Improving the solubility of nilotinib through novel spray-dried solid dispersions

The Optimization of Pair Distribution Functions for the Evaluation of the Degree of Disorder and Physical Stability in Amorphous Solids

The amorphous form of poorly soluble drugs is physically unstable and prone to crystallization, resulting in decreased solubility and bioavailability. However, the conventional accelerated stability test for amorphous drugs is time-consuming and inaccurate. Therefore, there is an urgent need to develop rapid and accurate stability assessment technology. This study used the antitumor drug nilotinib free base as a model drug. The degree of disorder and physical stability in the amorphous form was assessed by applying the pair distribution function (PDF) and principal component analysis (PCA) methods based on powder X-ray diffraction (PXRD) data. Specifically, the assessment conditions, such as the PDF interatomic distance range, PXRD detector type, and PXRD diffraction angle range were also optimized. The results showed that more reliable PCA data could be obtained when the PDF interatomic distance range was 0-15 Å. When the PXRD detector was a semiconductor-type detector, the PDF data obtained were more accurate than other detectors. When the PXRD diffraction angle range was 5-40°, the intermolecular arrangement of the amorphous drugs could be accurately predicted. Finally, the accelerated stability test also showed that under the above-optimized conditions, this method could accurately and rapidly assess the degree of disorder and physical stability in the amorphous form of drugs, which has obvious advantages compared with the accelerated stability test.

An Investigation of the Impact of Precipitation Temperature and Filter Cake Thickness on the Physical Stability of Amorphous Solids: A Case Study

The purpose of this study was to resolve the issue of physical instability in amorphous solid drugs, which can result in unwanted crystallization, affecting solubility and dissolution rates. The focus was on precipitating physically stable amorphous forms of the nilotinib free base, an anticancer drug, by monitoring preparation conditions such as precipitation temperature and filter cake thickness. A comprehensive set of characterization techniques, including powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and focused beam reflectance measurement (FBRM), were used. These were supplemented by advanced data analysis methods that incorporated pair distribution function (PDF), reduced crystallization temperature (Rc), and principal component analysis (PCA) to evaluate the physical stability of the amorphous samples. Results emphasized that optimal physical stability was achieved when amorphous solids were prepared at a precipitation temperature of 10 °C and a filter cake thickness of 4 cm. Moreover, the integration of PDF analysis with Rc values was confirmed as an innovative approach for assessing physical stability, thus offering enhanced efficiency and accuracy over conventional accelerated stability testing methods.

Enhanced biopharmaceutical performance of brick dust molecule nilotinib via stabilized amorphous nanosuspension using a facile acid-base neutralization approach

"Brick dust" compounds have high lattice energy as manifested by the poor aqueous solubility and suboptimal bioavailability. Nilotinib being a weakly basic brick dust molecule exhibits erratic and limited absorption during gastrointestinal transit, attributed to pre-absorptive factors like pH-dependent solubility, poor dissolution kinetics, and post-absorptive factors including P-gp-mediated drug efflux. In our study, these problems are addressed holistically by the successful fabrication of amorphous nanosuspension by an acid-base neutralization approach. The nanosuspension was obtained via rapid precipitation of nilotinib in an amorphous form and the generated in situ sodium chloride salt assisted in stabilizing the drug-loaded nanosuspension in a cage of salt and micellar stabilizer. Soluplus® and hypromellose acetate succinate (HPMCAS) were employed as a novel combination of stabilizers. Systematic optimization was carried out by employing the I-optimal method using Design Expert® software with a concentration of HPMCAS and Soluplus® as independent variables and evaluating them for responses viz particle size, polydispersity index (PDI), and zeta potential. The resultant nanosuspension showed a mean particle size of 130.5 ± 1.22 nm with a PDI value of 0.27 ± 0.01, and a zeta potential of - 5.21 ± 0.91 mV. The nanosuspension was further characterized for morphology, dissolution, and in vivo pharmacokinetics study. X-ray powder diffraction study of the nano-formulation displayed a halo pattern revealing the amorphous form. Stability studies showed that the nanosuspension remained stable at 40 °C ± 2 °C and 75% RH ± 5% RH for a period of three months. In vitro drug release and solubility study showed threefold and 36-fold enhancement in dissolution and solubility of the nanosuspension. Furthermore, an in vivo pharmacokinetic study in Sprague-Dawley rats following oral administration displayed a 1.46-fold enhancement in the relative bioavailability of the nanosuspension in contrast to neat nilotinib.

