of antibiotics. We believe its properties can be considered a new dressing for infectious wounds by reducing infection associated with controlled drug delivery.

Serum and Synovial Vancomycin Concentrations in Patients with Prosthetic Joint Infection after Intra-articular Infusion

BACKGROUND AND OBJECTIVES

Vancomycin is one of the most commonly used antibiotics for intra-articular (IA) infusion in the treatment of prosthetic joint infection (PJI). This study aimed to preliminarily investigate the serum and synovial vancomycin concentrations in patients with PJI after IA infusion.

METHODS

In total, 16 patients who developed PJI were enrolled in this study; 14 of the patients were treated with IA infusion of vancomycin postoperatively, while the other 2 patients received intravenous (IV) infusion of vancomycin alone. Chemiluminescent immunoassay assay (CLIA) and high-performance liquid chromatography (HPLC) were used to determine the serum and synovial vancomycin concentrations, respectively.

RESULTS

Administration of vancomycin 0.5 g once daily (qd) IA maintained a high vancomycin trough concentration in synovial fluid before the next IA dose, regardless of whether it was given in combination with IV administration. The combination vancomycin 0.5 g qd IA + vancomycin 1 g every 12 h (q12h) IV yielded relatively good trough concentrations of vancomycin in both serum and synovial fluid. The mean trough serum vancomycin concentration of patients who used vancomycin 1 g q12h IV therapy was above 10 μg/mL; however, no vancomycin was detected in their synovial fluid.

CONCLUSIONS

The rational use of IA vancomycin infusion may help to achieve effective therapeutic concentrations of vancomycin in the serum and synovial fluid of patients with PJI.

Transdermal delivery of vancomycin hydrochloride: Influence of chemical and physical permeation enhancers

Topical and transdermal delivery of vancomycin hydrochloride (VH), a broad-spectrum peptide antibiotic, is a challenge because of its high molecular weight (1485.7 Da) and hydrophilicity (log P -3.1). The objective of this study was to investigate the feasibility of delivering VH into and across the skin using permeation enhancement techniques. Skin permeation studies were performed using Franz diffusion cell apparatus in the excised porcine skin model. The influence of co-treatment and pre-treatment of chemical permeation enhancers (oleic acid and palmitic acid) on permeation of VH across intact and tape-stripped skin was evaluated. In addition, continuous anodal iontophoresis was applied to enhance the skin permeation of VH. The mechanism of skin permeation enhancement by palmitic acid was investigated using FTIR spectroscopy, impedance spectroscopy, and thermal analysis techniques. Pharmacokinetic analysis was performed after the topical application of VH formulations in Sprague Dawley rats. Results from permeation studies showed that VH did not passively permeate across the intact skin after 48 h, whereas the cumulative amount of VH permeated across the tape-stripped skin was found to be 854 ± 67 µg/cm². A combination of tape-stripping and chemical enhancers resulted in enhancing the cumulative amount of VH permeated across the skin by 2- and 10-fold with oleic acid and palmitic acid application, respectively. Similarly, 2 and 12 h pre-treatment of tape-stripped skin with palmitic acid enhanced the flux of VH across the skin by 1.7- and 5-fold, respectively. It was found that tape-stripping and the palmitic acid application would provide greater VH permeation compared with 0.31 mA/cm² iontophoresis application. Thermal analysis and impedance spectroscopic analysis showed that palmitic acid interacts with epidermal lipids to enhance VH permeation. Pharmacokinetic analysis after topical application showed that the C_max and mean residence time increased by 3-fold with the application of VH and palmitic acid on tape-stripped skin compared with free VH on intact skin. Taken together, VH can be delivered through the topical route using a combination of chemical enhancer and tape-stripping to treat local and systemic bacterial infections.

Fusogenic Liposomes Increase the Antimicrobial Activity of Vancomycin Against Staphylococcus aureus Biofilm

Objective: The aim of the present study was to encapsulate vancomycin in different liposomal formulations and compare the in vitro antimicrobial activity against Staphylococcus aureus biofilms.

Methods: Large unilamellar vesicles of conventional (LUV VAN), fusogenic (LUV_fuso VAN), and cationic (LUV_cat VAN) liposomes encapsulating VAN were characterized in terms of size, polydispersity index, zeta potential, morphology, encapsulation efficiency (%EE) and in vitro release kinetics. The formulations were tested for their Minimum Inhibitory Concentration (MIC) and inhibitory activity on biofilm formation and viability, using methicillin-susceptible S. aureus ATCC 29213 and methicillin-resistant S. aureus ATCC 43300 strains.

Key Findings: LUV VAN showed better %EE (32.5%) and sustained release than LUV_fuso VAN, LUV_cat VAN, and free VAN. The formulations were stable over 180 days at 4°C, except for LUV VAN, which was stable up to 120 days. The MIC values for liposomal formulations and free VAN ranged from 0.78 to 1.56 µg/ml against both tested strains, with no difference in the inhibition of biofilm formation as compared to free VAN. However, when treating mature biofilm, encapsulated LUV_fuso VAN increased the antimicrobial efficacy as compared to the other liposomal formulations and to free VAN, demonstrating a better ability to penetrate the biofilm.

Conclusion: Vancomycin encapsulated in fusogenic liposomes demonstrated enhanced antimicrobial activity against mature S. aureus biofilms.

Exploring Different Strategies for Efficient Delivery of Colorectal Cancer Therapy

Colorectal cancer (CRC) is the third most common cancer and the fourth leading cause of cancer death in the world. Currently available chemotherapy of CRC usually delivers the drug to both normal as well as cancerous tissues, thus leading to numerous undesirable effects. Much emphasis is being laid on the development of effective drug delivery systems for achieving selective delivery of the active moiety at the anticipated site of action with minimized unwanted side effects. Researchers have employed various techniques (dependent on pH, time, pressure and/or bacteria) for targeting drugs directly to the colonic region. On the other hand, systemic drug delivery strategies to specific molecular targets (such as FGFR, EGFR, CD44, EpCAM, CA IX, PPARγ and COX-2) overexpressed by cancerous cells have also been shown to be effective. This review aims to put forth an overview of drug delivery technologies that have been, and may be developed, for the treatment of CRC.

Increased release time of antibiotics from bone allografts through a novel biodegradable coating

The use of bone allografts is contraindicated in septic revision surgery due to the high risk of graft reinfection. Antibiotic release from the graft may solve the problem and these combinations can theoretically be used for prevention or even therapy of infection. The present study investigated whether amoxicillin, ciprofloxacin, and vancomycin alone or in combination with chitosan or alginate are suitable for short-term or long-term bone coating. Human bone allografts were prepared from femoral head and lyophilized. Antibiotic coating was achieved by incubating the grafts in antibiotic solution and freeze-drying again. Two biopolymers chitosan and alginate were used for creating sustained-release implantable coatings and the drug release profile was characterized in vitro by spectrophotometry. Using lyophilization with or without chitosan only resulted in short-term release that lasted up to 48 hours. Alginate coating enabled a sustained release that lasted for 8 days with amoxicillin, 28 days with ciprofloxacin coating, and 50 days with vancomycin coating. Using only implantable biodegradable allograft and polymers, a sustained release of antibiotics was achieved with ciprofloxacin and vancomycin for several weeks. Since the calculated daily release of the antibiotic was lower than the recommended IV dose, the calcium alginate coated bone graft can support endoprosthesis revision surgery.