Study of controlled-release floating tablets of dipyridamole using the dry-coated method

Design and Evaluation of Ginkgolides Gastric Floating Controlled Release Tablets Based on Solid Supersaturated Self-nanoemulsifying

Ginkgolides are receptor antagonist of platelet activating factor with great clinical prospect, but its application is limited by its low solubility, short half-life and poor alkaline environment stability. It is difficult to solve these problems with a single drug delivery system. In this study, supersaturated self-nanoemulsifying gastric floating tablets of ginkgolides were developed through the combination of solid supersaturated self-nanoemulsifying drug delivery system (solid S-SNEDDS) and gastric retentive floating drug delivery system (GFDDS) to solve these problems of ginkgolides. Solid S-SNEDDS was prepared by D-optimal mixture design, normalization method and single factor experiment. The properties of solid-S-SNEDDS were studied by TEM, PXRD, FT-IR, SEM and in vitro drug release profile. Then, the optimal formulation of stomach floating tablet was obtained through single factor experiment and center composite design, followed by the study of in vitro release, model and mechanism of release, in vitro buoyancy and kinetics of erosion and swelling. PXRD and FT-IR showed that the drug in solid S-SNEDDS existed in an amorphous manner and formed hydrogen bond with excipients. The results showed that the cumulative release of GA and GB in the optimal tablets was 96.12% and 92.57% higher than the simple tablets within 12 h. The release mechanism of the tablet was skeleton erosion and drug diffusion. In 12 h, the optimal tablets can float stably in vitro and release the drug at a constant rate, with a cumulative release of more than 80%. In summary, the combination of SNEDDS and GFDDS is a promising means to solve the problems of ginkgolides.

Optimized copolymeric microstructured platforms for smart controlled delivery of an anticoagulant drug: Preparation, in vitro assessment and crossover study in healthy adult human volunteers

In the present study, novel micro-structured copolymeric carriers were developed based on the grafting technology where acrylamide was chemically crosslinked with different types of Eudragits® (NE30D, L100, RL30D, or RS30D) based on a 4¹*2¹ factorial design. The designed systems efficiently engulfed the anticoagulant drug dipyridamole (DIP), within their formed entangled mesh of crosslinked polymeric network. An optimized formulation, ECOP4 with a desirability-value of 0.706, (in which DIP is engulfed within a copolymeric network of acrylamide and Eudragit® RS30D) showed high engulfment capacity (97.13 ± 1.34%) and controlled DIP release over 8 h. FTIR studies revealed absence of interactions between DIP and the formed copolymer. ECOP4 was further inserted within an easily-administered safe raft forming system composed of a mixture of LM-pectin and gellan gum. A pharmacokinetic study was performed using human volunteers to determine DIP concentration in their plasma after administering the designed formulation using the high-performance liquid chromatography (HPLC) method. A crossover design was adopted comparing the designed formulation with Persantin® 25 mg tablets as a reference standard. Superior results were obtained for the optimized formulation regarding the measured pharmacokinetic parameters (AUC_0-24h, C_max, and T_max) with a 2.31 fold increase in relative bioavailability, which reveals the usefulness of the designed grafted dipyridamole formulation in site-specific delivery system.

Gastroretentive Technologies in Tandem with Controlled-Release Strategies: A Potent Answer to Oral Drug Bioavailability and Patient Compliance Implications

There have been many efforts to improve oral drug bioavailability and therapeutic efficacy and patient compliance. A variety of controlled-release oral delivery systems have been developed to meet these needs. Gastroretentive drug delivery technologies have the potential to achieve retention of the dosage form in the upper gastrointestinal tract (GIT) that can be sufficient to ensure complete solubilisation of the drugs in the stomach fluids, followed by subsequent absorption in the stomach or proximal small intestine. This can be beneficial for drugs that have an “absorption window” or are absorbed to a different extent in various segments of the GIT. Therefore, gastroretentive technologies in tandem with controlled-release strategies could enhance both the therapeutic efficacy of many drugs and improve patient compliance through a reduction in dosing frequency. The paper reviews different gastroretentive drug delivery technologies and controlled-release strategies that can be combined and summarises examples of formulations currently in clinical development and commercially available gastroretentive controlled-release products. The different parameters that need to be considered and monitored during formulation development for these pharmaceutical applications are highlighted.

Relevancy of Nizatidine’s Release from Floating Tablets with Viscosity of Various Cellulose Ethers

Nizatidine is a gastroprotective drug with a short biological half-life and narrow absorption window. This study aimed at developing floating tablets of nizatidine using various HPMC viscosity grades, namely K4M, E4M, K15 and K200M. Directly compressed tablets revealed an excellent uniformity in hardness, thickness and weight and nizatidine was evenly distributed within the matrix floating tablets. Buoyancy study revealed floating lag time as low as 18–38 s, and tablets remain buoyant for upto 24 h. However, the later depended upon viscosity grade of HPMC and that the higher the viscosity, the less was the total floating time. In vitro dissolution indicated viscosity dependent nizatidine release from the floating tablets. HPMC K4M and E4M based floating tablets released almost 100% drug in 12 h, whilst higher viscosity polymers such as K15 and K200M only released 81.88% and 75.81% drug, respectively. The drug release followed non-Fickian diffusion from tablets formulated with K4M, K15 and K200M, whilst super case II transport was observed with E4M based tablets. More interestingly, K4M and E4M polymers have similar viscosity yet exhibited different drug release mechanism. This was attributed to the difference in degree of substitution of methoxyl- and hydroxypropoxyl- groups on polymer backbone.

