Lack of Effect of Simultaneously Administered Didanosine Encapsulated Enteric Bead Formulation (Videx EC) on Oral Absorption of Indinavir, Ketoconazole, or Ciprofloxacin

Abstract

Didanosine formulation that contains a buffer to prevent it from acid-mediated degradation can result in a significant decrease in the oral absorption of certain drugs because of interactions with antacids. An enteric formulation of didanosine is unlikely to cause such drug interactions because it lacks antacids. This study was undertaken to determine whether the enteric bead formulation of didanosine (Videx EC) , 1.08), respectively. All three studies clearly indicated a lack of interaction. The T max and t 1/2 for indinavir, ketoconazole, and ciprofloxacin were similar between treatments. Our results showed that the lack of interaction of didanosine encapsulated enteric bead formulation with indinavir, ketoconazole, and ciprofloxacin indicates that this enteric formulation of didanosine can be concomitantly administered with drugs whose bioavailability is known to be reduced by interaction with antacids.

Selection and Characterization of Suitable Lipid Excipients for use in the Manufacture of Didanosine-Loaded Solid Lipid Nanoparticles and Nanostructured Lipid Carriers

“…12 Videx R EC eliminates the concomitant use of buffers and/or antacids to ensure DDI bioavailability and therefore may be a better dosage form for the oral administration of DDI. 13 However, Videx R EC capsules must only be swallowed whole. 12 Although children older than 3 years may be switched from a liquid to a solid oral dosage form in certain conditions, relatively young pediatric patients must continue to use DDI formulations that contain buffers or antacids.…”

HIV Infection and Multidrug‐Resistant Tuberculosis—The Perfect Storm

“…Furthermore, overlapping toxicities and interactions between anti-TB and antiretroviral drugs complicate treatment [118][119][120][121][122]. Overlapping toxicities include peripheral neuropathy (stavudine, didanosine, and ethambutol), hepatotoxicity (nevirapine, efavirenz, and pyrazinamide), rash (abacavir, amprenavir, nevirapine, efavirenz, fosamprenavir, and pyrazinamide), and ocular effects (didanosine and ethambutol), among others [118][119][120][121][122]. Beyond the known interactions between rifamycins and multiple antiretroviral medications, drug interactions of concern for HIV-infected patients with MDR-TB include the buffered tablet formulation of didanosine and quinolones.…”

“…Beyond the known interactions between rifamycins and multiple antiretroviral medications, drug interactions of concern for HIV-infected patients with MDR-TB include the buffered tablet formulation of didanosine and quinolones. The buffer binds fluoroquinolones (as do antacids) and blocks gastrointestinal absorption [118][119][120][121][122].…”

Drug Interactions Between Antiretroviral Drugs and Comedicated Agents

“…[76] This type of drug interaction can easily be avoided by separation of drug administration. Alternatively, the new, enteric-coated formulation of DDI, [21,126] which lacks the buffer, could be used.…”