An Investigation into the Influence of Process Parameters and Formulation Variables on Compaction Properties of Liquisolid Systems

Data-driven insights into the properties of liquisolid systems based on machine learning algorithms

Liquisolid systems (LS) represent a formulation approach where liquid drug or its dispersion is transformed into a powder with good flowability and compactibility, leading to enhanced drug dissolution and bioavailability. Many research groups have focused on the preparation and investigation of LS, leading to a higher need for comprehensive evaluation of factors impacting LS characteristics. The aim of this work was to investigate the applicability of machine learning algorithms in the LS evaluation, using data mined from published literature, and provide an insight into critical factors governing the liquisolid system performance. The dataset was prepared using publication search engines and relevant keywords, with a total of 425 formulations included in the database. The database focused on preparation methods, formulation parameters, and liquisolid system characteristics. Subsequently, critical properties of the liquisolid system, i.e. flowability, compact hardness, and drug dissolution, were analyzed using machine learning algorithms, including Gradient Boosting, Adaptive Boosting and Random Forest. In addition to conventional preparation methods and excipients, novel technologies (fluid bed preparation, extrusion/spheronization) and materials (Neusilin®, Fujicalin®, and Syloid®) enhanced the properties of liquisolid systems. The analysis revealed that formulation factors, such as carrier and coating agent type and content, liquid phase load, model drug type and content, as well as preparation method, significantly influenced liquisolid system characteristics. The models developed exhibited high prediction accuracy when applied on test data (higher than 80 %). This indicates that the machine learning models may provide an insight into the critical attributes affecting the LS performance and may be used as a valuable tool in the development and optimization of these samples.

Design and development of Fujicalin-based axitinib liquisolid compacts for improved dissolution and bioavailability to treat renal cell carcinoma

Poor dissolution of axitinib (AXT) limits its effectiveness through the oral route. The present study investigated, prospective of liquisolid (LS) technology to improve dissolution rate and oral bioavailability of AXT to treat renal cell carcinoma. LS compacts were fabricated with PEG 200, Fujicalin SG, and Aerosil 200 as solvent, carrier, and coat material, respectively. The behavior of LS-systems during tabletting was investigated using Kawakita, Heckel, and Leuenberger analysis. LS compacts were examined for P-XRD, DSC, SEM, and in vitro drug dissolution. For optimization, a 32 full factorial design was utilized. Cell line A498 was utilized for in vitro cytotoxicity study. A bioavailability study was performed using rabbits. DSC and P-XRD analysis confirmed the transition of crystalline AXT to its partial amorphization and molecular dispersion. Consequently, LS6 demonstrated a significantly rapid drug dissolution (Q20; >99 %) than the directly compressed tablets (18.05 %). Additionally, 2.03-fold increase in oral bioavailability, and inhibited dose-dependent cell growth with 1.75-fold increased apoptosis rate. Overall, an LS6 compact consisting of 15 % AXT concentration in PEG 200 and a 20 w/w ratio of Fujicalin SG: Aerosil 200 exhibited improved formulation properties, enhanced dissolution rate, and bioavailability. Thus developed potential product may contribute low-cost production with patient-improved survival expectations.

The comparison of melt technologies based on mesoporous carriers for improved carvedilol dissolution

High-shear (HS) melt granulation and hot melt extrusion (HME) were compared as perspective melt-based technologies for preparation of amorphous solid dispersions (ASDs). ASDs were prepared using mesoporous carriers (SyloidⓇ 244FP or NeusilinⓇ US2), which were loaded with carvedilol dispersed in polymeric matrix (polyethylene glycol 6000 or SoluplusⓇ). Formulations with high carvedilol content were obtained either by HME (11 extrudates with polymer:carrier ratio 1:1) or HS granulation (6 granulates with polymer:carrier ratio 3:1). DSC and XRD analysis confirmed the absence of crystalline carvedilol for the majority of prepared ADSs, thus confirming the stabilizing effect of selected polymers and carriers over amorphous carvedilol. HME produced larger particles compared to HS melt granulation, which was in line with better flow time and Carr index of extrudates. Moreover, SEM images revealed smoother surface of ASDs obtained by HME, contributing to less obstructed flow. The rougher and more porous surface of HS granules was correlated to larger granule specific surface area, manifesting in faster carvedilol release from SyloidⓇ 244FP-based granules, as compared to their HME counterparts. Regarding dissolution, the two HS-formulations performed superior to pure crystalline carvedilol, thereby confirming the suitability of HS melt granulation for developing dosage forms with improved carvedilol dissolution.

Application of Machine-Learning Algorithms for Better Understanding the Properties of Liquisolid Systems Prepared with Three Mesoporous Silica Based Carriers

The processing of liquisolid systems (LSS), which are considered a promising approach to improving the oral bioavailability of poorly soluble drugs, has proven challenging due to the relatively high amount of liquid phase incorporated within them. The objective of this study was to apply machine-learning tools to better understand the effects of formulation factors and/or tableting process parameters on the flowability and compaction properties of LSS with silica-based mesoporous excipients as carriers. In addition, the results of the flowability testing and dynamic compaction analysis of liquisolid admixtures were used to build data sets and develop predictive multivariate models. In the regression analysis, six different algorithms were used to model the relationship between tensile strength (TS), the target variable, and eight other input variables. The AdaBoost algorithm provided the best-fit model for predicting TS (coefficient of determination = 0.94), with ejection stress (ES), compaction pressure, and carrier type being the parameters that influenced its performance the most. The same algorithm was best for classification (precision = 0.90), depending on the type of carrier used, with detachment stress, ES, and TS as variables affecting the performance of the model. Furthermore, the formulations with Neusilin® US2 were able to maintain good flowability and satisfactory values of TS despite having a higher liquid load compared to the other two carriers.