Three-Dimensional (3D)-Printed Zero-Order Released Platform: a Novel Method of Personalized Dosage Form Design and Manufacturing

In 2017, there are 451 million people with diabetes worldwide. These figures were expected to increase to 693 million by 2045. The research and development of hypoglycemic drugs has become a top priority. Among them, sulfonylurea hypoglycemic drugs such as glipizide are commonly used in non-insulin-dependent type II diabetes. In order to adapt to the wide range of hypoglycemic drugs and the different individual needs of patients, this topic used glipizide as a model drug, and prepared glipizide preparations with 3D printing technology. The purpose of this study was to investigate the prescription applicability and control-release behavior of structure and explore the application prospects of 3D printing personalized drug delivery formulations. This article aims to establish a production process for personalized preparations based on 3D printing technology. The process is easy to obtain excipients, universal prescriptions, flexible dosages, exclusive customization, and integrated automation. In this paper, the UV method was used to determine the in vitro release and content analysis method of glipizide; the physical and chemical properties of the glipizide were investigated. The established analysis method was inspected and evaluated, and the experimental results met the methodological requirements. Glipizide controlled-release tablets were prepared by the semisolid extrusion (SSE) method using traditional pharmaceutical excipients combined with 3D printing technology. The formulation composition, in vitro release, and printing process parameters of the preparation were investigated, and the final prescription and process parameters (traveling speed 6.0-7.7 mm/s and extruding speed 0.0060-0.0077 mm/s) were selected through comprehensive analysis. The routine analysis results of the preparation showed that the performance of the preparation meets the requirements. In order for 3D printing technology to play a better role in community medicine and telemedicine, this article further explored the universality of the above prescription and determined the scope of application of prescription drugs and dosages. Glipizide, gliclazide, lornoxicam, puerarin, and theophylline were used as model drugs, and the range of drug loading percentage was investigated. The results showed when the solubility of the drug is 9.45 -8.34 mg/mL, and the drug loading is 3-43%; the release behavior is similar.

Novel self-floating tablet for enhanced oral bioavailability of metformin based on cellulose

Metformin has several problems such as low bioavailability, short half-life, and narrow absorption window, sustained and site-specific drug delivery system is required. Floating drug delivery systems are very useful to achieve these purposes. However, conventional floating systems have several limitations; lag time, a high proportion of excipient in the tablet, using non-biocompatible excipient, and requirement of a complicated procedure. To overcome these obstacles, we developed a hollow-core floating tablet (HCFT). The HCFT immediately floated in pH 1.2, 4.0, 6.8 medium, and even distilled water. The floating duration time of HCFT was>24 h. From the in vitro release study, it was confirmed that HCFT showed the sustain release profile of metformin for 12 h. Water uptake and matrix erosion were evaluated for predicting the buoyancy and drug release kinetics of HCFT in the body. Factor analysis was applied to optimize the formulation. There were significant (p < 0.05) differences in metformin plasma concentration of 4 h and 6 h between two groups. Compared with Glucophage® XR, the relative bioavailability of metformin HCFT was 123.81 ± 3.52%. The X-ray imaging of optimized formulation revealed that HCFT was constantly floating in the stomach region of the rabbit, thereby indicating improved gastric retention for>6 h. Consequently, all the findings indicate that HCFT could be an effective gastric retention system and applied extensively to other drugs with narrow absorption windows.

Development and Evaluation of Compression Coating Gastro-Floating Tablet of Alfuzosin Hydrochloride for Zero-Order Controlled Release

Alfuzosin hydrochloride is an appropriate candidate drug to prepare a gastro-retention controlled release dosage form since it demonstrates a narrow absorption window in the proximal section of the gastrointestinal tract with a short half-life. The purpose of the present study was to develop and optimize a gastro-floating tablet of alfuzosin hydrochloride by using the compression coating method for controlling drug release in a controlled manner. The floating tablets were developed utilizing hydroxypropyl methylcellulose and carbomer as matrix materials. The impact of formulation factors on buoyancy property and in vitro drug release of the floating tablet was investigated. The "similarity factor" (f₂) was used as the indicator for the optimization of the formulations. Furthermore, in vivo pharmacokinetic study in rabbits and correlation of in vitro/in vivo study were also performed. It was found that the optimized formulation F9 could float immediately less than 2 min and remain lastingly buoyant over 24 h and follow zero-order release kinetics well. In comparison with the commercially available prolonged release tablets XATRAL® XL, the prepared floating tablet exhibited similar pharmacokinetic parameters (C_max, T_max, t_1/2, and AUC_0 - t) and plasma concentration versus time profile. Moreover, it indicated from the correlation of in vitro/in vivo study that the floating tablets exhibited a good correlation of in vitro/in vivo. In summary, the compression coating gastro-floating tablets might be a promising drug delivery system for alfuzosin hydrochloride to control drug release.