Predictive model for tensile strength of pharmaceutical tablets based on local hardness measurements

Successful Formulation Window for the design of pharmaceutical tablets with required mechanical properties

Pharmaceutical tablet formulations combine the active ingredient with processing aids and functional components. This paper evaluates compressibility based predictive models for binary and ternary formulations to establish an acceptable range of tablet compression parameters that satisfy prescribed quality target criteria for tablets including minimum tablet strength and processing constraints such as maximum ejection stress and maximum compaction pressure. The concept of Successful Formulation Window (SFW) is introduced. A methodology is proposed to determine the SFW for a given formulation based on compaction simulator data collected for individual formulation components. The methodology is validated for binary and ternary mixtures and lubricated formulations. The SFW analysis was developed to support tablet formulation design to meet mechanical requirements.

Development of a simple in-die method for determination of capping tendency in rotary tableting machines

A rotary tableting machine is used for the continuous tableting process. Tableting conditions often result in capping, leading to serious problems during production. Several studies have been conducted to predict the tablet capping tendency. However, as most previous studies were conducted using a compaction simulator, there is a lack of technology that can be readily applied during actual production. Therefore, the present study aimed to develop a novel method for predicting tablet capping in a rotary tableting machine. We hypothesized that capping occurs when residual stress of the tablet inside a die exceeds the critical stress immediately before ejection. Residual stress was evaluated by measuring the in-line die-wall pressure in a rotary tableting machine. Additionally, critical stress was estimated from the tablet strength inside the die using the Rumpf's equation. The critical and residual stresses were compared to determine the capping tendency to some extent. The findings of this study will substantially contribute to the rapid detection of tablet capping during tablet production.

Systematic study of paracetamol powder mixtures and granules tabletability: Key role of rheological properties and dynamic image analysis

The aim of this systematic study was to analyze the granulometric and rheological behavior of tableting mixtures in relation to tabletability by single tablet and lab-scale batch compression with an eccentric tablet machine. Three mixtures containing 33, 50, and 66% of the cohesive drug paracetamol were prepared. The high compressibility of the powder mixtures caused problems with overcompaction or lamination in the single tablet compression method; due to jamming of the material during the filling of the die, the lab-scale batch compression was impossible. Using high shear granulation, the flow properties and tabletability were adjusted. A linear relationship between the span of granules and the specific energy measured by FT4 powder rheometer was detected. In parallel, a linear relationship between conditioned bulk density and the tensile strength of the tablets at lab-scale batch tableting was noted. The combination of dynamic image analysis and powder rheometry was useful for predicting the tabletability of pharmaceutical mixtures during the single tablet (design) compression and the lab-scale batch compression.

Tableting model assessment of porosity and tensile strength using a continuous wet granulation route

This paper presents a comprehensive assessment of the most widely used tablet compaction models in a continuous wet granulation tableting process. The porosity models, tensile strength models and lubricant models are reviewed from the literature and classified based on their formulations i.e. empirical or theoretical and applications, i.e. batch or continuous. The majority of these models are empirical and were initially developed for batch tabletting process. To ascertain their effectiveness and serviceability in the continuous tableting process, a continuous powder processing line of Diamond Pilot Plant (DiPP) installed at The University of Sheffield was used to provide the quantitative data for tablet model assessment. Magnesium stearate (MgSt) is used as a lubricant to investigate its influence on the tensile strength. Whilst satisfactory predictions from the tablet models can be produced, a compromise between the model fidelity and model simplicity needs to be made for a suitable model selection. The Sonnergaard model outperforms amongst the porosity models whilst the Reynolds model produces the best goodness of fitting for two parameters fitting porosity models. An improved tensile strength model is proposed to consider the influence of powder size and porosity in the continuous tableting process.

Core in Cup Ethylmorphine Hydrochloride Tablet for Dual Fast and Sustained Pain Relief: Formulation, Characterization, and Pharmacokinetic Study

Ethylmorphine hydrochloride (EtM) is a derivative of morphine used as analgesic to treat severe pain in case of cancer and bone injury. This study aimed to formulate and evaluate core in cup tablets containing 2 doses of EtM, the cup was formulated as lyophilized oro-dispersible tablet (ODT) for immediate release (IR), and the core was formulated as directly compressed tablet for sustained release (SR). Factorial design was adopted for the optimization of tablets prepared via lyophilized form and direct compression techniques: a 4¹.2² design was used for the former, while a 3² one was used for the latter. All prepared tablets showed acceptable physical properties which were in accordance with pharmacopeial standards. Two lyophilized ODTs (F9 and F10) formulae were selected as the cup for instant release. While one directly compressed tablet formula (S6) was selected based on the in vitro release profile to represent the sustained core, the outcome was 2 core in cup tablets, namely B1 and B2 which were evaluated for their in vivo absorption and showed a maximum plasma concentration (Cp_max) of 354.12 ± 17.55 ng/mL and 350.82 ± 12.15 ng/mL respectively attained after 3.0 h which were twofolds significantly higher in comparison to the market tablet with Cp_max of only 172.05 ± 12.53 ng/mL attained after 2.20 ± 0.24 h.

