Ibuprofen-loaded ethylcellulose microspheres: release studies and analysis of the matrix structure through the Higuchi model

Preparation, Characterization, and In Vitro Evaluation of Resveratrol-Loaded Cellulose Aerogel

Resveratrol is a natural active ingredient found in plants, which is a polyphenolic compound and has a variety of pharmaceutical uses. Resveratrol-loaded TEMPO-oxidized cellulose aerogel (RLTA) was prepared using a freeze-drying method, employing high speed homogenization followed by rapid freezing with liquid nitrogen. RLTAs were designed at varying drug-cellulose aerogel ratios (1:2, 2:3, 3:2, and 2:1). It could be seen via scanning electron microscopy (SEM) that Res integrated into TEMPO-oxidized cellulose (TC) at different ratios, which changed its aggregation state and turned it into a short rod-like structure. Fourier transform infrared (FTIR) spectra confirmed that the RLTAs had the characteristic peaks of TC and Res. In addition, X-ray diffraction (XRD) demonstrated that the grain size of RLTA was obviously smaller than that of pure Res. RLTAs also had excellent stability in both simulated gastric fluid and phosphate buffer solution. The drug release rate was initially completed within 5 h under a loading rate of 30.7 wt%. The results of an MTT assay showed the low toxicity and good biocompatibility of the RLTAs. TC aerogel could be a promising drug carrier that may be widely used in designing and preparing novel biomedicine.

Pore blocking: An innovative formulation strategy for the design of alcohol resistant multi-particulate dosage forms

In this work calcium stearate (CaSt) multi-particulates loaded with codeine phosphate (COP) were developed in an attempt to provide extended release (ER) combined with alcohol dose dumping (ADD) resistance. The pellets were prepared via wet/extrusion spheronization and ER characteristics were obtained after fluid bed drying at 30°C. Pore blockers (i.e., xanthan, guar gum and TiO2) were integrated to control the uptake of ethanolic media, the CaSt swelling and consequently, the COP release. While all three pore blockers are insoluble in ethanol, xanthan dissolves, guar gum swells and TiO2 does not interact with water. The incorporation of 10 and 15% TiO2 still provided ER characteristics and yielded ADD resistance in up to 40v% ethanol. The in-vitro data were subjected to PK simulations, which revealed similar codeine plasma levels when the medication is used concomitantly with alcoholic beverages. Taken together the in-vitro and in-silico results demonstrate that the incorporation of appropriate pore blockers presents a promising strategy to provide ADD resistance of multi-particulate systems.

Synchronized and controlled release of metformin hydrochloride/glipizide from elementary osmotic delivery

The combination of metformin hydrochloride (MTF) and glipizide (GLZ) is second-line medication for diabetes mellitus type 2 (DMT2). In the present study, elementary osmotic pump ( EOP) tablet is designed to deliver the combination of MTF and GLZ in a sustained and synchronized manner. By analyzing different variables of the formulation, sodium hydrogen carbonate is introduced as pH modifier to improve the release of GLZ, while ethyl cellulose acts as release retardant to reduce the burst release phase of MTF. A two-factor, three-level face-centered central composite design (FCCD) is applied to investigate the impact of different factors on drug release profile. Compared with conventional tablets, the EOP tablet demonstrates a controlled release behavior with relative bioavailability of 99.2% for MTF and 99.3% for GLZ. Data also shows EOP tablet is able to release MTF and GLZ in a synchronized and sustained manner both in vitro and in vivo.

Protein free microcapsules obtained from plant spores as a model for drug delivery: ibuprofen encapsulation, release and taste masking

Sporopollenin exine capsules (SEC) extracted from Lycopodium clavatum spores were shown to encapsulate ibuprofen as a drug model, with 97 ± 1% efficiency as measured by recovery of the loaded drug and absence of the drug on the SEC surface by scanning electron microscopy (SEM). The encapsulated ibuprofen was shown to be unchanged from its bulk crystalline form by solid state NMR, FTIR and XRD. Essential for drug delivery applications, SEC were shown to be non-toxic to human endothelial cells and free of allergenic protein epitopes by MALDI-TOF-MS and ESI-QqToF-MS. Potential application for targeted release into the intestinal region of the gastrointestinal tract (GIT) was demonstrated by 88 ± 1% of the drug being retained in simulated gastric fluid (SGF) after 45 minutes and 85 ± 2% being released after 5 min in buffer (PBS; pH 7.4). The SEC were shown to provide significant taste masking of encapsulated ibuprofen in a double blind trial with 10 human volunteers.

Surface drug removal from ibuprofen-loaded PLA microspheres

The preparation, characterisation and drug release behaviour of ibuprofen loaded poly(D,L-lactic acid) (PLA) microspheres are described. Depending on the gelatin concentration in the aqueous external solution (1, 0.5, 0.1% w/v), microspheres with three different sizes (2.2, 4.1, 7.5 micrometer) were obtained. The properties of microspheres washed with water (Untreated microspheres) (Un-Ms) were compared to those of the microspheres washed with a sodium carbonate solution in order to remove the surface drug (treated microspheres) (T-Ms). The results indicate that the removal of the surface drug did not induce any change in the size of the microspheres whereas the morphology of the smallest T-Ms appeared to be modified. The release profiles of both Un-Ms and T-Ms resulted in biphasic patterns. The initial burst effect (first release phase) of the T-Ms was lower than that of the Un-Ms. The rate of the second release phase did not change for the microspheres with the biggest size but increased for the smallest microspheres probably owing to the modification of the matrix porosity.