Denatured Whey Protein Powder as a New Matrix Excipient: Design and Evaluation of Mucoadhesive Tablets for Sustained Drug Release Applications

Recent developments in natural biopolymer based drug delivery systems

Targeted delivery of drug molecules to diseased sites is a great challenge in pharmaceutical and biomedical sciences. Fabrication of drug delivery systems (DDS) to target and/or diagnose sick cells is an effective means to achieve good therapeutic results along with a minimal toxicological impact on healthy cells. Biopolymers are becoming an important class of materials owing to their biodegradability, good compatibility, non-toxicity, non-immunogenicity, and long blood circulation time and high drug loading ratio for both macros as well as micro-sized drug molecules. This review summarizes the recent trends in biopolymer-based DDS, forecasting their broad future clinical applications. Cellulose chitosan, starch, silk fibroins, collagen, albumin, gelatin, alginate, agar, proteins and peptides have shown potential applications in DDS. A range of synthetic techniques have been reported to design the DDS and are discussed in the current study which is being successfully employed in ocular, dental, transdermal and intranasal delivery systems. Different formulations of DDS are also overviewed in this review article along with synthesis techniques employed for designing the DDS. The possibility of these biopolymer applications points to a new route for creating unique DDS with enhanced therapeutic qualities for scaling up creative formulations up to the clinical level.

Evaluating the Effect of Microcrystalline Cellulose Variations on Tablet Quality of Natural Plant Product Using a Design of Experiment Approach

Microcrystalline cellulose (MCC) of different grades from different manufacturers differ in particulate and powder properties significantly. The choice of MCC is important to the development of a tablet formulation with satisfactory quality. In this study, the effects of five different MCCs (KG 802, Pharmacel 102, MC 302, M 200, and PH 112) that had different compactibility and tablet disintegration on the tablet quality of two different natural plant products (NPPs) were evaluated systematically, including Crataegi Folium ethanol extract (CF-E) and Sarcandrae Herba water extract (SH-W). The result of D-optimal mixture designs demonstrated that KG 802 showed the best ability to improve compression properties and tensile strength, followed by Pharmacel 102, MC 302, and M 200. PH 112 did the weakest. However, MCCs of different grades had no different influence on the disintegration of NPP tablets. Similar results were found in the experiments of the two different NPP powders, suggesting the generalization of the finding. Moreover, KG 802-containing CF-E formulations showed the largest optimum region size, that is, the lowest production risk. The design space sizes of SH-W were hardly sensitive to the change of MCCs, due to the better tabletability. In conclusion, the properties of MCCs could transfer to the high NPP loading (70%) formulations, leading to the variations on the compression properties and tablet quality. The poorer the tabletability of NPP, the more obvious the variation. The result is promising for the use of MCC and the manufacturing of high drug-loading NPP tablets by direct compression.

An update on microcrystalline cellulose in direct compression: Functionality, critical material attributes, and co-processed excipients

Microcrystalline cellulose (MCC) is one of the most popular cellulose derivatives in the pharmaceutical industry. Thanks to its outstanding tabletability, MCC is generally included in direct compression (DC) tablet formulations containing poor-tabletability active pharmaceutical ingredients. Nowadays, numerous grades of MCC from various brands are accessible for pharmaceutical manufacturers, leading to variability in MCC properties. Hence, it seems to be worthy and urgent to evaluate the influences of MCC variability on tablet quality and to identify critical material attributes (CMAs) based on the idea of Quality by Control. Besides, MCC-based co-processed excipients can effectively combine the functions of the filler, binder, disintegrant, lubricant, glidant, or flavor, and thus have drawn extensive interest. In this review, we focused specifically on the recent advances and development of MCC on DC tableting, including the functions in tablet formulations, potential CMAs, and MCC-based co-possessed excipients, therefore providing a reference for further studies.

Robustness of Controlled Release Tablets Based on a Cross-linked Pregelatinized Potato Starch Matrix