Amorphous Solid Dispersion as Drug Delivery Vehicles in Cancer

Cancer treatment has improved over the past decades, but a major challenge lies in drug formulation, specifically for oral administration. Most anticancer drugs have poor water solubility which can affect their bioavailability. This causes suboptimal pharmacokinetic performance, resulting in limited efficacy and safety when administered orally. As a result, it is essential to develop a strategy to modify the solubility of anticancer drugs in oral formulations to improve their efficacy and safety. A promising approach that can be implemented is amorphous solid dispersion (ASD) which can enhance the aqueous solubility and bioavailability of poorly water-soluble drugs. The addition of a polymer can cause stability in the formulations and maintain a high supersaturation in bulk medium. Therefore, this study aimed to summarize and elucidate the mechanisms and impact of an amorphous solid dispersion system on cancer therapy. To gather relevant information, a comprehensive search was conducted using keywords such as "anticancer drug" and "amorphous solid dispersion" in the PubMed, Scopus, and Google Scholar databases. The review provides an overview and discussion of the issues related to the ASD system used to improve the bioavailability of anticancer drugs based on molecular pharmaceutics. A thorough understanding of anticancer drugs in this system at a molecular level is imperative for the rational design of the products.

Advancement in Solubilization Approaches: A Step towards Bioavailability Enhancement of Poorly Soluble Drugs

A drug's aqueous solubility is defined as the ability to dissolve in a particular solvent, and it is currently a major hurdle in bringing new drug molecules to the market. According to some estimates, up to 40% of commercialized products and 70-90% of drug candidates in the development stage are poorly soluble, which results in low bioavailability, diminished therapeutic effects, and dosage escalation. Because of this, solubility must be taken into consideration when developing and fabricating pharmaceutical products. To date, a number of approaches have been investigated to address the problem of poor solubility. This review article attempts to summarize several conventional methods utilized to increase the solubility of poorly soluble drugs. These methods include the principles of physical and chemical approaches such as particle size reduction, solid dispersion, supercritical fluid technology, cryogenic technology, inclusion complex formation techniques, and floating granules. It includes structural modification (i.e., prodrug, salt formation, co-crystallization, use of co-solvents, hydrotrophy, polymorphs, amorphous solid dispersions, and pH variation). Various nanotechnological approaches such as liposomes, nanoparticles, dendrimers, micelles, metal organic frameworks, nanogels, nanoemulsions, nanosuspension, carbon nanotubes, and so forth have also been widely investigated for solubility enhancement. All these approaches have brought forward the enhancement of the bioavailability of orally administered drugs by improving the solubility of poorly water-soluble drugs. However, the solubility issues have not been completely resolved, owing to several challenges associated with current approaches, such as reproducibility in large scale production. Considering that there is no universal approach for solving solubility issues, more research is needed to simplify the existing technologies, which could increase the number of commercially available products employing these techniques.

Serum and lymph pharmacokinetics of nilotinib delivered by yeast glucan particles per os

Nilotinib is a selective tyrosine-kinase inhibitor approved for the treatment of chronic myeloid leukemia. It is poorly soluble in aqueous media and has a low oral bioavailability. Nilotinib encapsulation into yeast glucan particles (GPs) was investigated in this work as a means of increasing bioavailability. The amorphization of nilotinib in GPs resulted in an increased dissolution rate, which was confirmed by in vitro experiments using biorelevant dissolution media. Simultaneously, GPs containing nilotinib were effectively taken up by macrophages, which was quantified in vitro on cell cultures. The overall oral bioavailability in a rat model was approximately 39 % for nilotinib delivered in a reference formulation (Tasigna) and was almost doubled when delivered in GPs. The contribution of glucan particles to the lymphatic transport of nilotinib was quantified. When delivered by GPs, cumulative nilotinib absorption via the lymphatic system increased by a factor of 10.8 compared to the reference, but still represented arelative bioavailability of only 1.12 %. The cumulative uptake of GPs in the lymph was found to be 0.54 mg after a single dose of 50 mg. Yeast glucan particles can therefore serve as a drug delivery vehicle with a dual function: dissolution rate enhancement by amorphization, and, to asmaller extent, lymphatic delivery due to macrophage uptake.

