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Increasing access to additive manufacturing technologies utilising easily available desktop devices opened novel ways for formulation of personalized medicines. It is, however, challenging to propose a flexible and robust formulation platform which can be used for fabrication of tailored solid dosage forms composed of APIs with different properties (e.g., hydrophobicity) without extensive optimization. This manuscript presents a strategy for formulation of fast dissolving tablets using binder jetting (BJ) technology. The approach is demonstrated using two model APIs: hydrophilic quinapril hydrochloride (QHCl, logP = 1.4) and hydrophobic clotrimazole (CLO, logP = 5.4). The proposed printing method uses inexpensive well known and easily available FDA approved pharmaceutical excipients. The obtained model tablets had uniform content of the drug, excellent mechanical properties and highly porous structure resulting in short disintegration time and fast dissolution rate. The tablets could be scaled and obtained in predesigned shapes and sizes. The proposed method may find its application in the early stages of drug development where high flexibility of the formulation is required and the amount of available API is limited.

A study of the effect of a short-chain branching distribution (SCBD) on the phase behavior of linear low density polyethylene (LLDPE) was conducted. The perturbed chain-SAFT equation of state was the underlying thermodynamic model chosen for the study; the branched polyolefins were described using a simple modeling concept previously proposed by Dominik and Chapman.(1) To isolate the effect of the SCBD on phase behavior, the copolymer systems were considered monodisperse in molecular weight. The study revealed that, in the case of low to moderate values of the polydispersity index of the SCBD, the compositional polydispersity affected the phase behavior at low polymer concentrations only. When the polydispersity index of the SCBD is high, or, in other words, when the difference in branch content between the components of the distribution is significant, additional phases appear. The formation of multiple phases results from the incompatibility of branched and linear polymers. Similar observations were mad...

A perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state has been extended to include a crossover correction, based on White’s work with renormalization-group (RG) theory, that accounts for the contributions of long-wavelength density fluctuations in the critical region. In the critical region, the improved crossover equation of state provides the correct nonclassical critical exponents. Away from the critical region, the crossover equation reduces to the original PC-SAFT equation, therefore maintaining the accuracy of PC-SAFT in this region. No modifications to the original PC-SAFT molecular parameters are necessary, therefore allowing for an accurate description of thermodynamic properties from the triple point to the critical point. Excellent agreement with vapor−liquid equilibrium experimental data for the n-alkane family is obtained inside and outside the critical region, and all critical constants Tc, Pc, and ρc are calculated within their respective experimental errors. Th...

Using a density functional theory (DFT) based on Rosenfeld's formalism for hard spheres, we investigate the influence of model solutes of different sizes on the structure and interfacial properties...

The dimer-chain term proposed by Ghonasgi and Chapman [J. Chem. Phys. 1994, 100, 6633−6639], which accounts for the chain connectivity, is used in conjunction with the perturbed-chain dispersion term proposed by Gross and Sadowski [Ind. Eng. Chem. Res. 2001, 40, 1244−1260] to form a new equation of state (EOS) for polyatomic fluids. The new EOS is applied to the homologous series of n-alkanes, mixtures of long- and short-chain alkanes, and polymers. The predictive and extrapolative capabilities of the model are demonstrated through comparisons with experimental data for pure components and mixtures. The new EOS provides an accurate description of liquid densities over the entire range of temperature, including the critical region. The predictions for mixtures of long- and short-chain alkanes are in excellent agreement with experimental data without using a binary interaction parameter. The description of the phase behavior of polymer solutions is improved, in comparison to perturbed-chain−statistical asso...

Bulk and interfacial properties of n-alkanes and polymers are modeled in the framework of the interfacial statistical associating fluid theory (iSAFT) density functional theory (DFT). The theory reduces to an equivalent of the SAFT equation of state in the bulk, thus making possible the modeling of both bulk and interfacial properties with a single set of parameters. The performance of iSAFT is illustrated through comparisons of the theory predictions with molecular simulation as well as experimental data for vapor−liquid surface tension. The formulation of iSAFT DFT preserves the computational efficiency of an atomic DFT, thus enabling the theory to deal with molecules comprising hundreds or even thousands of segments, such as the polystyrene and polyethylene included in the present work.

This article presents a simple thermodynamic model for branched polyolefin systems in the framework of the PC-SAFT equation of state. The physical properties of the polymeric material can be tailored to a customer's specific needs by the choice of the α-olefin comonomer and the adjustment of its content in the chain. The model efficiently captures the effect of chain branching, comonomer type, and branching density on the phase behavior of polyolefin solutions. Since few adjustable parameters are required, it can be applied to systems for which little experimental data is available. The model parameters follow sensible trends, demonstrating its robustness for extrapolations and parameter prediction. Finally, the simple formulation facilitates its incorporation into commercial software for phase equilibria calculations.

The Perturbed-Chain SAFT (PC-SAFT) equation of state is applied to model phase equilibria and the thermodynamic properties of ethers and esters. A systematic study of these two homologous series is conducted, and the performance of two different approaches for including the dipolar interactions in the equation of state is evaluated. Although both Polar PC−SAFT [dipolar contribution due to Jog and Chapman, Mol. Phys. 1999, 97, 307−319] and PC−SAFT + Fischer [dipolar contribution by Saager and Fischer, Mol. Simul. 1991, 6, 27−49] yield similar results for the considered systems, the parameters of Polar PC−SAFT are more physically meaningful than those of PC−SAFT + Fischer. Consequently, Polar PC−SAFT is considered to be more suitable for extrapolations, and for application to components that have multiple polar groups in the chain.

Wertheim's thermodynamic perturbation theory of first order (TPT1) is based on the approximation that the monomer–monomer distribution functions can be approximated by the reference fluid distribution functions regardless of the amount of bonding. This is remarkably accurate for chains formed by tangent spheres, but no longer valid for chains of fused spheres. This constitutes the reason for the inadequacy of TPT1 for fused sphere chains. We present a systematic modification of TPT1, the path integral perturbation method, that takes into account the variations of the distribution functions with extent of bonding. We demonstrate the accuracy of the theory for mixtures of hard spheres and diatomics over a range of extent of bonding (pure monomers to pure dimers) and degree of fusion (bond length 0–1). We found that the choice of reference fluid was decisive for the accuracy of the model's predictions. The proposed theory can accurately predict the properties of mixtures of hard spheres and diatomics, and of...

A density functional theory based on Wertheim's first order perturbation theory is developed for inhomogeneous complex fluids. The theory is derived along similar lines as interfacial statistical associating fluid theory [S. Tripathi and W. G. Chapman, J. Chem. Phys. 122, 094506 (2005)]. However, the derivation is more general and applies broadly to a range of systems, retaining the simplicity of a segment density based theory. Furthermore, the theory gives the exact density profile for ideal chains in an external field. The general avail of the theory has been demonstrated by applying the theory to lipids near surfaces, lipid bilayers, and copolymer thin films. The theoretical results show excellent agreement with the results from molecular simulations.