Dissolution enhancement of tadalafil by liquisolid technique

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.

Enhancement of ketoprofen dissolution rate by the liquisolid technique: optimization and in vitro and in vivo investigations

The objective of the current study is to evaluate the prospective of liquisolid formulation to improve the dissolution rate of ketoprofen and thereby the bioavailability. Different batches of liquisolid were prepared using polyethylene glycol 200 as a solvent, microcrystalline cellulose, and aerosil 200 as carrier and coating material, respectively. Central composite design (3²) was utilized to examine the effects of independent variables (load factor and excipient ratio) on dependent variables (solubility and % in vitro drug release). Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy techniques were employed for characterization of optimized batch (LS-10) of liquisolid formulation. The half-maximal inhibitory concentration (IC₅₀) values for in vitro anti-inflammatory activity for liquisolid formulation exhibited a higher anti-inflammatory effect than ketoprofen and physical mixture. The statistical analysis of in vivo (anti-inflammatory and analgesic) activities data demonstrated that the test (optimized formulation) treatment group resulted in quick pharmacological response in Wistar rats and Albino mice when compared with standard (pure drug) and control treatment groups. The results obtained in the present study illustrated that the liquisolid formulation could be a propitious approach to increase the bioavailability of ketoprofen and could be used in oral therapy.

Combining Liquisolid and Co-grinding Techniques to Enhance the Dissolution Rate of Celecoxib

Purpose

The classic liquisolid technique is used to enhance the dissolution rate of poorly water-soluble drugs, but in some cases, it is impossible to reach the desired dissolution rate using this technique alone. Therefore, a novel approach using a combination of ball milling and liquisolid technology was investigated to improve the dissolution rate for celecoxib.

Methods

First, celecoxib was dispersed in a liquid vehicle (PEG 200), then ground in a ball mill for 3 h. Other excipients, including PVP, microcrystalline cellulose as the carrier powder, and silica as the coating material, were added to the mortar. Dissolution testing was carried out in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF) media. The effects of aging on the hardness and dissolution profile were also studied. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) was used to identify changes in the crystallinity or complex formation.

Results

The novel formulations showed a higher dissolution rate than the conventional tablet or classic liquisolid formulations. Aging did not affect the hardness and dissolution profiles of the liquisolid compacts. The DSC and XRD results suggested that the enhanced dissolution rate is not caused by the formation of any complexes and reduction in crystallinity degree may contribute to the dissolution enhancement. The enhanced dissolution rate is attributed to the elevated specific surface area of the drug in the liquisolid state.

Conclusion

The results showed that liquisolid technology combined with ball milling is an efficient tool for enhancing the dissolution of poorly water-soluble drugs.

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.

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

Liquisolid technology, as a promising approach for bioavailability enhancement, has received increasing attention in recent years. However, literature reports addressing the challenges for its industrial application, particularly those related to compaction behavior of liquisolid systems, are scarce. The aim of this study was to investigate the influence of process parameters and formulation variables on the flowability, wetting, and compaction properties of the liquisolid systems prepared in a fluid bed processor. The experiments with microcrystalline cellulose, as a carrier, were performed according to 2³ full factorial design. The effects of liquid content, spray air pressure, and liquid feed rate on the properties of liquisolid systems were investigated. Liquisolid admixtures with microcrystalline cellulose were compared with those prepared with novel carriers, Fujicalin^® and Neusilin^® US2. "Out-die" Heckel, modified Walker, and Kuentz-Leuenberger models were used to analyze the compressibility of liquisolid admixtures. The results obtained showed that an increase in liquid content (in the range of 10 to 15%) led to a decrease in flowability of liquisolid admixtures with microcrystalline cellulose, as well as more pronounced influence of spraying conditions. On the other hand, higher liquid content led to higher compressibility. Fujicalin^® and Neusilin^® US2 liquisolid admixtures were found to have superior flowability and compressibility in comparison with those with microcrystalline cellulose, despite the considerably higher liquid load (50-55% liquid content in Neusilin^® US2 compacts). Acceptable compactibility of the investigated liquisolid systems was observed. The fluid bed processor was shown to be suitable equipment for production of liquisolid systems, but with careful adjustment of process parameters.