Tyrosine kinase inhibitors as next generation oncological therapeutics: Current strategies, limitations and future perspectives

Protein kinases, a class of enzymes that govern various biological phenomena at a cellular level, are responsible for signal transduction in cells that regulate cellular proliferation, differentiation, and growth. Protein kinase enzyme mutation results in abnormal cell division leading to a pathological condition like cancer. Tyrosine kinase (TK) inhibitors, which helps as a potential drug candidate for the treatment of cancer, are continuously being developed. Majority of these drug candidates are being administered as conventional oral dosage form, which provides limited safety and efficacy due to non-specific delivery and uncontrolled biodistribution resulting into the adverse effects. A controlled drug delivery approach for the delivery of TK inhibitors may be a potential strategy with significant safety and efficacy profile. Novel drug delivery strategies provide target-specific drug delivery, improved pharmacokinetic behaviour, and sustained release leading to lower doses and dosing frequency with significantly reduced side effects. Along with basic aspects of tyrosine kinase, this review discusses various aspects related to the application of tyrosine kinase inhibitors in clinical oncological setting. Furthermore, the limitations/challenges and formulation advancements related to this class of candidates particularly for cancer management have been reviewed. It is expected that innovations in drug delivery approaches for TK inhibitors using novel techniques will surely provide a new insights for improved cancer treatment and patients' life quality.

Potential of solid dispersions to enhance solubility, bioavailability, and therapeutic efficacy of poorly water-soluble drugs: newer formulation techniques, current marketed scenario and patents

In the last few decades, solid dispersion (SD) technology had been studied as an approach to produce an amorphous carrier to enhance the solubility, dissolution rate, and bioavailability of poorly water-soluble drugs. The use of suitable carrier and methodology in the preparation of SDs play a significant role in the biological behavior of the SDs. SDs have been prepared using a variety of pharmaceutically acceptable polymers utilizing various novel technologies. In the recent years, much attention has been paid toward the use of novel carriers and methodologies in exploring novel types of SDs to enhance therapeutic efficacy and bioavailability. The use of novel carriers and methodologies would be very beneficial for formulation scientists to develop some SDs-based formulations for their commercial use and clinical applications. In the present review, current literature of novel methodologies for SD preparation to enhance the dissolution rate, solubility, therapeutic efficacy, and bioavailability of poorly water-soluble drugs has been summarized and analyzed. Further, the current status of SDs, patent status, and future prospects have also been discussed.

The Role of Functional Excipients in Solid Oral Dosage Forms to Overcome Poor Drug Dissolution and Bioavailability

Many active pharmaceutical ingredients (APIs) exhibit poor solubility and low dissolution rates in aqueous environments such as the luminal fluids of the gastrointestinal tract. The oral bioavailability of these compounds is usually very low as a result of their poor solubility properties. In order to improve the bioavailability of these poorly soluble drugs, formulation strategies have been applied as a means to improve their aqueous solubility and dissolution rates. With respect to formulation approaches, excipients can be incorporated in the formulation to assist in the dissolution process of the drug, or specialized dosage forms can be formulated that improve dissolution rate through various mechanisms. This paper provides an overview of selected excipients (e.g., alkalinizing agents, surfactants and sugars) that can be used in formulations to increase the dissolution rate as well as specialized dosage forms such as self-emulsifying delivery systems and formulation techniques such as inclusion complexes and solid dispersions. These formulation approaches are discussed with available examples with specific reference to positive outcomes in terms of drug solubility and bioavailability enhancement.

