ENHANCING ORAL BIOAVAILABILITY OF FAMOTIDINE AND ROXITHROMYCIN (BCS-IV DRUGS) BY NANO-EMULSIFYING DRUG DELIVERY SYSTEM

Abstract

Pre-dosage forms of Famotidine and Roxithromycin available in the market suggest that their treatment may not facilitate patients due to poor water solubility and permeability which ultimately leads to their low oral bioavailability. To reduce the draw backs associated with their systemic administration, Solid Lipid Nanoparticles (SLNs) loaded with Famotidine and Roxithromycin were fabricated as a mean of achieving boosted oral bioavailability. During fabrication of Solid Lipid Particles (SLNs), emulsion was employed as the most important precursor. Stearic acid was employd as the solid lipid phase and Tween® 80 as surfactant. Polyethylene glycol and polyvinyl alcohol were used as co-surfactants. Different results in term of particles size and polydispersity index (PDI) were obtained by varying experimental conditions, i.e. concentration of surfactant, concentration of co-surfactant and stirring time. SLNs were fabricated via three different techniques (Solvent Injection, Solvent Emulsification Evaporation and Hot Melt Encapsulation) using nano-template engineering technology. Solvent Injection technique was employed for Fabrication of SLNs loaded with Roxithromycin and Famotidine. SLNs loaded with Roxithromycin and Famotidine demonstrated particle size 169.6±2.3 nm & 162.7±2.3 nm, PDI 0.462±0.02 & 0.352±0.03, zeta potential -32.6±1.9 mV & -34.35±2 mV, percent entrapment efficiency 84.36±1.3% & 85±2.7%, percent drug loading capacity 2.709±0.43% & 2.74±0.33% respectively. Solvent Emulsification Evaporation method being used for preparation of SLNs loaded with Roxithromycin and Famotidine. SLNs loaded with Roxithromycin and Famotidine showed particle size 126.27±2.1 nm & 111.9±1.3 nm, PDI 0.435±0.01 & 0.464±0.03, zeta potential -36.72±2 mV & -33.46±2 mV, percent entrapment efficiency 83.61±2.3% & 84±2.7%, percent drug loading capacity 2.677±0.13% & 2.709±0.13% respectively. Hot Melt Encapsulation technique, which avoids the use of organic solvent was also being employed for Fabrication of SLNs loaded with Roxithromycin and Famotidine. SLNs loaded with Roxithromycin and Famotidine demonstrated particle size 179.7±2.3 nm & 174.8±2.1 nm, PDI 0.424±0.03 & 0.419, zeta potential -38.16±1.6 mV & -36.35 mV, percent entrapment efficiency 86% & 87±2.1%, percent drug loading capacity 2.77% & 2.81±0.13% respectively. During further characterization of loaded SLNs formulations, the white patches in the micrographs of Scanning Electron Spectroscopy (SEM) verified identical, spherical shaped and nano-metric size particles. SEM also showed that the particles size was in concordance to the data attained from Dynamic Light Scattering analysis. Fourier Transform Infrared Spectroscopy revealed no drugs-excipients interaction. Moreover, characterization via using Powdered X-Ray Diffractometer and Differential Scanning Calorimetry confirmed successful reduction in the crystalline nature of the loaded SLNs formulations. In-vitro drug release study was conducted and enhanced sustained release was found with maximum drug pay-load. Different mathematical kinetic models were employed to the drug release data to confirm the drug release kinetics and mechanism. During stability study, SLN dispersions stored at different conditions confirmed maximum stability at refrigerated condition, showing a consistent particles size and polydispersity. Moreover, tray drying technique as alternative to lyophilization was investigated and found that this technique can also be employed for SLNs drying purpose, especially for bulk production. Scanning Electron Microscopy (SEM) was conducted for the samples being prepared by tray drying technique in order to compare with the lyophilized samples, the white patches in the micrographs of both samples were almost similar in size and shape. To acquire proper solid dosage form, loaded SLNs nano-suspensions were processed to obtain dried powder followed by conversion to granules and consequently filled in capsule shells. Comparative in-vitro study of the prepared capsules was conducted for dissimilarity (f1) and similarity (f2) factors determination. Dissimilarity factor greater than 65 (f1>65) showing a remarked difference compared to the marketed products. Comparative in-vivo study of the SLNs nano-suspension as well as prepared capsules with the marketed product has also been conducted. This study showed massive difference, in terms of increased Cmax as well as AUC0→24 compared to the marketed products. Overall, these results indicate that the developed Nanoparticulate Drug Delivery System of SLNs is smart enough showing significantly improved oral bilavailability with sustained drug release profile for Famotidine and Roxithromycin.