Photocurable Bioinks for the 3D Pharming of Combination Therapies

Combination therapies mediate drug synergy to improve treatment efficacy and convenience, leading to higher levels of compliance. However, there are challenges with their manufacturing as well as reduced flexibility in dosing options. This study reports on the design and characterization of a polypill fabricated through the combination of material jetting and binder jetting for the treatment of hypertension. The drugs lisinopril and spironolactone were loaded into hydrophilic hyaluronic acid and hydrophobic poly(ethylene glycol) (PEG) photocurable bioinks, respectively, and dispensed through a piezoelectric nozzle onto a blank preform tablet composed of two attachable compartments fabricated via binder jetting 3D printing. The bioinks were photopolymerized and their mechanical properties were assessed via Instron testing. Scanning electron microscopy (SEM) was performed to indicate morphological analysis. The polypill was ensembled and drug release analysis was performed. Droplet formation of bioinks loaded with hydrophilic and hydrophobic active pharmaceutical ingredients (APIs) was achieved and subsequently polymerized after a controlled dosage was dispensed onto preform tablet compartments. High-performance liquid chromatography (HPLC) analysis showed sustained release profiles for each of the loaded compounds. This study confirms the potential of material jetting in conjunction with binder jetting techniques (powder-bed 3D printing), for the production of combination therapy oral dosage forms involving both hydrophilic and hydrophobic drugs.

Photocurable poly(ethylene glycol) as a bioink for the inkjet 3D pharming of hydrophobic drugs

Binder jetting and material extrusion are the two most common additive manufacturing techniques used to create pharmaceutical tablets. However, their versatility is limited since the powder component is present throughout the dosage forms fabricated by binder jet 3D printing and material extrusion 3D printing requires high operating temperatures. Conversely, material jetting allows for compositional control at a voxel level and can dispense material at room temperature. Unfortunately, there are a limited number of materials that are both printable and biocompatible. Therefore, the aim of this study was to engineer photocurable bioinks that are suitable for hydrophobic active pharmaceutical ingredients and have rapid gelation times upon visible light exposure. The resulting bioinks were comprised of poly(ethylene glycol) diacrylate (250 Da) as the crosslinkable monomer, Eosin Y as the photoinitiator, and methoxide-poly(ethylene glycol)-amine as the coinitiator. Additionally, poly(ethylene glycol) (200 Da) was added as a plasticizer to modulate the drug release profiles, and Naproxen was used as the model drug due to its high hydrophobicity. Various bioink formulations were dispensed into the bottom half of blank preform tablets - made via direct compression - using a piezoelectric nozzle, photopolymerized, and capped with the top half of the preform tablet to complete the pharmaceutical dosage form. Results from the release studies showed that drug release can be modulated by both the percent of poly(ethylene glycol) diacrylate in the formulation and the light exposure time used to cure the bioinks. These bioinks have the potential to expand the library of materials available for creating pharmaceutical tablets via inkjet printing with personalized drug dosages.

Influences of novel microwave drying on dissolution of new formulated naproxen sodium

Drying of a pharmaceutical composition is an important step during its processing, which can affect its quality attributes including its texture, dispersion of the drug within the formulation, drug dissolution kinetics and eventually the drug's efficacy. This study presents the influence of varying drying techniques on the textural properties of the wet granulated formulation consisting of the drug naproxen sodium (NapSod) during the drying process. A new pharmaceutical formulation consisting of the NapSod drug was prepared by wet granulation and dried by novel microwave drying (MW), freeze drying (FD), vacuum drying (VD), and convective drying (CD) techniques before being processed in the form of tablets. The dissolution rate of NapSod from the tablet was measured in gastric (pH = 1.3) and intestinal fluid (pH = 6.8) mediums. The drug release was found to be influenced by the specific surface area, size distribution and the crystalline structure of dried particles, which were found to vary with the type of drying technique used as confirmed by the results of XRD, FTIR, SEM and particle size analyses. This study shows that using microwave technique to dry pharmaceutical granules containing a polar drug, such as NapSod, is an efficient and economical process, which can maintain the drug release at an appropriate rate to realize its desired pharmaceutical effect.

Novel microwave mediated drying of naproxen sodium has been shown as an efficient drying technique as well as exhibiting a critical role in improving the dissolution kinetics.

Quality by Design (QbD) approach to optimize the formulation of a bilayer combination tablet (Telmiduo®) manufactured via high shear wet granulation

A bilayer tablet, which consisted of telmisartan and amlodipine besylate, was formulated based on a Quality by Design (QbD) approach. The control and response factors were determined based on primary knowledge and the target values of the control tablet (Twynsta^®). A D-optimal mixture design was used to obtain the optimal formulations in terms of D-mannitol, crospovidone, and MCC for the telmisartan layer, and CCM-Na, PVP K25, and Prosolv for the amlodipine layer. The quantitative effects of the different formulation factors on the response factors were accurately predicted using the equations of best fit and a strong linearity was observed between the predicted and actual values of the response factors. The optimized bilayer tablet was obtained using a numeric optimization technique and was characterized compared with a control (Twynsta^®) by using various physical evaluations and in vivo pharmacokinetic parameters. The physical stability of Telmiduo^® was greater than that of Twynsta^® owing to the improvement of formulation factors. The in vivo pharmacokinetic parameters suggested that Telmiduo^® might have pharmaceutical equivalence and bioequivalence with Twynsta^®. Therefore, the bilayer tablet that consisted of telmisartan and amlodipine besylate could be produced using a more economical and simpler method than that used to produce Twynsta^®. Moreover, the suitability of QbD for effective product development in the pharmaceutical industry was shown.