Enhancing the Hypolipidemic Effect of Simvastatin in Poloxamer-Induced Hyperlipidemic Rats via Liquisolid Approach: Pharmacokinetic and Pharmacodynamic Evaluation

This study aimed to enhance the dissolution of simvastatin (SMV) through its formulation in liquisolid tablets (LSTs) to improve its bioavailability and hypolipidemic activity after oral administration. SMV-LSTs were optimized using Box-Behnken design to maximize the rate and extent of SMV dissolution. The optimized SMV-LST was evaluated for pharmacokinetic parameters and potential hypolipidemic activity on induced hyperlipidemic rats. The dissolution parameters revealed a shortening of mean dissolution time from 10.99 to 6.82 min, increasing of dissolution rate during the first 10 min from 1253.15 to 1667.31 μg/min, and enhancing of dissolution efficiency after 60 min from 71.92 to 86.93% for SMV-LSTs versus the commercial SMV tablets. The obtained data reflected an improvement in the relative bioavailability of SMV with 148.232% which was confirmed by the significant reduction of the levels of circulating total cholesterol, triglycerides that reached the normal level after 12 h. In particular, the optimized SMV-LSTs reduced serum low-density lipoproteins (LDL) by 44.6% which was significantly different from the commercial SMV tablets. In contrast, the level of serum high-density lipoprotein (HDL) was significantly augmented after 4 h in rats treated with the optimized SMV-LSTs by 47.6%. Finally, the optimized SMV-LSTs showed a significant lower atherosclerotic index value which could maximize its potential in decreasing the risk of coronary disease and atherosclerosis. Overall enhancement in pharmacokinetics and pharmacodynamics in comparison with the commercial tablets confers the potential of the liquisolid approach as a promising alternative for improved oral bioavailability, hypolipidemic, and cardioprotective effects of SMV. Graphical abstract.

Formulation and evaluation of liquisolid compacts of itraconazole to enhance its oral bioavailability

Aim: Formulate and evaluate liquisolid compacts of Itraconazole, a biopharmaceutical classification system class II drug, which has poor bioavailability. Materials & methods: PEG 600 was used as a nonvolatile solvent, Alfacel PH 200 as a carrier and Aerosil 200 as a coating material. The Itraconazole solution upon mixing with a carrier and coating material resulted in a dry powder, which was compressed into tablets. Results & conclusion: The optimized formulation exhibited a significantly higher drug dissolution (90.73% in 90 min) compared with conventional tablets and marketed capsules. The antifungal activity was retained in the formulation. Higher values of Cmax and AUC0-24 of the formulation compared with the plain drug indicated enhancement in oral bioavailability. The formulation was stable at room temperature as well as in accelerated conditions.

Preparation of Curcuma comosa tablets using liquisolid techniques: In vitro and in vivo evaluation

Curcuma comosa (C. comosa) is a Thai medicinal herb that provides numerous pharmacologic activities due to its estrogen-like action. This study aimed to investigate the use of liquisolid technique to prepare tablets containing oleoresin-like crude extract of C. comosa, and to improve the dissolution profiles of its major compounds, diarylheptanoids (DAs). Free flowing powders of C. comosa extract were obtained by adsorption onto solid carriers, microcrystalline cellulose, with colloidal silica as coating material. FTIR results ruled out possible interactions between C. comosa extract and excipients. The results indicated that all of liquisolid tablets met the USP requirements. The release of DAs were significantly increased through liquisolid formulations, compared to crude extract. By decreasing the ratio of carrier to coating from 20 to 10, an improvement in dissolution rate was observed. Addition of additives - namely polymer (polyvinyl pyrrolidone) and/or nonvolatile liquid (propylene glycol) affected tablet properties which involved longer disintegration time and lower DA dissolution. Optimized C. comosa liquisolid formulation was prepared in a carrier to coating ratio of 10 without additives. Stability studies showed that physical properties of liquisolid tablet were not affected by aging, but percent remaining and dissolution profiles of DAs were influenced by storage temperature. In vivo pharmacokinetic behavior of the optimized C. comosa liquisolid tablets was investigated following a single oral administration to rabbits. The results proved that the method used for preparation of liquisolid led to C. comosa tablets with low variation in content uniformity and tablet properties, as well as enhanced dissolution behavior.

