Investigation of Dissolution Behavior HPMC/Eudragit®/Magnesium Aluminometasilicate Oral Matrices Based on NMR Solid-State Spectroscopy and Dynamic Characteristics of Gel Layer

Exploration of Neusilin® US2 as an Acceptable Filler in HPMC Matrix Systems-Comparison of Pharmacopoeial and Dynamic Biorelevant Dissolution Study

Modern pharmaceutical technology still seeks new excipients and investigates the further use in already known ones. An example is magnesium aluminometasilicate Neusilin^® US2 (NEU), a commonly used inert filler with unique properties that are usable in various pharmaceutical fields of interest. We aimed to explore its application in hypromellose matrix systems (HPMC content 10–30%) compared to the traditionally used microcrystalline cellulose (MCC) PH 102. The properties of powder mixtures and directly compressed tablets containing individual fillers NEU or MCC, or their blend with ratios of 1.5:1, 1:1, and 0.5:1 were investigated. Besides the routine pharmaceutical testing, we have enriched the matrices’ evaluation with a biorelevant dynamic dissolution study and advanced statistical analysis. Under the USP apparatus 2 dissolution test, NEU, individually, did not provide advantages compared to MCC. The primary limitations were the burst effect increase followed by faster drug release at the 10–20% HPMC concentrations. However, the biorelevant dynamic dissolution study did not confirm these findings and showed similarities in dissolution profiles. It indicates the limitations of pharmacopoeial methods in matrix tablet development. Surprisingly, the NEU/MCC blend matrices at the same HPMC concentration showed technologically advantageous properties. Besides improved flowability, tablet hardness, and a positive impact on the in vitro drug dissolution profile toward zero-order kinetics, the USP 2 dissolution data of the samples N75M50 and N50M50 showed a similarity to those obtained from the dynamic biorelevant apparatus with multi-compartment structure. This finding demonstrates the more predictable in vivo behaviour of the developed matrix systems in human organisms.

Towards a better understanding of thermally treated polycarbophil matrix tablets for controlled release

Polycarbophil (POL), a polyacrylic acid cross-linked with divinyl glycol, is widely used in semisolid and solid dosage forms. When undergoing a thermal treatment in the range 120–160 °C, POL shows interesting morphological modifications, related to changes in physical properties, such as swelling of the powder granules, or hardening and matrix formation if included in the composition of a tablet. Thermal analysis conducted on POL highlighted a thermal event (Z) that can be correlated both to the shrinking of the powder granules and to the matrix formation in compacted POL powder. Modulated differential scanning calorimetry (MDSC) allowed to distinguish, inside event Z, an irreversible process overlapping with a reversible glass transition, attributable to the volatilization of residual solvents identified, through a complex TGA-FTIR-GC–MS interface, as acetate esters used for the polymer production as very fine powder. A specific interaction between acetates and POL, capable of stabilizing the polymer chains in a given conformation, was highlighted. The molecular rearrangement of the POL chains, following the volatilization of the solvent-stabilizers, is therefore ascribable to a loss of energetic stability of this material, which justifies the shrinking phenomena in the granules of the powder and the matrix formation when POL is compacted.

Release kinetics of hydroxypropyl methylcellulose governing drug release and hydrodynamic changes of matrix tablet

BACKGROUND

Hydrophilic hydroxypropyl methylcellulose (HPMC) matrix tablets are the standard role model of the oral controlled-release formulation. Nevertheless, the HPMC kinetics for the mechanistic understanding of drug release and hydrodynamic behaviors are rarely investigated. This study aims to investigate the release behaviors of both HPMC and paracetamol (model drug) from the hydrophilic matrix tablet.

METHODS

Two different viscosity grades of HPMC were used (Low viscosity: 6 cps, High viscosity: 4,000 cps). Three different ratios of drug/HPMC (H:38.08%, M:22.85%, and L:15.23% (w/w) of HPMC amounts in total weight) matrix tablets were prepared by wet granulation technique. The release profiles of the drug and HPMC in a matrix tablet were quantitatively analyzed by HPLC and 1H-nuclear magnetic resonance (NMR) spectroscopy. The hydrodynamic changes of HPMC were determined by the gravimetric behaviors such as swelling and erosion rates, gel layer thickness, front movement data,and distributive near-infrared (NIR) chemical imaging of HPMC in a matrix tablet during the dissolution process.

RESULTS

High viscosity HPMC tablets showed slower release of HPMC than the release rate of drug, suggesting that drug release preceded polymer release.Different hydration phenomenon was qualitatively identified and corresponded to the release profiles. The release behaviors of HPMC and drug in the tablet could be distinguished with the significant difference with fitted dissolution kinetics model (Low viscosity HPMC 6cps; Korsmeyer-Peppas model, High viscosity HPMC 4000cps; Hopfenberg model, Paracetamol; Weibull model) according to the weight of ingredients and types of HPMC.

CONCLUSION

The determination of HPMC polymer release correlating with drug release, hydrodynamic behavior, and NIR chemical imaging of HPMC can provide new insights into the drug release-modulating mechanism in the hydrophilic matrix system.