An overview on liquisolid technique: its development and applications

With its simplicity and cost-effectiveness, the liquisolid technique offers solutions for numerous formulation problems. Among these are dissolution enhancement and sustaining drug release, and the liquisolid technique dealt with both approaches. This review focuses on the latest advances in the technique. It discusses modified additives for use as carrier materials, which secure the required large surface area for enclosing liquids. The review also covers the modern liquipellet technique derived from the extrusion/palletization technique. Also, the liquiground term is introduced, combining the advantages of co-grinding with the liquisolid concept. Furthermore, several grades of Eudragits, and hydrophilic retarding polymers are mentioned to explain modes of sustaining drug release. This review sums up the liquisolid technique development and its applications recently achieved.

Liquisolid systems: Evaluation of the influence of formulation variables on the optimum liquid load

Liquisolid systems represent an emerging approach in the preparation of solid dosage forms with liquid lipophilic drug or poorly water-soluble drug solution/suspension in suitable liquid vehicle. This study addresses the lack of data regarding the compaction behavior of liquisolid systems, with the aim to investigate the influence of liquid load, carrier to coating ratio, carrier type (microcrystalline cellulose vs. spray dried calcium hydrogen phosphate, anhydrous (Fujicalin®)) on flowability and compaction properties of liquisolid systems and to determine the optimum liquid loads. Liquisolid admixtures with Fujicalin® showed notably better flowability than those with microcrystalline cellulose. An increase in carrier to coating ratio led to enhanced flowability of the admixtures. Compacts with Fujicalin® had good mechanical properties up to 24.7% liquid, while those with microcrystalline cellulose had acceptable mechanical strength up to 16.2% liquid. Liquisolid systems with Fujicalin® showed similar tabletability profiles as those with microcrystalline cellulose, despite having higher liquid content. The ejection stress values indicated that the addition of lubricant might be needed in the case of liquisolid systems with Fujicalin®. Superior properties of Fujicalin® as a carrier for liquisolid tablets were revealed, and dynamic compaction analysis was found to be a valuable tool for the assessment of compaction behavior of liquisolid systems.

Liquisolid systems as a novel approach in formulation and manufacturing of solid dosage forms: Challenges and perspectives

Liquisolid systems are a novel, promising platform for the production of solid dosage forms with a high liquid content, i.e. dispersion of the drug in a suitable, hydrophilic, non-volatile liquid vehicle or liquid drug. This technology requires conventional, but highly porous excipients (carrier and coating material in the appropriate ratio) able to absorb/adsorb liquid medication, resulting in both good flowability and acceptable compression properties. This approach has shown great potential to improve the dissolution rate and bioavailability of poorly soluble drugs, and has been recognized as a good alternative to common, more complex and expensive techniques. A variety of applications of this simple technique have been investigated recently, including the preparation of: modified release tablets, orally disintegrating tablets, solid dosage forms with liquid herbal extracts, etc. This emerging technology has numerous advantages, and the most important are: simplicity, cost-effectiveness, applicability in large scale production and environmental friendliness. However, it is accompanied by certain challenges as well, such as limited applicability in the case of highly dosed drugs. This article aims to give a comprehensive overview of recent progress regarding the potential applications of this technology, as well as to give an insight into the new liquisolid-based techniques intending to further support its commercial applicability.

The importance of the coating material type and amount in the preparation of liquisolid systems based on magnesium aluminometasilicate carrier

Albeit the preparation of liquisolid systems represents an innovative approach to enhance the dissolution of poorly soluble drugs, their broader utilization is still limited mainly due to the problematic conversion of the liquid into freely flowing and readily compressible powder. Accordingly, the presented study aims to determine the optimal carrier/coating material ratio (R value) for formulations based on magnesium aluminometasilicate (NUS2) loaded with polyethylene glycol 400. Four commercially available colloidal silica were used as coating materials in nine different R values (range of 5 - 100). The obtained results suggested that the higher R value leads to the superior properties of powder mixtures, such as better flowability, as well as compacts with higher tensile strength and lower friability. Moreover, it was observed that the type of coating material impacts the properties of liquisolid systems due to the different arrangement of particles in the liquisolid mixture. To confirm the noted dependency of R value and coating material type, the one- and two-way ANOVA, linear regression and principal component analysis (PCA) techniques were performed. In addition, a comparison of results with the properties of loaded NUS2 itself revealed that LSS with sufficient properties may be prepared even without the coating material.

Investigation into liquisolid system processability based on the SeDeM Expert System approach

Liquisolid systems are emerging formulation approach for poorly soluble drugs, based on adsorption/absorption of drug dispersion and obtaining free-flowing powder with good compressibility. SeDeM Expert System represents a powder processability evaluation method. It may provide additional insight into liquisolid systems critical quality attributes, but the contribution of this approach remains to be explored. The aims of this study were: pellet preparation by combination of liquisolid technology and water granulation/extrusion, evaluation of liquisolid based systems (pellets/admixtures) and investigation into the applicability of SeDeM Expert System in liquisolid systems characterization. Pellets/admixtures were prepared with microcrystalline cellulose as carrier and crospovidone/silicon dioxide as coating agent. Ibuprofen solution in polyethylene glycol 400 was used as liquid phase. After comprehensive sample characterization, experimentally obtained parameters were mathematically transformed and evaluated in the SeDeM Expert System framework. Pellets exhibited low aspect ratio and excellent flowability, despite liquid load up to 52.2%. The investigated liquisolid admixtures exhibited good flowability and faster drug dissolution than pellets. Single pellet crushing test results exhibited strong correlation with compact indentation hardness and may be used as indentation hardness predictor. SeDeM Expert System provides useful insight into liquisolid system processability and comparative evaluation and it may facilitate final solid dosage form development.