Maria Cristina Tiralti

Intercalation compounds of hydrotalcite-like anionic clays with anti-inflammatory agents, II: Uptake of diclofenac for a controlled release formulation

The purpose of this study was to investigate whether hydrotalcite is able to intercalate diclofenac, a nonsteroidal anti-inflammatory drug, and release it in a controlled manner. Layered Mg−Al hydrotalcite in the chloride form was used as a host, and the intercalation compound was prepared by Cl−/diclofenac anionic exchange. Drug release from the intercalation compound was performed in vitro in simulated intestinal fluid at pH 7.5 according to USP 24 and in a pH 7.0 solution designed to mimic the ionic conditions of the small intestine. Results from the intercalation process show that hydrotalcite is able to intercalate diclofenac with a simple procedure and with a good drug loading (55% wt/wt). The in vitro drug release was remarkably lower than that from the corresponding physical mixture at both pH 7.5 and pH 7.0. In the latter case, the release was not complete at 24 hours. The kinetic analysis shows the importance of the diffusion through the particle in controlling the drug release rate. The obtained results show that hydrotalcite may be used to prepare modified release formulations.

Capreomycin inhalable powders prepared with an innovative spray-drying technique.

The aim of the work was to produce inhalable capreomycin powders using a novel spray-drying technology. A 2(3) factorial design was used to individuate the best working conditions. The maximum desirability was identified at the smallest mean volume diameter (dv) and span, and the highest yield. Powders were characterized for size, morphology, flowability and aerodynamic properties. Mathematical models showed a good predictivity with biases lower than 20%. The maximum conformity with desirability criteria was obtained spraying a 10mg/mL bacitracin solution at 111 °C with the 4 μm pore size membrane. By processing capreomycin sulfate with the parameters optimized for bacitracin, an inhalable powder was obtained (i.e., yield of 82%, dv of 3.83 μm, and span of 1.04). By further optimization, capreomycin sulfate powder characteristics were improved (i.e., yield, ∼71%; dv, 3.25 μm; span, 0.95). After formulation with lactose, emitted dose and respirable fraction of 87% and ∼27% were obtained, respectively. Two capreomycin sulfate powders with suitable properties for inhalation were produced using the nano spray-dryer B-90.

Oxybenzone Entrapped in Mesoporous Silicate MCM-41

AbstractPurposeOxybenzone is an organic ultraviolet absorbent commonly used as photoprotection agent in cosmetic formulations. Unfortunately, it shows safety problems because of its potential systemic absorption and skin photosensibilization. Thus, a new particulate carrier is proposed with the aim of solving these problems.MethodsOxybenzone (OXY) was loaded into the mesopores of the silicate MCM-41 and the obtained particulate carrier (MCM-41-OXY) was mixed with melt tristearin or stearyl alcohol with the aim of plugging the MCM-41 mesopores and thus entrapped OXY inside the pores. These particles were characterized and incorporated in an emulgel. OXY release from these formulations was evaluated in vitro and was compared with those from emulgels containing free OXY and unplugged MCM-41-OXY. The photoprotection range of the hybrid materials was also investigated through spectrophotometric measurements.ResultsAs concerns with UV absorption properties, it can be observed that the spectrum of the neat compound appears broader than those recorded for lipid/silicate particles and MCM-41-OXY, but MCM-41-OXY with tristearin presents a higher absorption intensity in UVA, UVB, and UVC regions, maintaining thus excellent photoprotection effects. Besides this aspect, the pore occlusion by means of the lipid ingredients offers a proper obstacle to sunscreen release, thus preventing the contact between the sunscreen and the skin and consequently both systemic absorption and cutaneous adverse reactions.ConclusionsThe new lipid/MCM-41 particles appear to be promising candidates to formulate sunscreen preparations. FigureAbsorption spectra of neat OXY (black line) (a), MCM-41-OXY (red line) (b), MCM-41-OXYSTE (blue line) (c) and MCM-41-OXY- TRI (green line) (d) (on the left) and in vitro release profiles of OXY from neat OXY (a) and MCM-41-OXY (b) emulgels (on the right).

Nanostructured hybrids for the improvement of folic acid biopharmaceutical properties

Folic acid (FA) is an important source for the prevention of many diseases. However, its use is limited because the very low solubility (<10 mg/l particularly in the gastric environment) responsible for the incomplete adsorption of the administered dose. This study proposes a technological strategy to overcome this problem enhancing FA dissolution rate by means of a formulation able to make completely bioavailable the whole administered dose.