Bioavailability of Oral Hydrocortisone Corrected for Binding Proteins and Measured by LC-MS/MS Using Serum Cortisol and Salivary Cortisone
Narendar Dudhipala, Arjun Narala, Karthik Yadav Janga and Ramesh Bomma
The aim of the present investigation was to formulate and evaluate floating-bioadhesive tablets of amoxicillin trihydrate (ATFBT), to provide local action in the treatment of Helicobacter pylori (H. pylori) by prolonging the gastric residence time. The FBT were prepared by direct compression method using hydroxy propyl methyl cellulose (HPMC K4M) / chitosan (CH), carbopol (CP974P) / polymethacrylic acid (PMA) as release retarding agent / bioadhesive respectively, sodium bicarbonate (NaHCO3) as a gas-former. The prepared tablets were evaluated for their physical characters such as drug content, in vitro buoyancy, swelling index, drug release and stability. Further, the bioadhesive strength (BS) was determined using porcine gastric mucosa. DSC studies indicate the compatibility of the drug and excipients used in the formulation. The floating lag time, total floating time, bioadhesive strength and swelling index of the optimized formulation (F7) was 32 ± 2.7 sec, more than 12 h, 1.86 ± 0.14 N and more than 3.5 respectively. Formulation (F7) was also found to be physically stable when stored at 40ºC / 75% RH for 3 months. The drug release profiles of all the formulations were fitted into various kinetic models. The optimized formulation followed the Peppas model (r2 > 0.99) with a non-Fickian diffusion mechanism (n = 0.625). From the results, a matrix floatingbioadhesive tablet incorporating an insoluble active substance such as amoxicillin trihydrate was developed for the successful eradication of H. pylori.