A model to simultaneously evaluate the compressibility and compactibility of a powder based on the compression ratio

Cellulose ether and carbopol 971 based gastroretentive controlled release formulation design, optimization and physiologically based pharmacokinetic modeling of ondansetron hydrochloride minitablets

This study aims to design and optimize ondansetron (OND) gastro-retentive floating minitablets for better and prolonged control of postoperative nausea and vomiting (PONV) with improved patient compliance. Minitablets were directly compressed and encapsulated in a size 2 capsule shell with an overall dose of 24 mg. Central composite design (CCD) was applied keeping one cellulose ether derivative HPMC K15M and Carbopol 971 as variable and used as swelling and rate retarding agents. The other cellulose derivative i.e. sodium carboxymethyl cellulose, along with mannitol, sodium bicarbonate, and talc, were used in fixed quantities. The floating lag time, total floating time, swelling index, in-vitro drug release, and zero-order (RSQ value), were critical quality parameters. The optimized formulation (Fpred) was evaluated for all critical parameters, along with surface morphology, thermal stability, chemical interaction, and accelerated stability. The in silico PBPK modeling was applied to compare the bioavailability of Fpred with reference OND immediate-release tablets. The numerical optimization model predicted >90 % drug release with zero-order at 12 h. In silico PBPK modeling revealed comparable relative bioavailability of Fpred with the reference formulation. The gastroretentive floating minitablets of OND were successfully designed for prolonged emesis control in patients receiving chemotherapeutic agents.

A new insight into the mechanism of the tabletability flip phenomenon

Tabletability is an outcome of interparticulate bonding area (BA) - bonding strength (BS) interplay, influenced by the mechanical properties, size and shape, surface energetics of the constituent particles, and compaction parameters. Typically, a more plastic active pharmaceutical ingredient (API) exhibits a better tabletability than less plastic APIs due to the formation of a larger BA during tablet compression. Thus, solid forms of an API with greater plasticity are traditionally preferred if other critical pharmaceutical properties are comparable. However, the tabletability flip phenomenon (TFP) suggests that a solid form of an API with poorer tabletability may exhibit better tabletability when formulated with plastic excipients. In this study, we propose another possible mechanism of TFP, wherein softer excipient particles conform to the shape of harder API particles during compaction, leading to a larger BA under certain pressures and, hence, better tabletability. In this scenario, the BA-BS interplay is dominated by BA. Accordingly, TFP should tend to occur when API solid forms are formulated with a soft excipient. We tested this hypothesis by visualizing the deformation of particles in a model compressed tablet by nondestructive micro-computed tomography and by optical microscopy when the particles were separated from the tablet. The results confirmed that soft particles wrapped around hard particles at their interfaces, while an approximately flat contact was formed between two adjacent soft particles. In addition to the direct visual evidence, the BA-dominating mechanism was also supported by the observation that TFP occurred in the p-aminobenzoic acid polymorph system only when mixed with a soft excipient.

A Method for the Tensile Strength Prediction of Tablets with Differing Powder Plasticities

Tablets are the most commonly used dosage form in the pharmaceutical industry, and their properties such as disintegration, dissolution, and portability are influenced by their strength. However, in industry, the mixing fraction of powders to obtain a tablet compact with sufficient strength is determined based on empirical rules. Therefore, a method for predicting tablet strength based on the properties of a single material is required. The objective of this study was to quantitatively evaluate the relationship between the compression properties and tablet strength of powder mixtures. The compression properties of the powder mixtures with different plasticities were evaluated based on the force-displacement curves obtained from the powder compression tests. Heckel and compression energy analyses were performed to evaluate compression properties. During the compression energy analysis, the ratio of plastic deformation energy to elastic deformation energy (Ep/Ee) was assumed to be the plastic deformability of the powder. The quantitative relationship between the compression properties and tensile strength of the tablets was investigated. Based on the obtained relationship and the compression properties of a single material, a prediction equation was put forward for the compression properties of the powder mixture. Subsequently, a correlation equation for tablet strength was proposed by combining the values of K and Ep/Ee obtained from the Heckel and compression energy analyses, respectively. Finally, by substituting the compression properties of the single material and the mass fraction of the plastic material into the proposed equation, the tablet strength of the powder mixture with different plastic deformabilities was predicted.

