Development and evaluation of dapsone tablets coated for specific colon release.

Objective: Drug release systems based on colonic microbiota have been explored with the use of polysaccharides, which are biodegradable. In order to modulate the release into the colon, dapsone tablets were developed, coated with Surelease® and chondroitin sulfate (SC).Methods: The formulation was developed using the wet granulation method, in the form of 9-millimetre circular tablets. The coating was applied in a perforated basin-type coating using different proportions of Surelease® and chondroitin sulfate. The tablets were assessed according to the criteria of mean weight, hardness, and friability. The dissolution test was performed in the dissolver IV apparatus, in media simulating the gastrointestinal system environments (pH 1.2-pH 6.0 and pH 7.2) for 420 min. The results were analyzed by statistical analysis and factorial design.Results: The results of mean weight, hardness, and friability met the pharmacopeial specifications. In the dissolution test, the results obtained demonstrated that Surelease® is able to offer effective protection to the drug, releasing minimum rates when used at 6% or 10% of the tablet's weight gain. The experiments showed that the drug was not able to spread through the coatings manufactured exclusively with Surelease® or even when SC was incorporated in different proportions. Only in the formulation where SC was included in the highest proportion (10%), and the weight gain of the tablet was lower (6%), the release of dapsone increased, reaching 9.5% of drug released. Through factorial planning, it was observed that the drug release rate increases when the weight gain of the tablet remains at the lower level (6%), while the amount of polysaccharide is increased (90:10).Conclusions: The data indicate that the proportion of polysaccharide for ethyl cellulose in the film and the thickness of the coating are the key parameters in controlling the release of the drug from the system.

α-Gluco-oligosaccharide in the research and development of a polymeric material for modified drug delivery.

This research aimed to analyse the influence of the incorporation of α-gluco-oligosaccharide (GOS-α) in the formation of isolated films of different combinations of polymethyl by applying physicochemical analyses such as Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG) and scanning electron microscopy (SEM). Polymer films were prepared by evaporation associating Eudragit® RS30D with α-GOS. FTIR results confirmed the incorporation of α-GOS. The intermolecular interaction involving carbonyl and hydroxyl groups of Eudragit® with α-GOS was not detected. By TG and DSC, it was possible to detect that there were no changes in the thermal properties between the proposed combinations and the standard film. Upon SEM analysis, the appearance of pores for the association 90:10 was evidenced. Possibly, these pores act as output ports for the drug. These results sharpen the perspective of applying this material to the coating of pharmaceutical formulations of modified drug delivery.

Development and characterization of lipid-polymeric nanoparticles for oral insulin delivery.

INTRODUCTION: The oral route is widely accepted as the most physiological path for exogenous administration of insulin, as it closely mimic the endogenous insulin pathway. Thus, in this work it is proposed an innovative lipid-polymeric nanocarrier to delivery insulin orally. Areas covered: Nanoparticles were produced through a modified solvent emulsification-evaporation method, using ethyl palmitate and hydroxypropylmethylcellulose acetate succinate as matrix. Lipid-polymeric nanoparticles were around 300 nm in size, negatively charged (-20 mV) and associated insulin with efficiency higher than 80%. Differential scanning calorimetry suggested thermal stability of nanoparticles. In vitro release assays under simulated gastrointestinal conditions resulted in 9% and 14% of insulin released at pH 1.2 during 2 h and at pH 6.8 for 6 h, respectively, demonstrating the ability of those nanoparticles to protect insulin against premature degradation. Importantly, nanoparticles were observed to be safe at potential therapeutic concentrations as did not originate cytotoxicity to intestinal epithelial cells. Lastly, the permeability of nanoencapsulated insulin through Caco-2 monolayers and a triple Caco-2/HT29-MTX/Raji B cell model correlated well with slow release kinetics, and fosters the effectiveness of nanoparticles to promote intestinal absorption of peptidic drugs. Expert opinion: Lipid-polymeric nanoparticles were developed to encapsulate and carry insulin through intestine. Overall, nanoparticles provide insulin stability and intestinal permeability.

Exploitation of lipid-polymeric matrices at nanoscale for drug delivery applications.

INTRODUCTION: Progress in drug delivery and a better quality of life for patients, relies on the development of new and suitable drug carrier systems, with unequivocal therapeutic benefits, low systemic toxicity and reduced side effects. Lipid-polymeric nanoparticles have been explored to produce nanocarriers due to their features and applications such as high drug entrapment, physical-chemical stability and controlled release properties. AREAS COVERED: In this review, we describe several hybrid nanoparticles obtained from mixing a polymer with a lipid matrix. This association can potentiate the efficacy of drug delivery systems, due to the enhancement of encapsulation efficiency and loading capacity, tailoring the drug release according to the therapeutic purpose, and improving the drug uptake by targeting it to specific receptors. Contrary to lipid nanoparticles, these hybrid nanoparticles can decrease the initial burst release and promote a more sustained and localized release of the drug. EXPERT OPINION: Lipid-polymeric nanoparticles are versatile vehicles for drug delivery by different administration routes in the treatment of multiple diseases. Different solid lipids, polymers, surfactants and techniques for producing these carriers have been investigated, revealing the importance of their composition to achieve optimal characteristics to drug delivery.

Eudragit ® FS 30 D polymeric films containing chondroitin sulfate as candidates for use in coating seeking modified delivery of drugs

ABSTRACT Polymeric films associating different concentrations of Eudragit(r) FS 30 D (EFS) and chondroitin sulfate (CS) were produced by casting for the development of a new target-specific site material. Formed films kept a final polymer mass of 4% (w/v) in the following proportions: EFS 100:00 CS (control), EFS 95:05 CS, EFS 90:10 CS and EFS 80:20 CS. They were analyzed for physical and chemical characteristics using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Raman spectroscopy. Furthermore, they were characterized by their water vapor permeability and degree of hydration at different conditions simulating the gastrointestinal tract. No chemical interactions were observed between CS and EFS, suggesting only a physical interaction between them in the different combinations tested. The results suggest that EFS and CS, when combined, may form films that are candidates for coating processes seeking a modified drug delivery, especially due to the synergism between pH dependency and specific biodegradability properties by the colonic microbiota. EFS 90:10 CS proved to be the most suitable for this purpose considering hydration and permeability characteristics of different associations analyzed.