Release of rifampicin from nanoparticles Sample Clauses

Release of rifampicin from nanoparticles. To characterize rifampicin release from the lipid shell nanoparticles, the drug remaining in the carrierswith and without prior exposure to shell permeabiliser Pluronic L62D was measured. When the lipid nanoparticle permeabliser was used it was mixed with the purified nanoparticle suspensions at a Pluronic: nanoparticle ratio of 1:0.5 w/w. The release of the lipid shell nanoparticles was determined by dialyzing the nanoparticle suspensions against PBS buffer (1.6 mg nanoparticle per mL buffer) either at pH 7.4 and 4.2, 37°C. For the PVA shell nanoparticles without the shell permeabiliser the suspensions generated by the manufacture method were mixed with PBS pH 7.4 in a 1:1 v/v and the drug release determined by dialysis. To permeabilise the PVA shell nanoparticles PBS pH 4.2 buffer was added to nanoparticle suspension in a 1:1 v/v and the mixture was transferred to a dialysis sac and dialysed against 500 mL of PBS buffer at either pH 7.4 or pH 4.2 to determine the drug release. The rifampicin solubility was measured to be 1550 μg/mL at pH 7.4 and 750 μg/mL at pH 4.2 and therefore sink conditions were maintained in all the release experiments (total loading per 500 mL was ca. 1.2 mg). To monitor the drug release from all the nanoparticle experiments 0.5 ml aliquots were removed from dialysis the tubing containing the suspensions (12-14 kDa molecular weight cut off) at a series of pre-determined time points and rifampicin content in the nanoparticles was measured by HPLC (as detailed in the loading assessment method). The drug content remaining in the nanoparticles was calculated according to Equation 2.3: Release (%) = M0 – Mt M0 Equation 2.3 Where M0 was the mass of drug in nanoparticleat t0 and Mt was the mass of drug in nanoparticle at a time point.