Stress-Dependent Particle Interactions of Magnesium Aluminometasilicates as Their Performance Factor in Powder Flow and Compaction Applications

In the pharmaceutical industry, silicates are commonly used excipients with different application possibilities. They are especially utilized as glidants in low concentrations, but they can be used in high concentrations as porous carriers and coating materials in oral solid drug delivery systems. The desirable formulations of such systems must exhibit good powder flow but also good compactibility, which brings opposing requirements on inter-particle interactions. Since magnesium aluminometasilicates (MAS) are known for their interesting flow behavior reported as "negative cohesivity" yet they can be used as binders for tablet compression, the objective of this experimental study was to investigate their particle interactions within a broad range of mechanical stress from several kPa to hundreds of MPa. Magnesium aluminometasilicate (Neusilin^® US2 and Neusilin^® S2)-microcrystalline cellulose (Avicel^® PH102) physical powder mixtures with varying silicate concentrations were prepared and examined during their exposure to different pressures using powder rheology and compaction analysis. The results revealed that MAS particles retain their repulsive character and small contact surface area under normal conditions. If threshold pressure is applied, the destruction of MAS particles and formation of new surfaces leading to particle interactions are observed. The ability of MAS particles to form interactions intensifies with increasing pressure and their amount in a mixture. This "function switching" makes MAS suitable for use as multifunctional excipients since they can act as a glidant or a binder depending on the applied pressure.

A microcrystalline cellulose based drug-composite formulation strategy for developing low dose drug tablets

The uniformity of active pharmaceutical ingredient (API) is a main challenge associated with manufacturing low dose tablets. Here, we present a binder enhanced API-microcrystalline cellulose (BEAM) approach to address this challenge. In the BEAM approach a powder is prepared by spraying a PVP hydro-alcoholic solution, which contains API at an appropriate concentration, onto a powder bed of microcrystalline cellulose (MCC) under high shear. BEAM powders of 5 model APIs, with solubility spanning a range of 5 orders of magnitude, all exhibited excellent flowability, tabletability, and low ejection force. Therefore, all BEAM powders could be directly compressed into tablets with excellent API uniformity and fast disintegration without using any other excipients. Compared to traditional ways to address content uniformity problems, this formulation strategy is much more robust and simpler, making it a potential platform technology for manufacturing tablets of potent APIs.

Hypromellose - A traditional pharmaceutical excipient with modern applications in oral and oromucosal drug delivery

Hydroxypropylmethylcellulose (HPMC), also known as Hypromellose, is a traditional pharmaceutical excipient widely exploited in oral sustained drug release matrix systems. The choice of numerous viscosity grades and molecular weights available from different manufacturers provides a great variability in its physical-chemical properties and is a basis for its broad successful application in pharmaceutical research, development, and manufacturing. The excellent mucoadhesive properties of HPMC predetermine its use in oromucosal delivery systems including mucoadhesive tablets and films. HPMC also possesses desirable properties for formulating amorphous solid dispersions increasing the oral bioavailability of poorly soluble drugs. Printability and electrospinnability of HPMC are promising features for its application in 3D printed drug products and nanofiber-based drug delivery systems. Nanoparticle-based formulations are extensively explored as antigen and protein carriers for the formulation of oral vaccines, and oral delivery of biologicals including insulin, respectively. HPMC, being a traditional pharmaceutical excipient, has an irreplaceable role in the development of new pharmaceutical technologies, and new drug products leading to continuous manufacturing processes, and personalized medicine. This review firstly provides information on the physical-chemical properties of HPMC and a comprehensive overview of its application in traditional oral drug formulations. Secondly, this review focuses on the application of HPMC in modern pharmaceutical technologies including spray drying, hot-melt extrusion, 3D printing, nanoprecipitation and electrospinning leading to the formulation of printlets, nanoparticle-, microparticle-, and nanofiber-based delivery systems for oral and oromucosal application. Hypromellose is an excellent excipient for formulation of classical dosage forms and advanced drug delivery systems. New methods of hypromellose processing include spray draying, hot-melt extrusion, 3D printing, and electrospinning.

Reducing Burst Release Effect of Freely Water-Soluble Drug Incorporated into Gastro-Floating Formulation Below HPMC Threshold Concentration Through Interpolymer Complex

Undesired-burst release effect is observed in a freely water-soluble drug formulated into a gastro-floating formulation with effervescent (GFFE) delivery system. In order to address this limitation, interpolymer complex (IPC) of two swellable and non-soluble polymers, poly-ammonium methacrylate and poly-vinyl acetate, was incorporated into hydroxypropyl methyl cellulose (HPMC)-based matrix GFFE. This research studied the effect and interaction of the IPC-HPMC blending on the drug release of GFFE using a freely water-soluble drug, metformin HCl, under different threshold concentration levels and curing effect. The interaction between the IPC and HPMC was characterized using vibrational spectroscopy and thermal analyses under curing and swelling conditions. Anti-solvent followed by lyophilization had better physicochemical and physicomechanic properties than spray dying technique. The interaction was observed by a specific shifting of the vibrational peaks and alteration of the thermal behavior pattern. These effects altered the drug release behavior. Thereafter, the IPC reduced burst release effects in the initial time and during testing, and the IPC improved the HPMC matrix robustness under mechanical stress testing below threshold concentration of HPMC matrix formulated in the GFFE.