Cylindrical granules in the development of mesalazine solid formulations (Ⅰ): Physical properties, compression behaviors, and tableting performances

Cylindrical granules have been employed in the pharmaceutical industry. However, to our knowledge, the study on the compressibility and tabletability of cylindrical granules has not been reported. This study aimed to explore the effects of the physical properties of cylindrical granules on the compression behaviors and the tableting performances, with mesalazine (MSZ) as a model drug. First, the six formulations of MSZ cylindrical granules were extruded by changing the ethanol proportion in the binder. Then, the physical characteristics of MSZ cylindrical granules were systematically studied. Subsequently, the compressibility and tabletability were evaluated using different mathematic models. It was worth noting that highly porous cylindrical granules possessed favorable compressibility and good tabletability due to the increased pore volume, reduced density, and decreased fracture forces. Finally, dissolution tests were conducted and highly porous granules showed higher dissolution rates than the less porous ones, but an opposite trend was observed for the corresponding tablets. This study proved the importance of physical properties in the tableting process of cylindrical granules and provided strategies to improve their compressibility and tabletability.

Attribute transmission and effects of diluents and granulation liquids on granule properties and tablet quality for high shear wet granulation and tableting process

This study aims to examine (i) the effect of diluent types (lactose monohydrate, corn starch, and microcrystalline cellulose) and granulation liquids (20% polyvinylpyrrolidone-k30, 65% alcohol, and dispersion containing 40% model drug- Pithecellobium clypearia Benth extracted powder) on granule properties and tablet quality for high shear wet granulation and tableting (HSWG-T) and, more importantly, (ii) the attribute transmission in the process. In general, the impact of diluents on granule properties and tablet quality was more dominant than that of granulation liquids. Attribute transmission patterns were revealed as follows. The granules' ISO. Roundness and density correlated with raw material (i.e., model drug, diluent, and/or granulation liquid) properties such as density and viscosity. The granules' compressibility parameter a correlated with the granules' Span, and parameter y₀ correlated with the granules' flowability and friability. Compactibility parameters k_a and k_b correlated mainly with granule flowability and density, and parameter b correlated significantly and positively with tablet tensile strength. The compressibility correlated negatively with tablet solid fraction (SF) and friability, while the compactibility correlated positively with tablet disintegration time. Moreover, the rearrangement and elasticity of granules correlated positively with SF and friability, respectively. Overall, this study provides some guides for achieving high-quality tablets via HSWG-T.

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.

A new direct compression mechanism of structural transition in Poria cocos extract composite particles

The structural transition to generate amorphous translucent grains in Poria cocos dry extract (PCE) composite particles was found and studied as a new direct compression mechanism. The pressure and displacement sensing techniques were used to obtained stress-strain profiles during compression. The Exponential function, Kawakita model, Shapiro model and Heckel model were used to analysis mechanical properties of powders. 12 parameters derived from compression models and powder physical properties were applied to partial least squares method (PLS) for analyzing powder compression mechanism. It was found that only the oven-dried PCE composite particles undergoes the structural transition and generate translucent grains scattered and embedded in tablet, and these tablets have excellent mechanical stability. The structural transition in plant dry extract as the PCE composite particles could be exploited to improve powder compression and tabletability.

Improvements on multiple direct compaction properties of three powders prepared from Puerariae Lobatae Radix using surface and texture modification: comparison of microcrystalline cellulose and two nano-silicas

It has been reported that hydrophilic nano-silica (N) markedly improved direct compaction (DC) properties of Zingiberis Rhizoma alcoholic extract. This study aims to examine the broader scope and generality of the previous work by investigating (i) three powders, i.e., the directly pulverized product, ethanol extract, and water extract prepared from the same medicinal herb-Puerariae Lobatae Radix (named DP, EE, and WE) and (ii) the effects on their DC properties of co-processing with N, hydrophobic nano-silica (BN), or microcrystalline cellulose (C). Unexpectedly, C provided the best improvement on tabletability for WE, while N for both DP and EE. More importantly, only N could move all parent powders to a regime suitable for DC, and BN rather than C enabled parent WE to be directly compressed. Typically, 6/9 N-modified powders simultaneously met the requirements of DC on bulk density, flowability, and tablet tensile strength (σ_t). Principal component analysis indicated that DC properties were mainly governed by flowability and texture properties. The partial least-squares regression model revealed that flowability, texture parameters, and deformation behavior of powders were dominating factors impacting tablet σ_t and solid fraction. Overall, the findings are promising for the manufacture of high drug loading tablets of herbs by DC.