Preparation and optimization of nilotinib self-micro-emulsifying drug delivery systems to enhance oral bioavailability

Objective: The objective of the current research was to prepare self-micro-emulsifying drug delivery systems (SMEDDS) for BCS class II drug, nilotinib to enhance its oral bioavailability.Methodology: Different types of excipients like oil, surfactant, and co-surfactant were evaluated for drug solubility. Among the screened excipients, Capryol 90, Transcutol HP, and Tween 80 were selected as oil, co-surfactant, and surfactant, respectively, to construct a ternary phase diagram to identify a homogenous mixture. Characterization performed for the prepared SMEDDS for its particle size/droplet size, emulsification time, phase separation, droplet morphology, in vitro drug release, and oral bioavailability.Results: Prepared SMEDDS showed the highest of 87% drug release in in vitro drug release experiment. SMEDDS drug release was superior over suspension formulation, which could be attributed to oil/surfactant ratios and particle size of the SMEDDS. The acquired pharmacokinetic parameters indicate that twofold increase in systemic exposure of SMEDDS compared with nilotinib suspension formulation. A similar twofold increase in relative oral bioavailability was also observed when compared SMEDDS formulation with suspension formulation. Delayed T_max (time to reach peak plasma concentrations) was observed with SMEDDS over suspension formulation, which was evident by slow rate of absorption of nilotinib from SMEDDS.Conclusion: This research demonstrated that SMEDDS could be an effective approach to improve solubility and oral bioavailability for the BCS class II poorly soluble nilotinib.

An overview of techniques for multifold enhancement in solubility of poorly soluble drugs

Poor water solubility of newly discovered compounds has become the most common challenge in the drug development process. Indeed, poor solubility is considered as the root cause of failure of drug during drug development phases. Moreover, it has also been reported to be the main reason for bioavailability issues such as poor, inconsistent, incomplete and highly variable bioavailability of the marketed products. As per an estimate, approximately 90% of drug molecules suffer with poor water solubility at early stage and approximately 40% of the marketed drugs have bioavailability problems mainly due to poor water solubility. Solubility enhancement of the newly discovered compounds is primary research area for the pharmaceutical industries and research institutions. The conventional techniques to improve aqueous solubility of drugs employ salt formation, prodrug formation, co-crystallization, complexation, amorphous solid dispersion and use of co-solvent, surfactants or hydrotropic agents. Current advancement in the science and technology has enabled the use of relatively new techniques under the umbrella of nanotechnology. These include the development of nanocrystals, nanosuspensions, nanoemulsions, microemulsions, liposomes and nanoparticles to enhance the solubility. This review focuses on the conventional and current approaches of multifold enhancement in the solubility of poorly soluble marketed drugs, including newly discovered compounds.

Harnessing the therapeutic potential of anticancer drugs through amorphous solid dispersions

The treatment of cancer is still a major challenge. But tremendous progress in anticancer drug discovery and development has occurred in the last few decades. However, this progress has resulted in few effective oncology products due to challenges associated with anticancer drug delivery. Oral administration is the most preferred route for anticancer drug delivery, but the majority of anticancer drugs currently in product pipelines and the majority of those that have been commercially approved have inherently poor water solubility, and this cannot be mitigated without compromising their potency and stability. The poor water solubility of anticancer drugs, in conjunction with other factors, leads to suboptimal pharmacokinetic performance. Thus, these drugs have limited efficacy and safety when administered orally. The amorphous solid dispersion (ASD) is a promising formulation technology that primarily enhances the aqueous solubility of poorly water-soluble drugs. In this review, we discuss the challenges associated with the oral administration of anticancer drugs and the use of ASD technology in alleviating these challenges. We emphasize the ability of ASDs to improve not only the pharmacokinetics of poorly water-soluble anticancer drugs, but also their efficacy and safety. The goal of this paper is to rationalize the application of ASD technology in the formulation of anticancer drugs, thereby creating superior oncology products that lead to improved therapeutic outcomes.

Overview of the Manufacturing Methods of Solid Dispersion Technology for Improving the Solubility of Poorly Water-Soluble Drugs and Application to Anticancer Drugs

