Impact of pharmaceutical dosage forms on the pharmacokinetics of roxithromycin in healthy human volunteers

Fast dissolving nanofiber mat for the local antimicrobial application of roxithromycin in oral cavity

Fast disintegrating and dissolving nanofiber (NF) mat was devised to deliver roxithromycin for the treatment of the respiratory tract infection. NF membrane was made by an electrospinning process with poly(vinyl alcohol) (PVA), hydroxypropyl-β-cyclodextrin (HP-β-CD), and d-α-tocopheryl polyethylene glycol succinate (TPGS) for local application of roxithromycin. Roxithromycin has a poor water solubility thus HP-β-CD is introduced for enhancing drug solubility by forming an inclusion complex in this study. The addition of TPGS provided multiple roles such as accelerating wetting, disintegration, and dissolution speed and overcoming bacterial resistance. Roxithromycin was successfully entrapped in NF structure and drug amorphization occurred during the electrospinning process. PVA/HP-β-CD/TPGS/roxithromycin (PHTR) NF exhibited faster wetting, disintegration, and dissolution speed rather than the other NF mats. PHTR NF displayed higher antibacterial potentials in Gram-negative bacteria (E. coli) and Gram-positive bacteria (S. aureus) compared to other NF mat formulations. The administration of PHTR NF to oral cavity in pneumococcal disease mouse model provided the most efficient therapeutic potentials in lung tissue. Designed multiple phase-based NF mat may be one of powerful local drug delivery systems for the therapy of respiratory tract infection.

Supercritical Extraction Process of Allspice Essential Oil

Allspice essential oil was extracted with supercritical carbon dioxide (SC-CO2) in a static process at three different temperatures (308.15, 313.15, and 318.15 K) and four levels of pressure (100, 200, 300, and 360 bar). The amount of oil extracted was measured at intervals of 1, 2, 3, 4, 5, and 6 h; the most extraction yield reached was of 68.47% at 318.15 K, 360 bar, and 6 h of contact time. In this supercritical extraction process, the distribution coefficient (KD), the mean effective diffusion coefficient (Def), the energy of activation (Ea), the thermodynamic properties (ΔG0, ΔH0, and ΔS0), and the apparent solubility (S) expressed as mass fraction (w/w) were evaluated for the first time. At the equilibrium the experimental apparent solubility data were successfully correlated with the modified Chrastil equation.

Impact of pharmaceutical dosage form on stability and dissolution of roxithromycin

The behavior of dispersible tablets containing enteric-coated pellets and oral suspension, both containing roxithromycin, was investigated using dissolution tests in different media. The dissolution test was performed under different pH conditions. For both dosage forms investigated, the test was conducted at pH 1.2, 4.5, and 6.8. Additionally, for dispersible tablets, the test involving increasing pH was performed at pH 1.2 (acid stage) and afterwards at pH 6.8 (buffer stage). The extent of dissolution was measured using high-performance liquid chromatography (HPLC). In all cases tested, roxithromycin underwent rapid degradation at pH 1.2. Dispersible tablets displayed the features of modified release preparations with a non-complete dissolution during the test times in all media. Conversely, the oral suspension behaved as an immediate release preparation, with degradation at pH 1.2. However, the dissolution of the oral suspension at pH 4.5 and 6.8 was rapid and complete. The role of enteric-coated pellets is to mask the bitter taste of the active substance upon administration. However, the coating showed lack of resistance to media at pH 1.2. Therefore, dispersible tablets containing enteric-coated pellets are not pharmaceutically equivalent to the immediate-release oral suspension.