Design and evaluation of in vivo bioavailability in beagle dogs of bilayer tablet consisting of immediate release nanosuspension and sustained release layers of rebamipide

The purpose of this study was to develop a once-daily, bilayer matrix tablet with immediate (IR) and sustained release (SR) layers of poorly water-soluble and absorption site dependent rebamipide (RBM) to substitute three times a day IR tablet. Owing to the pH-dependent poor water solubility of RBM in low pH condition, salt-caged nanosuspensions (NSPs) consisting of RBM and poloxamer 407 (POX 407) or poloxamer 188 (POX 188) were prepared using an acid-base neutralization method to increase the dissolution rate, which was subsequently applied to the immediate-release (IR) layer. Polyethylene oxide (PEO) with different molecular weights (PEO 100,000 and PEO 5,000,000) and hydroxypropyl methylcellulose 4000 (HPMC 4000) were then investigated as SR agents to incorporate into the SR layer with pure RBM via wet granulation method. The dissolution profile of the optimized bilayer tablet having 50% IR and 50% SR layer of 300 mg RBM showed that the IR layer could rapidly disintegrate in pH 1.2 buffer solution within 2 h, reaching 50% of drug release from the tablet, followed by an extended drug release from the SR layer in pH 6.8 buffer over 24 h. An in vivo pharmacokinetic study was carried out in beagle dogs to compare the optimal formulation (300 mg RBM bilayer tablet) and the commercial tablet (Mucosta® 100 mg) as a reference. Unexpectedly, despite enhanced dissolution rate in a controlled manner, a designed bilayer tablet had no dose- and dosage form dependent in vivo bioavailability in beagle dogs as compared with IR 100 mg RBM reference tablet. It was evident that solubility in low pH condition, gastric residence time and absorption site of RBM should be carefully considered for designing specific SR or gastroretentive dosage form to improve therapeutic outcomes.

A new parameter for characterization of tablet friability based on a systematical study of five excipients

In this paper, a new parameter highly relevant to tablet friability is proposed based on a systematical study of the tablet quality attributes and texture performances of five different direct compression excipients, including microcrystalline cellulose, starch, lactose, mannitol, and dicalcium phosphate anhydrous. The new parameter, named Strain/Stress Max, could indicate the tablet's ability against external force to maintain integrity. It was directly obtained from the diametrical breaking test which is extensively used to assess tablet mechanical strength, and thus no extra work is required. The values varied significantly among the tablets formed by materials with different mechanical properties under the same compression pressure. A design space was developed to achieve <1% tablet friability at various combinations of Strain/Stress Max and tensile strength. Additionally, data from binary mixture tablets validated the availability of the constructed design space. And the upper limit of Strain/Stress Max value was advisable for 1.5 MPa^-1 for pharmaceutical tablets. In conclusion, the new parameter and design space are available for fast identification of the tablets with acceptable friability to facilitate the development of tablet formulation using as few active pharmaceutic ingredients as possible.

Texture and surface feature-mediated striking improvements on multiple direct compaction properties of Zingiberis Rhizoma extracted powder by coprocessing with nano-silica

The study aims to markedly improve direct compaction (DC) properties of Zingiberis Rhizoma extracted powder (ZR) by modifying its texture and surface properties with nano-silica (NS). A wet coprocessing method was applied to evenly distribute up to 33.3% NS to ZR. To clarify uniqueness of NS, microcrystalline cellulose (MCC), a superior filler-binder in DC, was used as control. Coprocessed particles and physical mixtures (PMs) were comprehensively evaluated for surface features, micromeritic properties, and texture and compacting parameters. Compared to MCC, NS could more significantly modify the texture and surface features of ZR (e.g., hardness, cohesiveness, yield pressure, and nanoscaled surface roughness) via coprocessing, resulting in more striking improvements on multiple DC properties of ZR, including tabletability, flowability, lubricant sensitivity, hygroscopicity, etc. Especially, tensile strength (σ_t) of coprocessed ZR-NS (1:0.5) tablets was 4.62 and 3.22 times that of ZR and ZR-MCC counterparts pressed at 210 MPa, respectively. Moreover, percolation thresholds of σ_t enhancement were observed for ZR-NSs, but not for ZR-MCCs. Evaluation by the SeDeM expert system indicated that some ZR-NSs (but no ZR-MCCs) were qualified for DC. Collectively, coprocessing with NS by liquid dispersion appears to be a novel, effective, and pragmatic option for DC of drugs like ZR.