Approximately 40% of new chemical entities (NCEs), including anticancer drugs, have been reported as poorly water-soluble compounds. Anticancer drugs are classified into biologic drugs (monoclonal antibodies) and small molecule drugs (nonbiologic anticancer drugs) based on effectiveness and safety profile. Biologic drugs are administered by intravenous (IV) injection due to their large molecular weight, while small molecule drugs are preferentially administered by gastrointestinal route. Even though IV injection is the fastest route of administration and ensures complete bioavailability, this route of administration causes patient inconvenience to visit a hospital for anticancer treatments. In addition, IV administration can cause several side effects such as severe hypersensitivity, myelosuppression, neutropenia, and neurotoxicity. Oral administration is the preferred route for drug delivery due to several advantages such as low cost, pain avoidance, and safety. The main problem of NCEs is a limited aqueous solubility, resulting in poor absorption and low bioavailability. Therefore, improving oral bioavailability of poorly water-soluble drugs is a great challenge in the development of pharmaceutical dosage forms. Several methods such as solid dispersion, complexation, lipid-based systems, micronization, nanonization, and co-crystals were developed to improve the solubility of hydrophobic drugs. Recently, solid dispersion is one of the most widely used and successful techniques in formulation development. This review mainly discusses classification, methods for preparation of solid dispersions, and use of solid dispersion for improving solubility of poorly soluble anticancer drugs.

Applying Supercritical Fluid Technology to Prepare Ibuprofen Solid Dispersions with Improved Oral Bioavailability

In this study, supercritical fluid (SCF) technology was applied to prepare reliable solid dispersions of pharmaceutical compounds with limited bioavailability using ibuprofen (IBU) as a model compound. Solid-state characterization of the dispersions was conducted by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The PXRD and DSC results suggested that the amorphous form of IBU was maintained in the solid dispersions. Furthermore, in vitro dissolution and in vivo pharmacokinetic (PK) studies in rats were also performed. The dissolution performance of the SCF-prepared IBU dispersions was significantly improved compared to that of the physical mixtures of crystalline IBU and a polymer. In addition, the PK results revealed that the SCF-prepared IBU dispersions produced remarkably high blood drug concentrations (both the AUC and C_max) and a rapid absorption rate (T_max). Finally, molecular modeling was used to evaluate the binding energy of interactions between IBU and the polymers. The negative binding energy suggests a relatively stable system. Hence, SCF technology can be used as a very effective approach to prepare IBU solid dispersions with good physical stability and enhanced in vitro and in vivo performance.

Effect of Shape on Mesoporous Silica Nanoparticles for Oral Delivery of Indomethacin

The use of mesoporous silica nanoparticles (MSNs) in the field of oral drug delivery has recently attracted greater attention. However, there is still limited knowledge about how the shape of MSNs affects drug delivery capacity. In our study, we fabricated mesoporous silica nanorods (MSNRs) to study the shape effects of MSNs on oral delivery. MSNRs were characterized by transmission electron microscopy (TEM), nitrogen adsorption/desorption, Fourier transform infrared spectroscopy (FTIR), and small-angle X-ray diffraction (small-angle XRD). Indomethacin (IMC), a non-steroidal anti-inflammatory agent, was loaded into MSNRs as model drug, and the drug-loaded MSNRs resulted in an excellent dissolution-enhancing effect. The cytotoxicity and in vivo pharmacokinetic studies indicated that MSNRs can be applied as a safe and efficient candidate for the delivery of insoluble drugs. The use of MSNs with a rod-like shape, as a drug delivery carrier, will extend the pharmaceutical applications of silica materials.

Solubility and bioavailability improvement of pazopanib hydrochloride

The anti-cancer drug pazopanib hydrochloride (PZH) has a very low aqueous solubility and a variable oral bioavailability. A new pharmaceutical formulation with an improved solubility may enhance the bioavailability and reduce the variability. A broad selection of polymer excipients was tested for their compatibility and solubilizing properties by conventional microscopic, thermal and spectrometric techniques. A wet milling and mixing technique was used to produce homogenous powder mixtures. The dissolution properties of the formulation were tested by a pH-switch dissolution model. The final formulation was tested in vivo in cancer patient following a dose escalation design. Of the tested mixture formulations, the one containing the co-block polymer Soluplus® in a 8:1 ratio with PZH performed best in terms of in vitro dissolution properties. The in vivo results indicated that 300 mg of the developed formulation yields similar exposure and a lower variability (379 μg/mL∗h (36.7% CV)) than previously reported values for the standard PZH formulation (Votrient®) at the approved dose of 800 mg. Furthermore, the expected plasma-C_through levels (27.2 μg/mL) exceeds the defined therapeutic efficacy threshold of 20 μg/mL.