Pharmaceutical Lauryl Sulfate Salts: Prevalence, Formation Rules, and Formulation Implications

Development and Evaluation of Lactose-Free Single-Unit and Multiple-Unit Preparations of a BCS Class II Drug, Rivaroxaban

Background/Objectives: The aim of the present study was to develop lactose-free formulations of rivaroxaban, a novel oral anticoagulant used for the treatment and prevention of blood clotting. As a BCS Class II drug, rivaroxaban is characterized by poor solubility in aqueous media, posing a significant formulation challenge. Methods: To address this, phosphate-based excipients were employed to prepare both traditional single-unit dosage forms (tablets) and modern multiple-unit pellet systems (MUPS). These formulations were successfully developed and thoroughly evaluated for their physical properties and performance. Results: The resulting formulations demonstrated very good mechanical strength, including appropriate hardness and friability, alongside strong chemical stability. Their dissolution profiles met the requirements of the compendial monograph for Rivaroxaban Tablets and were comparable to those of the reference product, Xarelto® film-coated tablets. Conclusions: This study shows the potential for producing effective, stable, and patient-friendly medications that meet the needs of contemporary society, where an increasing number of individuals suffer from lactose intolerance or seek vegan-friendly alternatives.

Therapeutic coordination polymers: tailoring drug release through metal-ligand interactions

Developing tunable materials which exhibit sustained drug release is a considerable challenge. Herein, we report the concept of Therapeutic Coordination Polymers (TCPs); non-porous coordination polymers constructed from biocompatible components which demonstrate tunable zero-order drug release kinetics upon degradation of metal-ligand bonds. TCPs were constructed from three principal components: (i) a cationic metal center (M = Mg2+, Mn2+, Zn2+, or Cu2+); (ii) an anionic drug (Diclofenac); and (iii) an alkyl bis-imidazole organic ligand which behaves as a "linker" between metal centers. Most drug-release materials, such as amorphous polymer dispersions, or metal-organic frameworks rely on a diffusion-based mechanism for drug release, but the degradation-controlled release of drugs from non-porous one-periodic coordination polymers has been largely unexplored. TCPs described herein exhibit a high wt% of pharmaceutical (>62%), tailorable zero-order drug release rate kinetics which span over three orders of magnitude, and stimuli-responsive drug release behavior making them well suited for extended drug-release applications.

Discriminative Dissolution Method Development Through an aQbD Approach

Using a one-factor-at-a-time approach for dissolution method and discrimination analysis can be time-consuming and may not yield the optimal and discriminative method. To address this, we have developed a two-stage workflow for the dissolution method development followed by demonstration of discrimination power through an analytical Quality by Design (aQbD) approach. In the first stage, an optimal dissolution method was achieved by determining the method operable design region (MODR) through a design of experiment study of the high-risk method-related parameters. In the second stage, we established a Formulation-Discrimination Correlation Diagram strategy to examine the method discrimination capability, through which one can determine the method discriminative design region (MDDR) and visualize the impact of each formulation parameter and their interactions on dissolution. The application of aQbD principles into a workflow provides a scientific-driven guidance for robust method development and demonstrating discrimination power for dissolution methods.

Telomerase and hallmarks of cancer: An intricate interplay governing cancer cell evolution

Transformed cells must acquire specific characteristics to be malignant. Weinberg and Hanahan characterize these characteristics as cancer hallmarks. Though these features are independently driven, substantial signaling crosstalk in transformed cells efficiently promotes these feature acquisitions. Telomerase is an enzyme complex that maintains telomere length. However, its main component, Telomere reverse transcriptase (TERT), has been found to interact with various signaling molecules like cMYC, NF-kB, BRG1 and cooperate in transcription and metabolic reprogramming, acting as a strong proponent of malignant features such as cell death resistance, sustained proliferation, angiogenesis activation, and metastasis, among others. It allows cells to avoid replicative senescence and achieve endless replicative potential. This review summarizes both the canonical and noncanonical functions of TERT and discusses how they promote cancer hallmarks. Understanding the role of Telomerase in promoting cancer hallmarks provides vital insight into the underlying mechanism of cancer genesis and progression and telomerase intervention as a possible therapeutic target for cancer treatment. More investigation into the precise molecular mechanisms of telomerase-mediated impacts on cancer hallmarks will contribute to developing more focused and customized cancer treatment methods.

