In vitro release testing of matrices based on starch–methyl methacrylate copolymers: Effect of tablet crushing force, dissolution medium pH and stirring rate

Alleviating the Influence of Circadian Rhythms and Drug Properties to the Release of Paliperidone Gel Matrix Tablets with Compression Coating Technology and Microenvironment Shaping

The influence of circadian rhythms is an important content in oral dosage form study which is shown as different pH conditions and gastrointestinal dynamics in the gastrointestinal tract. The purpose of this study was to alleviate the influence of circadian rhythms and drug properties to the release of gel matrix tablets in vitro and in vivo. In this study, the compression coating technology and microenvironment shaping were utilized to achieve the alleviation of the influence of circadian rhythms and drug properties. The compression coating technology was used to alleviate the influence of gastrointestinal dynamics, and microenvironment shaping was used to alleviate the interference of different pH condition variations. The self-made compression coating tablet could maintain a consistent release rate in different pH conditions and different dynamic environments in vitro for 24 h. In vivo, the pharmacokinetic parameters C_max and T_max were 3701.675 ng/mL and 24 h, respectively, and the release effect in vivo was similar to the paliperidone osmotic pump tablet with the ability to alleviate the influence of circadian rhythms. The correlation coefficient R² was 0.9914 for the self-made paliperidone compression coating tablet in vitro-in vivo correlation. The interference caused by circadian rhythms was alleviated so that the compression coating technology with microenvironment shaping could replace the osmotic pump technology with easier preparation process and cheaper costs in vitro and in vivo and achieve the effect of alleviating the interference of circadian rhythms.

Fabrication and antibacterial evaluation of peppermint oil-loaded composite microcapsules by chitosan-decorated silica nanoparticles stabilized Pickering emulsion templating

Novel peppermint oil (PO)-loaded composite microcapsules (CM) with hydroxypropyl methyl cellulose (HPMC)/chitosan/silica shells were effectively fabricated by PO Pickering emulsion, which were stabilized with chitosan-decorated silica nanoparticles (CSN). The surface modification of chitosan could improve the hydrophobicity of silica nanoparticles and favor their adsorption at the oil-water interface of PO Pickering emulsions. The microcapsule composite shells were formed dependent on the electrostatic adsorption of HPMC and CSN, and further subjected to spray-drying. The peppermint oil-loaded composite microcapsules with 100% HPMC as wall material (PO-CM@100%HPMC) seemed to be optimum formulation based on the prolonged release, acceptable entrapment efficiency (89.1%) and drug loading (25.5%). The PO-CM@100%HPMC could remarkably prolong the stability of PO. Moreover, the PO-CM@100%HPMC had a long-term antimicrobial activity (85.4%) against S. aureus and E. coli even after storage for 60 days. Therefore, the Pickering emulsions based microcapsules seemed to be a promising strategy for antibacterial application for PO.

Interactions between mesocellular foam silica carriers and model drugs constructed by central composite design

In this work, the influences of the four factors including hydrogen bond acceptor (HBA) count (X₁), MCF pore size (X₂), drug loading degree (X₃) and dissolution stirring rate (X₄) as well as their cross-interactions for drug release behaviors were investigated. The factors were chosen from all drug release aspects consisting of drug, carrier, formulation and dissolution, respectively. A five-level four-factorial composite central design (CCD) was performed for the investigation with cumulative release over 1 h (Y₁), cumulative release over 24 h (Y₂) and rate constant k (Y₃) as three dependent response variables. A series of MCFs (4MCF, 7MCF, 12MCF, 17MCF and 22MCF) with various pore diameters were synthesized to be applied as drug carriers, and five BCS II drugs including disulfiram (DIS), loratadine (LOR), celecoxib (CEL), metronidazole (MET) and nimodipine (NIM) were selected as model drugs possessing different numbers of HBAs. The morphologies, structures and pore size distributions of the MCFs were systematically studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption analysis (BET), and the drug loading samples were analyzed using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The release behavior was examined by in vitro dissolution. The interactions between the model drugs and the MCFs were analyzed in detail using response surface plots. The present work may provide some scientific references for selecting the appropriate mesoporous silica carrier for a specific drug.