Enhancement of ketoconazole dissolution rate by the liquisolid technique

The study was conducted to enhance the dissolution rate of ketoconazole (KCZ) (a poorly water-soluble drug) using the liquisolid technique. Microcrystalline cellulose, colloidal silica, PEG400 and polyvinyl pyrrolidone (PVP) were employed as a carrier, coating substance, nonvolatile solvent and additive in the KCZ liquisolid compact formulation, respectively. The drug-to-PEG400 and carrier-to-coating ratio variations, PVP concentration and aging effects on the in vitro release behavior were assessed. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) data revealed no alterations in the crystalline form of the drug and the KCZ-excipient interactions within the process. The load factor and the drug release rate were significantly enhanced compared to directly compressed tablets in the presence of the additive. Increasing the PEG400-to-drug ratio in liquid medications enhanced the dissolution rate remarkably. The dissolution profile and hardness of liquisolid compacts were not significantly altered by keeping the tablets at 40 °C and relative humidity of 75 % for 6 months. With the proposed modification of the liquisolid process, it is possible to obtain flowable, compactible liquisolid powders of high-dose poorly-water soluble drugs with an enhanced dissolution rate.

Development of a New Aprepitant Liquisolid Formulation with the Aid of Artificial Neural Networks and Genetic Programming

In the present study, liquisolid formulations were developed for improving dissolution profile of aprepitant (APT) in a solid dosage form. Experimental studies were complemented with artificial neural networks and genetic programming. Specifically, the type and concentration of liquid vehicle was evaluated through saturation-solubility studies, while the effect of the amount of viscosity increasing agent (HPMC), the type of wetting (Soluplus® vs. PVP) and solubilizing (Poloxamer®407 vs. Kolliphor®ELP) agents, and the ratio of solid coating (microcrystalline cellulose) to carrier (colloidal silicon dioxide) were evaluated based on in vitro drug release studies. The optimum liquisolid formulation exhibited improved dissolution characteristics compared to the marketed product Emend®. X-ray diffraction (XRD), scanning electron microscopy (SEM) and a novel method combining particle size analysis by dynamic light scattering (DLS) and HPLC, revealed that the increase in dissolution rate of APT in the optimum liquisolid formulation was due to the formation of stable APT nanocrystals. Differential scanning calorimetry (DSC) and attenuated total reflection FTIR spectroscopy (ATR-FTIR) revealed the presence of intermolecular interactions between APT and liquisolid formulation excipients. Multilinear regression analysis (MLR), artificial neural networks (ANNs), and genetic programming (GP) were used to correlate several formulation variables with dissolution profile parameters (Y _15min and Y _30min) using a full factorial experimental design. Results showed increased correlation efficacy for ANNs and GP (RMSE of 0.151 and 0.273, respectively) compared to MLR (RMSE = 0.413).

Liquisolid technique and its applications in pharmaceutics

Most of the newly developed drug candidates are lipophilic and poorly water-soluble. Enhancing the dissolution and bioavailability of these drugs is a major challenge for the pharmaceutical industry. Liquisolid technique, which is based on the conversion of the drug in liquid state into an apparently dry, non-adherent, free flowing and compressible powder, is a novel and advanced approach to tackle the issue. The objective of this article is to present an overview of liquisolid technique and summarize the progress of its applications in pharmaceutics. Low cost, simple processing and great potentials in industrial production are main advantages of this approach. In addition to the enhancement of dissolution rate of poorly water-soluble drugs, this technique is also a fairly new technique to effectively retard drug release. Furthermore, liquisolid technique has been investigated as a tool to minimize the effect of pH variation on drug release and as a promising alternative to conventional coating for the improvement of drug photostability in solid dosage forms. Overall, liquisolid technique is a newly developed and promising tool for enhancing drug dissolution and sustaining drug release, and its potential applications in pharmaceutics are still being broadened.