Effects of Additives on the Physical Stability and Dissolution of Polymeric Amorphous Solid Dispersions: a Review

Polymeric amorphous solid dispersion (ASD) is a popular approach for enhancing the solubility of poorly water-soluble drugs. However, achieving both physical stability and dissolution performance in an ASD prepared with a single polymer can be challenging. Therefore, a secondary excipient can be added. In this paper, we review three classes of additives that can be added internally to ASDs: (i) a second polymer, to form a ternary drug-polymer-polymer ASD, (ii) counterions, to facilitate in situ salt formation, and (iii) surfactants. In an ASD prepared with a combination of polymers, each polymer exerts a unique function, such as a stabilizer in the solid state and a crystallization inhibitor during dissolution. In situ salt formation in ASD usually leads to substantial increases in the glass transition temperature, contributing to improved physical stability. Surfactants can enhance the wettability of ASD particles, thereby promoting rapid drug release. However, their potential adverse effects on physical stability and dissolution, resulting from enhanced molecular mobility and competitive molecular interaction with the polymer, respectively, warrant careful consideration. Finally, we discuss the impact of magnesium stearate and inorganic salts, excipients added externally upon downstream processing, on the solid-state stability as well as the dissolution of ASD tablets.

Surfactant Mediated Accelerated and Discriminatory In Vitro Drug Release Method for PLGA Nanoparticles of Poorly Water-Soluble Drug

In vitro drug release testing is an important quality control tool for formulation development. However, the literature has evidence that poly-lactide-co-glycolide (PLGA)-based formulations show a slower in vitro drug release than a real in vivo drug release. Much longer in vitro drug release profiles may not be reflective of real in vivo performances and may significantly affect the timeline for a formulation development. The objective of this study was to develop a surfactant mediated accelerated in vitro drug release method for the PLGA nanoparticles (NPs) of a novel chemotherapeutic agent AC1LPSZG, a model drug with a poor solubility. The Sotax USP apparatus 4 was used to test in vitro drug release in a phosphate buffer with a pH value of 6.8. The sink conditions were improved using surfactants in the order of sodium lauryl sulfate (SLS) < Tween 80 < cetyltrimethylammonium bromide (CTAB). The dissolution efficiency (DE) and area under the dissolution curve (AUC) were increased three-fold when increasing the CTAB concentration in the phosphate buffer (pH 6.8). Similar Weibull release kinetics and good linear correlations (R2~0.99) indicated a good correlation between the real-time in vitro release profile in the phosphate buffer (pH 6.8) and accelerated release profiles in the optimized medium. This newly developed accelerated and discriminatory in vitro test can be used as a quality control tool to identify critical formulation and process parameters to ensure a batch-to-batch uniformity. It may also serve as a surrogate for bioequivalence studies if a predictive in vitro in vivo correlation (IVIVC) is obtained. The results of this study are limited to AC1LPSZG NPs, but a similar consideration can be extended to other PLGA-based NPs of drugs with similar properties and solubility profiles.

Effect of sodium lauryl sulfate-mediated gelation on the suppressed dissolution of crystalline lurasidone hydrochloride and a strategy to mitigate the gelation

In dissolution test, the surfactant sodium lauryl sulfate (SLS) is usually added to increase the dissolution of insoluble drugs and achieve the sink condition. However, the current study found that 0.1 % SLS would significantly decrease the dissolution of crystalline lurasidone hydrochloride (LH, a BCS Ⅱ drug). The aim of this study was to clarify the mechanism of this unexpected phenomenon and explore a strategy for mitigating the negative effect of SLS on the dissolution of LH. Sample characterizations (such as PLM, DSC, PXRD, IR and NMR) confirmed that the insoluble single-phase amorphous LH-SLS complex (with a single T_g at 35.2 °C) formed during dissolution in 0.1 % SLS aqueous solution via electrostatic interaction, tetrel bond interaction, and hydrophobic effect. Due to the plasticization effect of water, the transition of amorphous LH-SLS from its glassy state to viscous supercooled liquid state led to the gel formation, and suppressd the dissolution of LH. Meanwhile, the solubility curve of LH in SLS aqueous solution at various concentrations exhibited an unusual V-shaped feature, with the CMC value of SLS serving as the inflection point, since the gel degree was attenuated due to the micelle solubilization of SLS. Additionally, an innovative strategy was developed to alleviate the inhibiting effect of SLS on LH dissolution based on the potential competitive interactions. This study not only enriches the internal mechanism of surfactant-inhibited drug dissolution but also informs an effective strategy to mitigate the gelation.