Application of a Biodegradable Polyesteramide Derived from L-Alanine as Novel Excipient for Controlled Release Matrix Tablets

This pre-formulation study assays the capacity of the polyesteramide PADAS, poly (L-alanine-dodecanediol-L-alanine-sebacic), as an insoluble tablet excipient matrix for prolonged drug release. The flow properties of PADAS were suitable for tableting, and the compressibility of tablets containing exclusively PADAS was evaluated by ESEM observation of the microstructure. The tablets were resistant to crushing and non-friable and they did not undergo disintegration (typical features of an inert matrix). Tablets containing 33.33% sodium diclofenac (DF), ketoprofen (K) or dexketoprofen trometamol (DK-T) as a model drug, in addition with 66.67% of polymer, were formulated, and the absence of interactions between the components was confirmed by differential scanning calorimetry. Dissolution tests showed that PADAS retained DF and K and prolonged drug release, following a Higuchi kinetic. The tablets containing DK-T did not retain the drug sufficiently for prolonged release to be established. Tablets containing DK-T and 66.67, 83.33 or 91.67% PADAS, compressed at 44.48 or 88.96 kN, were elaborated to determine the influence of the polymer amount and of the compression force on DK-T release. Both parameters significantly delayed drug release, except when the proportion of polymer was 91.67%.

Invivo absorption behaviour of theophylline from starch-methyl methacrylate matrix tablets in beagle dogs

This study evaluates in vivo the drug absorption profiles from potato starch-methyl methacrylate matrices(*) using theophylline as a model drug. Healthy beagle dogs under fasting conditions were used for in vivo studies and plasma samples were analyzed by a fluorescence polarization immunoassay analysis (FPIA method). Non-compartmental and compartmental (population approach) analysis was performed to determine the pharmacokinetic parameters. The principle of superposition was applied to predict multiple dose plasma concentrations from experimental single dose data. An in vitro-in vivo correlation (IVIVC) was also assessed. The sustained absorption kinetics of theophylline from these formulations was demonstrated by comparison with two commercially available oral sustained-release theophylline products (Theo-Dur(®) and Theolair(®)). A one-compartment model with first order kinetics without lag-time best describes the absorption/disposition of theophylline from the formulations. Results revealed a theophylline absorption rate in the order FD-HSMMA≥Theo-Dur(®)≥OD-CSMMA>Theolair(®)≥FD-CSMMA. On the basis of simulated plasma theophylline levels, a twice daily dosage (every 12h) with the FD-CSMMA tablets should be recommended. A Level C IVIVC was found between the in vitrot50% and the in vivo AUC/D, although further optimization of the in vitro dissolution test would be needed to adequately correlate with in vivo data.

Gastro-floating bilayer tablets for the sustained release of metformin and immediate release of pioglitazone: preparation and in vitro/in vivo evaluation

Owing to the complementary mechanisms of action of metformin hydrochloride (MH) and pioglitazone hydrochloride (PG), combination therapy for type 2 diabetes mellitus using the two drugs is highly desired; on the other hand, MH is not well absorbed in lower gastrointestinal tract and has a short half-life, therefore compromising the therapeutic effects. Herein, the present study was to develop gastro-floating bilayer matrix tablets in which the two drugs were incorporated into two separate layers, aiming at sustaining MH release with enhanced absorption and achieving immediate release of PG. The tablets of the optimized formulation floated on the test medium for more than 24 h with 5 min of floating lag time, and sustained MH release for 12 h via a diffusion-dependent manner; and complete release of PG within 5 min were achieved. Moreover, a steady plasma concentration of MH with a 1.5-fold increase in bioavailability, decreased C(max) and reduced T(max) was obtained, and the in vivo behavior of PG was similar to the marked product. Summarily, sustained MH release with improved absorption and immediate release of PG were obtained simultaneously using the gastro-floating bilayer tablet, allowing strengthened combination therapy for diabetes mellitus.