Collaterally Sensitive ß-Lactam Drugs as an Effective Therapy against the Pre-Existing Methicillin Resistant Staphylococcus aureus (MRSA) Biofilms.

Methicillin-resistant Staphylococcus aureus (MRSA) is among the leading causes of nosocomial infections and forms biofilms, which are difficult to eradicate because of their increasing resistance to antimicrobial agents. This is especially true for pre-existing biofilms. The current study focused on evaluating the efficacy of three ß-lactam drugs, meropenem, piperacillin, and tazobactam, alone and in combination against the MRSA biofilms. When used individually, none of the drugs exhibited significant antibacterial activity against MRSA in a planktonic state. At the same time, the combination of meropenem, piperacillin, and tazobactam showed a 41.7 and 41.3% reduction in planktonic bacterial cell growth, respectively. These drugs were further assessed for biofilm inhibition and removal. The combination of meropenem, piperacillin, and tazobactam caused 44.3% biofilm inhibition, while the rest of the combinations did not show any significant effects. Results also revealed that piperacillin and tazobactam exhibited the best synergy against the pre-formed biofilm of MRSA, with 46% removal. However, adding meropenem to the piperacillin and tazobactam combination showed a slightly reduced activity towards the pre-formed biofilm of MRSA and removed 38.7% of it. Although the mechanism of synergism is not fully understood, our findings suggest that these three ß-lactam drugs can be used in combination as very effective therapeutic agents for the treatment of pre-existing MRSA biofilms. The in vivo experiments on the antibiofilm activity of these drugs will pave the way for applying such synergistic combinations to clinics.

Optimization and validation of an analytical method for the estimation of methotrexate in rabbit plasma.

Methotrexate (MTX) is an anticancer drug used for the treatment of various cancers and autoimmune diseases. In this study, High Performance Liquid Chromatography (HPLC) method was developed and validated for the estimation of MTX in rabbit plasma with high estimation rate and recovery. Various validation parameters like, sensitivity, sample recovery, accuracy and precision analysis were studied. The pre-saturated reversed C18 end capped HPLC column was used to separate MTX present in rabbit plasma. A solvent mixture of 100mM phosphate buffer pH 7.4 and acetonitrile (92:8 percent v/v) was employed as the mobile phase. Analysis was carried out at ʎ max 303 nm and retention time of MTX was found 5.32 min. During the method development and validation ICHQ2 (R1) guidelines were strictly followed. Developed method was found excellent in terms of recovery of MTX from plasma samples (98.6%). It is obvious from the current study that the developed HPLC method can be utilized to analyze the level of MTX in patients. Furthermore, the cost of the developed method for the determination of MTX would be very low as compared to the previously reported methods.

Development, characterization and optimization of methotrexate-olive oil nano-emulsion for topical application.

The chronic inflammatory conditions like psoriasis has an increased prevalence and is linked with various associated life threatening disease conditions. The main objective of this project was to developed a methotrexate-olive loaded nano emulsion. The formulation was assessed for various parameters including Thermodynamic Stability, physico-chemically characterization, drug release kinetics and entrapment efficiency and in vitro/ in vivo skin permeation analysis. Final optimized formulation had a particle size 18.27±5.78 nm with a PDI of 0.25±0.01, whereas the average entrapment efficiency of formulation was 74.68±2.1%. The release kinetics suggested 97.72% drug release at pH 5 after 20 hrs. The FTIR data confirmed that the chemical structure of drug is retained with efficient loading into the formulation. Permeation data showed that an average of 79.23±3.6µg/cm2 of methotrexate was permeated from the nano emulsion with an average flux of 2.326±0.45µg/cm2/h after 24 hrs. Finally in vivo studies on rabbit skin confirmed that the structural changes of intercellular lipid layers in the stratum corneum are not responsible for enhanced skin permeation of methotrexate loaded nano emulsion. It was concluded that olive oil based MTX-NE is suitable for topical application and can be used for management of psoriasis.