Chitosan microencapsulation of the dispersed phase of an O/W nanoemulsion to hydrochlorothiazide delivery.

In view of biopharmaceutical limitations of hydrochlorothiazide (HCTZ), Trojan-type mucoadhesive systems were proposed, aiming to improve HCTZ pharmacological properties by modulating its release. Nanoemulsions were formed spontaneously by combining medium-chain triglycerides (Lipoid S75 and Pluronic F68) and high encapsulation efficiency was obtained. The mucoadhesive properties were provided by chitosan and microencapsulation of nanoemulsions in spray-dryer was successfully achieved by using Aerosil as wall material.

Self-Nanoemulsified Drug Delivery System of Hydrochlorothiazide for Increasing Dissolution Rate and Diuretic Activity.

Hydrochlorothiazide (HCTZ) is a class IV drug according to the Biopharmaceutical Classification System. This study aimed the development of self-nanoemulsifying drug delivery system (SNEDDS) for HCTZ as an approach to overcome the biopharmaceutical limitations. Pre-formulation screening and ternary phase diagrams were carried out to select the oil phase, the surfactant, and the co-surfactant as the amount of each constituent.

Inclusion complexes of hydrochlorothiazide and β-cyclodextrin: Physicochemical characteristics, in vitro and in vivo studies.

Hydrochlorothiazide is a thiazide diuretic widely used in clinics to treat arterial hypertension. It is a class IV drug according to the Biopharmaceutical Classification System, that is, it presents low solubility and low permeability and, consequently, low absorption in the gastrointestinal tract. As a strategy to improve stability and biopharmaceutical properties of hydrochlorothiazide, the use of cyclodextrins to produce inclusion complexes, applying different methods, was investigated.

Quantitative Analysis of Norfloxacin in β-Cyclodextrin Inclusion Complexes--Development and Validation of a Stability-indicating HPLC Method.

The aim of this study was to develop and validate a simple liquid-chromatography method, with good accuracy, reproducibility and sensitivity, for the quantification of norfloxacin in β-cyclodextrin inclusion complexes. In the method validation, the parameters evaluated were linearity, limits of detection and quantification, specificity, accuracy, precision and robustness. The stability-indication property of the method was evaluated through studies on the degradation under stress conditions.

Investigation of β-cyclodextrin-norfloxacin inclusion complexes. Part 2. Inclusion mode and stability studies.

Introduction: Norfloxacin (NFX) is a broad spectrum antibiotic with low solubility and permeability, which is unstable on exposure to light and humidity.

Objective: In this study, the mode of NFX inclusion into β-cyclodextrin complexes was evaluated and a complete physical, chemical and microbiological stability study of the inclusion complexes was carried out.

Methods: Potentiometric titrations were performed to evaluate changes in the pKa of the NFX molecule due to the formation of an inclusion complex and NMR analysis demonstrated that the NFX molecule is included in the β-cyclodextrin cavity.

Investigation of β-cyclodextrin-norfloxacin inclusion complexes. Part 1. Preparation, physicochemical and microbiological characterization.

Introduction: Drugs classified as class IV by the Biopharmaceutical Classification System present significant problems in relation to effective oral administration. In the case of antibiotics, the subsequently high doses required can enhance the emergence of microorganism resistance and lead to a low rate of patient treatment adherence.

Objective: In an attempt to improve physicochemical properties and microbiological activity of norfloxacin, the aim of this study was to investigate different methods (coevaporation, kneading followed by freeze-drying or spray-drying) to obtain complexes of norfloxacin and different cyclodextrins.