Comparative evaluation of drug release from aged prolonged polyethylene oxide tablet matrices: effect of excipient and drug type

Development of a Model Based on Physical Mechanisms for the Explanation of Drug Release: Application to Diclofenac Release from Polyurethane Films

In this study, we present a method for prediction of the drug-release profile based on the physical mechanisms that can intervene in drug release from a drug-carrier. The application presented here incorporates the effects of drug concentration and Reynolds number defining the circulating flow in the testing vein. The experimental data used relate to the release of diclofenac from samples of non-degradable polyurethane subjected to static and continuous flow. This case includes simultaneously three mechanisms: burst-release, diffusion and osmotic pressure, identified beforehand here as being able to contribute to the drug liberation. For this purpose, authors coded the Sequential Quadratic Programming Algorithm to solve the problem of non-linear optimization. The experimental data used to develop the mathematical model obtained from release studies carried out in water solution at 37 °C, for three concentrations of diclofenac and two water flow rates. We discuss the contribution of mechanisms and kinetics by considering two aforementioned parameters and, following that, we obtain the specific-model and compare the calculated results with the experimental results for the reserved cases. The results showed that drug percentage mostly affect the burst release, however flow rate has affected the osmotic release. In addition, release kinetics of all the mechanisms have increased by increasing the values of two considered parameters.

Polyethylene oxide and its controlled release properties in hydrophilic matrix tablets for oral administration

Polymers are excipients that modify the rate of drug release from pharmaceutical dosage forms. Hydrophilic polymer-based controlled drug delivery system is more advantageous as compared to the conventional delivery system as it reduces the dosing frequency, improves therapeutic efficacy, reduces side-effects, and probably enhances patient compliance. Polyethylene oxide (PEO), a nonionic hydrophilic polymer, is one of the most widely used polymers for extending the drug release. This review mainly focuses on the PEO marketed by, but not limited to, The Dow Chemical Company under the trade name of POLYOX^TM. It is commercially available polyethylene oxide polymer existing in various molecular weight and viscosity grades depending upon the application. This study essentially discusses chemistry, physicochemical properties, and the impact of formulation and processing variables on the release of drug from hydrophilic PEO matrix tablets. Moreover, it also summarizes the stability, patents, and regulatory perspectives of POLYOX that can further influence the future developments of controlled release dosage forms.

Multi-dimensional visualization for the morphology of lubricant stearic acid particles and their distribution in tablets

The shapes of particles and their distribution in tablets, controlled by pretreatment and tableting process, determine the pharmaceutical performance of excipient like lubricant. This study aims to provide deeper insights to the relationship of the morphology and spatial distribution of stearic acid (SA) with the lubrication efficiency, as well as the resulting tablet property. Unmodified SA particles as flat sheet-like particles were firstly reprocessed by emulsification in hot water to obtain the reprocessed SA particles with spherical morphology. The three-dimensional (3D) information of SA particles in tablets was detected by a quantitative and non-invasive 3D structure elucidation technique, namely, synchrotron radiation X-ray micro-computed tomography (SR-µCT). SA particles in glipizide tablets prepared by using unmodified SA (GUT), reprocessed SA (GRT), as well as reference listed drug (RLD) of glipizide tablets were analyzed by SR-µCT. The results showed that the reprocessed SA with better flowability contributed to similarity of breaking forces between that of GRT and RLD. SA particles in GRT were very similar to those in RLD with uniform morphology and particle size, while SA particles in GUT were not evenly distributed. These findings not only demonstrated the feasibility of SR-µCT as a new method in revealing the morphology and spatial distribution of excipient in drug delivery system, but also deepened insights of solid dosage form design into a new scale by powder engineering.

Gastric floating sustained-release tablet for dihydromyricetin: Development, characterization, and pharmacokinetics study

Dihydromyricetin (DHM) is a natural dihydroflavonol compound with quite a number of important pharmacological properties. However, its low solubility in water and poor stability in aqueous environment, have compromised drug efficacy of DHM, thus hindering its clinical use. The present study was to develop DHM-loaded gastric floating sustained-release tablet (DHM-GFT) to improve the bioavailability of DHM. DHM-GFT was prepared via powder direct compression. The formulation of tablet was optimized in terms of the floating ability and drug release rate. The optimized DHM-GFT exhibited short floating lag time of less than 10 s and long floating duration of over 12 h in acidic medium. It had a 12-hour sustained release of DHM, which proved its potential to develop as a twice-a-day dosing preparation. The physicochemical properties of DHM-GFT well satisfied the pharmacopoeial requirements. In addition, the results from pharmacokinetic studies demonstrated that, DHM-GFT could considerably prolong the in vivo residence time of drug and improve the bioavailability via good gastric floating ability and sustained drug release when compared to DHM powder. Therefore, DHM-GFT is promising to promote the application of DHM and merits studies for further development.

Stability and bioavailability of diltiazem/polyethylene oxide matrix tablets

The aim of this study was to prepare and evaluate in vitro and in vivo; Diltiazem-Hydrochloride (DTZ) in sustained-release matrix tablets. Stability of DTZ tablets prepared with polyethylene oxide (MWs 900 000, 4 000 000, and 8 000 000) with or without addition of electrolytes was carried-out for 1-month, under short-term storage at 40 °C/75% RH. Stability was evaluated by DTZ content, DSC and drug release using the Flow-Through Cell (USP # IV). The majority of stored tablets were stable for 1-month under short-term storage with respect to DTZ content and drug release. DSC curves of stored samples showed appearance of new exothermic peak after 1-month storage at 40 °C/75% RH, which was not observed after 5 years storage at room temperature. A selected formula was tested in vivo against reference product on eight healthy human volunteers. DTZ-plasma profiles were different between the two formulae. However, no statistically significant differences were detected between C_max, AUC_0-48 and AUC_0-∞. The two products were therapeutically in-equivalent, as 90% confidence intervals "T/R" were 88.82-205.76, 91.40-139.94, and 93.73-134.97 for C_max, AUC_0-48 and AUC_0-∞, respectively. This study highlighted possible differences observed between the two regimes frequently applied for stability testing.