GC-MS Analysis of the Composition of the Extracts and Essential Oil from Myristica fragrans Seeds Using Magnesium Aluminometasilicate as Excipient

Myristica fragrans (f. Myristicaceae) seeds are better known as a spice, but their chemical compounds may have a pharmacological effect. The yield of their composition of extracts and essential oils differs due to different methodologies. The aim of this study was to evaluate an excipient material-magnesium aluminometasilicate-and to determine its influence on the qualitative composition of nutmeg extracts and essential oils. Furthermore, we wanted to compare the yield of essential oil. The extracts were prepared by maceration (M) and ultrasound bath-assisted extraction (UAE), and the essential oil-by hydrodistillation (HD). Conventional methods (UAE, HD) were modified with magnesium aluminometasilicate. The samples were analyzed by gas chromatography-mass spectrometry (GC-MS) method. From 16 to 19 chemical compounds were obtained using UAE with magnesium aluminometasilicate, while only 8 to 13 compounds were obtained using UAE without an excipient. Using our conditions and plant material, for the first time eight new chemical compounds in nutmeg essential oil were identified. Two of these compounds (γ-amorphene and cis-α-bergamotene) were obtained with the use of excipient, the other six (β-copaene, bergamotene, citronellyl decanoate, cubebol, cubenene, orthodene) by conventional hydrodistillation. Magnesium aluminometasilicate significantly increased the quantity of sabinene (from 6.53% to 61.42%) and limonene (from 0% to 5.62%) in essential oil. The yield of the essential oil from nutmeg seeds was significantly higher using magnesium aluminometasilicate; it increased from 5.25 ± 0.04% to 10.43 ± 0.09%.

Highly Soluble Drugs Directly Granulated by Water Dispersions of Insoluble Eudragit® Polymers as a Part of Hypromellose K100M Matrix Systems

The aim of the present study was to investigate the suitability of insoluble Eudragit® water dispersions (NE, NM, RL, and RS) for direct high-shear granulation of very soluble levetiracetam in order to decrease its burst effect from HPMC K100M matrices. The process characteristics, ss-NMR analysis, in vitro dissolution behavior, drug release mechanism and kinetics, texture profile analysis of the gel layer, and PCA analysis were explored. An application of water dispersions directly on levetiracetam was feasible only in a multistep process. All prepared formulations exhibited a 12-hour sustained release profile characterized by a reduced burst effect in a concentration-dependent manner. No effect on swelling extent of HPMC K100M was observed in the presence of Eudragit®. Contrary, higher rigidity of formed gel layer was observed using combination of HPMC and Eudragit®. Not only the type and concentration of Eudragit®, but also the presence of the surfactant in water dispersions played a key role in the dissolution characteristics. The dissolution profile close to zero-order kinetic was achieved from the sample containing levetiracetam directly granulated by the water dispersion of Eudragit® NE (5% of solid polymer per tablet) with a relatively high amount of surfactant nonoxynol 100 (1.5%). The initial burst release of drug was reduced to 8.04% in 30 min (a 64.2% decrease) while the total amount of the released drug was retained (97.02%).

Preparation and in vitro-in vivo evaluation of intestinal retention pellets of Berberine chloride to enhance hypoglycemic and lipid-lowing efficacy

Berberine chloride (BBR) is a pharmacokinetic profile of drug with poor bioavailability but good therapeutic efficacy, which is closely related to the discovery of BBR intestinal target. The major aim of this paper is to develop BBR intestinal retention type sustained-release pellets and evaluate their in vivo and in vitro behaviors base on the aspect of local action on intestinal tract. Here, wet milling technology is used to improve dissolution and dissolution rate of BBR by decreasing the particle size and increasing the wettability. The pellets are prepared by liquid layer deposition technology, and then the core pellets are coated with Eudragit^® L30D-55 and Eudragit^® NE30D aqueous dispersion. The prepared pellets show high drug loading capacity, and the drug loading up to 93%. Meanwhile, it possesses significant sustained drug release effect in purified water which is expected to improve the pharmacokinetic behavior of BBR. The pharmacokinetics results demonstrate that the half-life of BBR was increased significantly from 24 h to 36 h and the inter- and intra-subject variability are decreased compared to commercial BBR tablets. The retention test results indicate that the pellet size and Eudragit^® NE30D plays an important role in retention time of the pellet, and it is found that the pellets with small particle size and high Eudragit^® NE30D coating content can stay longer in the intestine than the pellets with large particle size. All in all, BBR intestinal retention type pellets are prepared successfully in this study, and the pellets show satisfactory in vivo and in vitro behaviors.