Vitamin C Improves Dasatinib Concentrations Under Hypochlorhydric Conditions of the Simulated Stomach Duodenum Model

PURPOSE

pH-dependent drug-drug interactions (DDIs) with poorly soluble, weakly basic drugs may lead to clinical implications. Dasatinib is a tyrosine kinase inhibitor with reduced absorption in patients on acid-reducing agents (ARAs). The objective of this study is to investigate the influence of gastric pH on dasatinib supersaturation and determine if vitamin C (L-ascorbic acid) can improve dasatinib concentrations under simulated hypochlorhydric gastric conditions.

METHODS

A dynamic, in vitro, multi-compartment, simulated stomach duodenum (SSD) model mimicking fluid volumes and transfer rates was used to investigate the concentration of BCS class IIb drugs versus time curves. Dasatinib and lamotrigine were explored under normal, fasted, simulated gastric fluids (pH 2) (FaSGF), hypochlorhydric simulated gastric fluids (pH 4.5) (FaSGF_hypo) and FaSGF_hypo with 1000 mg of vitamin C.

RESULTS

Significant supersaturation of dasatinib was observed in the duodenum compartment of the SSD model in FaSGF. A 90% reduction in dasatinib AUC_∞ was observed in FaSGF_hypo. Upon addition of vitamin C to FaSGF_hypo, drug concentrations were restored to those observed in FaSGF. Lamotrigine AUC_∞ in the duodenal compartment were similar in both FaSGF and FaSGF_hypo. The in vitro trends observed for dasatinib and lamotrigine are reflective of the trends observed in vivo in subjects receiving treatment with ARAs.

CONCLUSIONS

The SSD model serves as a good in vitro tool for assessing the effect of pH-dependent DDIs on bioavailability of weakly basic drugs with solubility/ dissolution limited absorption. Vitamin C provides a promising approach for improving bioavailability of poorly soluble, weakly basic drugs in hypochlorhydric patients.

Profound effects of gastric secretion rate variations on the precipitation of erlotinib in duodenum - an in vitro investigation

Using an artificial stomach and duodenum (ASD), we investigated the pH-dependent precipitation of erlotinib (ERL) during dissolution in the gastrointestinal (GI) tract by varying the rate of gastric fluid secretion (GFS). Results show that decreasing GFS rate from 2.5 to 0.5 mL/min leads to an increased degree of supersaturation in the duodenum fluid due to elevated pH, resulting in precipitation of ERL and a reduced area under the curve (AUC) of the concentration - time profiles from 14,000 to 3,000 (μg‧min)/mL. Such a change in AUC is expected to lower the bioavailability of ERL, a BCS II drug, in patients with a low GFS. This example demonstrates the potential use of ASD as an effective tool for guiding the efficient development of robust tablet formulations by better understanding the impact of GI tract pH on the fate of drugs in the duodenal fluid.

Formulation strategies for mitigating dissolution reduction of p-aminobenzoic acid by sodium lauryl sulfate through diffusion layer modulation

The use of the surfactant, sodium lauryl sulfate (SLS), instead of enhancing drug dissolution, deteriorates the dissolution of some alkaline drugs through forming poorly soluble lauryl sulfate salts. The thermodynamic driving force for precipitation of such salts is the ratio of ion product in solution (Q) to the solubility product of the salt (K_sp). In this work, we have examined two formulation strategies for mitigating the negative effect of SLS on the dissolution of p-aminobenzoic acid (PABA) by reducing the Q value of its LS salt in the diffusion layer: 1) introducing alkalizing excipient, Na₃PO₄, to reduce the concentration of PABAH⁺ by elevating the microenvironment pH, and 2) introducing NaCl to reduce the LS^- monomer concentration by depressing the critical micelle concentration (CMC) of SLS.