Increasing doxycycline hyclate photostability by complexation with ß-cyclodextrin.

Doxycycline hyclate (DOX) is a highly photosensitive drug, a feature that limits the stability of the corresponding dosage forms. The main objectives of this work were the preparation and characterization of an inclusion complex of DOX with ß-cyclodextrin (ßCD) and to investigate if this approach could improve the photostability of the drug. Guest-host interactions were investigated using nuclear magnetic resonance, which were afterwards combined with molecular modeling methods to study the complex formation and its three-dimensional structure was proposed. A freeze-drying method was applied to obtain the complex in the solid state, which was further confirmed by thermal and spectroscopic techniques. To evaluate the complexation effect on DOX integrity, the photostability of the inclusion complex was studied, with a significant decrease in the photodegradation of DOX being found in aqueous solution upon complexation. Finally, the photoprotection produced by the complexation was evaluated by means of an antimicrobial assay. Overall, the presented results suggest that the formulation of DOX complexed with ßCD constitutes an interesting approach for the preparation of pharmaceutical dosage forms of DOX with enhanced stability properties.

Darunavir: a critical review of its properties, use and drug interactions.

Darunavir is a synthetic nonpeptidic protease inhibitor which has been shown to be extremely potent against wild-type HIV as well as a large panel of PI-resistant clinical isolates and shows a high genetic barrier to the development of antiretroviral resistance. The treatment of HIV/AIDS requires combinations of multiple antiretroviral drugs. In addition, patients frequently need to coadminister other medications for reasons including the prevention or treatment of opportunistic infections, treatment of concomitant illnesses and management of antiretroviral side effects. Drug interactions have been observed between darunavir and other drugs. New and more comprehensive drug interaction studies will be required since the increase in life expectancy of patients often brings new comorbidities and the concomitant use of different drugs. This paper discusses the impact of the use of darunavir in the treatment of HIV-infected patients, its pharmacological and physical-chemical properties, its drug interactions, and challenges that remain in order to ensure safety and compliance of treatment.

Tigecycline: a review of properties, applications, and analytical methods.

Tigecycline is a new glycylcycline with an expanded broad-spectrum antibiotic, including inhibition of Gram-positive, Gram-negative, atypical, anaerobic, and antibiotic-resistant organisms. Trials have demonstrated that tigecycline is noninferior to the comparators for the treatment of complicated skin and skin structure infections as well as complicated intra-abdominal infections. Tigecycline is only available as an intravenous preparation and analytical methods to its quantitation in pharmaceutical products has not been published to date. This review examined tigecycline characteristics, the spectrum and mechanism of action, pharmacokinetics, applications, and, mainly, the instrumental conditions of published chromatographic methods used to measure tigecycline, its metabolites, and some analogs in clinical and biologic research.

ß-cyclodextrin complexation as an approach to enhance the biopharmaceutical properties of Norfloxacin B Hydrate.

Binary systems of Norfloxacin B Hydrate with ß-CD were explored by reliable biopharmaceutical studies as potential candidates for the preparation of drug delivery systems. Initially, studies of antimicrobial activity and solubility of the different polymorphic forms of Norfloxacin provided evidence to select Norfloxacin B Hydrate as the optimal solid form of Norfloxacin. Solid binary systems were preparing by kneading, freeze-drying, and physical mixture methods. The influence on the solubility, dissolution rate and chemical stability of Norfloxacin B Hydrate was investigated. These studies showed an increment of solubility and dissolution rate in physiological simulated fluids. However, the solid systems were moderated hygroscopically under accelerated storage conditions, which produces a destabilizing effect that accelerated the chemical reactivity of the drug in such conditions. Therefore, special cares must be considered in the manufacturing process and the packaging selection. Moreover, the experimental results proved that freeze-drying was not an appropriate method for the preparation. In conclusion, the Norfloxacin oral bioavailability can be improved with this binary systems, that could be applied in the production of an alternative pharmaceutical formulation of the drug.