The aim of this study was to evaluate the potential of a cross-linked pregelatinized potato starch (PREGEFLO® PI10) as matrix former for controlled release tablets. Different types of tablets loaded with diprophylline, diltiazem HCl or theophylline were prepared by direct compression of binary drug/polymer blends. The drug content was varied from 20 to 50%. Two hydroxypropyl methylcellulose grades (HPMC K100LV and K100M) were studied as alternative matrix formers. Drug release was measured in a variety of release media using different types of experimental set-ups. This includes 0.1 N HCl, phosphate buffer pH 6.8 and water, optionally containing different amounts of NaCl, sucrose, ethanol or pancreatin, fasted state simulated gastric fluid, fed state simulated gastric fluid, fasted state simulated intestinal fluid, fed state simulated intestinal fluid as well as media simulating the conditions in the colon of healthy subjects and patients suffering from Crohn's disease. The USP apparatuses I/II/III were used under a range of operating conditions and optionally coupled with the simulation of additional mechanical stress. Importantly, the drug release kinetics was not substantially affected by the investigated environmental conditions from tablets based on the cross-linked pregelatinized potato starch, similar to HPMC tablets. However, in contrast to the latter, the starch-based tablets roughly kept their shape upon exposure to the release media (they "only" increased in size) during the observation period, and the water penetration into the systems was much less pronounced. Thus, the investigated cross-linked pregelatinized potato starch offers an interesting potential as matrix former in controlled release tablets.

Lignin and Cellulose Blends as Pharmaceutical Excipient for Tablet Manufacturing via Direct Compression

Extensive efforts are being made to find alternative uses for lignin (LIG). In the present work the use of this biopolymer as excipient to prepare tablets was studied. For this purpose, LIG was combined with microcrystalline cellulose (MCC) and used as excipients to prepare directly compressed tablets containing a model drug, tetracycline (TC). The excipients contained different concentrations of LIG: 100%, 75%, 50%, 25% and 0% (w/w). Two different compression forces were used (two and five tonnes). When formulations were prepared using LIG as the only excipient, tablets were formed, but they showed lower densities and crushing strength than the ones obtained with only MCC or LIG/MCC blends. Moreover, tablets prepared using five tonnes of compression force showed TC releases ranging from 40% to 70% of the drug loading. On the other hand, the tablets prepared using two tonnes of compression force showed a faster and more efficient TC release, between 60% and 90%. The presence of LIG in the tablets modified significantly the release profile and the maximum amount of TC released. Finally, a DPPH (2,2-diphenyl-1-picrylhydrozyl) assay was performed to confirm that the presence of LIG provided antioxidant properties to the formulations. Accordingly, LIG has potential as a pharmaceutical excipient.

Soy Protein Microparticles for Enhanced Oral Ibuprofen Delivery: Preparation, Characterization, and In Vitro Release Evaluation

The objective of this work was to evaluate soy protein isolate (SPI) and acylated soy protein (SPA) as spray-drying encapsulation carriers for oral pharmaceutical applications. SPI acylation was performed by the Schotten-Baumann reaction. SPA, with an acylation rate of 41%, displayed a decrease in solubility in acidic conditions, whereas its solubility was unaffected by basic conditions. The drug encapsulation capacities of both SPI and SPA were tested with ibuprofen (IBU) as a model poorly soluble drug. IBU-SPI and IBU-SPA particles were obtained by spray-drying under eco-friendly conditions. Yields of 70 to 87% and microencapsulation efficiencies exceeding 80% were attained for an IBU content of 20 to 40% w/w, confirming the excellent microencapsulation properties of SPI and the suitability of the chemical modification. The in vitro release kinetics of IBU were studied in simulated gastrointestinal conditions (pH 1.2 and pH 6.8, 37°C). pH-sensitive release patterns were observed, with an optimized low rate of release in simulated gastric fluid for SPA formulations, and a rapid and complete release in simulated intestinal fluid for both formulations, due to the optimal pattern of pH-dependent solubility for SPA and the molecular dispersion of IBU in soy protein. These results demonstrate that SPI and SPA are relevant for the development of pH-sensitive drug delivery systems for the oral route.

Atomization of denatured whey proteins as a novel and simple way to improve oral drug delivery system properties

In the sphere of drug delivery, denatured whey protein (DWP) has in recent times gained press. However, to date, no scalable and affordable dosage form has been developed. The objective of our study was to evaluate the potential use of spray-dried DWP as a ready to use excipient for oral drug delivery. Therefore, solid state, FTIR spectra and wettability were studied. Dissolution, mucoadhesion and the effect on paracellular permeability were also evaluated. The spray-dried DWP particles were spherical with 4μm mean diameter. Further, relative to native WP, the spray-dried DWP particles bore reduced wettability, and their structure was characterized by the exposure of a high amount of free thiol and by the formation of intermolecular β-sheets. The DWP powders were mucoadhesive, enzymatic inhibitors, biocompatible and they induced the opening of tight junctions. Our study shows great potential for the use of spray-drying as a technique to modify the dissolution rate of drugs and enhance the oral bioavailability of molecules. That is, the use of spray drying as a single step ready to use DWP excipient.