Evaluation of Spironolactone Solid Dispersions Prepared by Co-Spray Drying With Soluplus® and Polyvinylpyrrolidone and Influence of Tableting on Drug Release

Toltrazuril alkalizer-modifying solid dispersions against Toxoplasma gondii: A pharmacotechnical strategy to improve the efficacy of the drug

Toxoplasma gondii is a zoonotic protozoan that can parasitize nucleated cells of all warm-blooded animals, and seriously harm human and livestock. Toltrazuril (TOL) has insecticidal activity against parasites of the phylum Apicomplexan at multiple development stages, but the clinical application is limited by its poor water solubility. To improve the dissolution of TOL, nine ternary solid dispersions (SD) were prepared with PEG6000 as the carrier and various alkalizers as the pH modifier. Compared with the binary SD, all ternary SDs had improved TOL dissolution although dissolution rates differed. The complete dissolution was achieved for the Ca(OH)2-SD, associated with a gradual release of the alkalizer and adequate pH regulation of the microenvironment. DSC, PXRD and FTIR analyses indicated that TOL in the Ca(OH)2-SD was present in an amorphous form and had a strong hydrogen bond with Ca(OH)2. Within the drug concentration of 100 μg/mL, Ca(OH)2-SD was proved to have no damage to host cells by in vitro cytotoxicity analysis, and its anti-T. gondii efficacy was significantly higher than that of TOL and binary SD. The in vivo efficacy of Ca(OH)2-SD against T. gondii in mice further confirmed that Ca(OH)2-SD could be used as a new strategy to prevent T. gondii from killing mice and treat toxoplasmosis. In conclusion, Ca(OH)2-SD is expected to eventually turn into a clinical candidate for toxoplasmosis treatment in the future.

Composites of N-butyl-N-methyl-1-phenylpyrrolo[1,2-a]pyrazine-3-carboxamide with Polymers: Effect of Crystallinity on Solubility and Stability

This work aimed to develop and characterize a water-soluble, high-release active pharmaceutical ingredient (API) composite based on the practically water-insoluble API N-butyl-N-methyl-1-phenylpyrrolo[1,2-a]pyrazine-3-carboxamide (GML-3), a substance with antidepressant and anxiolytic action. This allows to ensure the bioavailability of the medicinal product of combined action. Composites obtained by the method of creating amorphous solid dispersions, where polyvinylpyrrolidone (PVP) or Soluplus® was used as a polymer, were studied for crystallinity, stability and the release of API from the composite into purified water. The resulting differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD), and dissolution test data indicate that the resulting composites are amorphous at 1:15 API: polymer ratios for PVP and 1:5 for Soluplus®, which ensures the solubility of GML-3 in purified water and maintaining the supercritical state in solution.

Fabrication and characterization of anti-rosacea 3D nanofibrous customized sheet masks as a novel scaffold for repurposed use of spironolactone with pre-clinical studies

The repurposed oral use of spironolactone (SP) as an anti-rosacea drug faces many challenges that hinder its efficacy and compliance. In this study, a topically applied nanofibers (NFs) scaffold was evaluated as a promising nanocarrier that enhances SP activity and avoids the friction routine that exaggerates rosacea patients' inflamed, sensitive skin. SP-loaded poly-vinylpyrrolidone (40% PVP) nanofibers (SP-PVP NFs) were electrospun. Scanning electron microscopy showed that SP-PVP NFs have a smooth homogenous surface with a diameter of about 426.60 nm. Wettability, solid state, and mechanical properties of NFs were evaluated. Encapsulation efficiency and drug loading were 96.34% ± 1.20 and 11.89% ± 0.15, respectively. The in vitro release study showed a higher amount of SP released over pure SP with a controlled release pattern. Ex vivo results showed that the permeated amount of SP from SP-PVP NFs sheets was 4.1 times greater than that of pure SP gel. A higher percentage of SP was retained in different skin layers. Moreover, the in vivo anti-rosacea efficacy of SP-PVP NFs using croton oil challenge showed a significant reduction in erythema score compared to the pure SP. The stability and safety of NFs mats were proved, indicating that SP-PVP NFs are promising carriers of SP.

Amorphization of Drugs for Transdermal Delivery-a Recent Update

Amorphous solid dispersion is a popular formulation approach for orally administered poorly water-soluble drugs, especially for BCS class II. But oral delivery could not be an automatic choice for some drugs with high first-pass metabolism susceptibility. In such cases, transdermal delivery is considered an alternative if the drug is potent and the dose is less than 10 mg. Amorphization of drugs causes supersaturation and enhances the thermodynamic activity of the drugs. Hence, drug transport through the skin could be improved. The stabilization of amorphous system is a persistent challenge that restricts its application. A polymeric system, where amorphous drug is dispersed in a polymeric carrier, helps its stability. However, high excipient load often becomes problematic for the polymeric amorphous system. Coamorphous formulation is another approach, where one drug is mixed with another drug or low molecular weight compound, which stabilizes each other, restricts crystallization, and maintains a single-phase homogenous amorphous system. Prevention of recrystallization along with enhanced skin permeation has been observed by the transdermal coamorphous system. But scalable manufacturing methods, extensive stability study and in-depth in vivo evaluation are lacking. This review has critically studied the mechanistic aspects of amorphization and transdermal permeation by analyzing recent researches in this field to propose a future direction.

Study of Different Chitosan/Sodium Carboxymethyl Cellulose Proportions in the Development of Polyelectrolyte Complexes for the Sustained Release of Clarithromycin from Matrix Tablets

This study investigated the combination of different proportions of cationic chitosan and anionic carboxymethyl cellulose (CMC) for the development of polyelectrolyte complexes to be used as a carrier in a sustained-release system. Analysis via scanning electron microscopy (SEM) Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) confirmed ionic interactions occur between the chitosan and carboxymethyl cellulose chains, which increases drug entrapment. The results of the dissolution study in acetate buffer (pH 4.2) showed significant increases in the kinetic profiles of clarithromycin for low proportions of chitosan/carboxymethyl cellulose tablets, while the tablets containing only chitosan had high relaxation of chitosan chains and disintegrated rapidly. The Korsmeyer–Peppas kinetic model for the different interpolymer complexes demonstrated that the clarithromycin transport mechanism was controlled by Fickian diffusion. These results suggest that the matrix tablets with different proportions of chitosan/carboxymethyl cellulose enhanced the ionic interaction and enabled the prolonged release of clarithromycin.

Amorphous Salts Solid Dispersions of Celecoxib: Enhanced Biopharmaceutical Performance and Physical Stability

Numerous amorphous solid dispersion (ASD) formulations of celecoxib (CEL) have been attempted for enhancing the solubility, dissolution rate, and in vivo pharmacokinetics via high drug loading, polymer combination, or by surfactant addition. However, physical stability for long-term shelf life and desired in vivo pharmacokinetics remains elusive. Therefore, newer formulation strategies are always warranted to address poor aqueous solubility and oral bioavailability with extended shelf life. The present investigation elaborates a combined strategy of amorphization and salt formation for CEL, providing the benefits of enhanced solubility, dissolution rate, in vivo pharmacokinetics, and physical stability. We generated amorphous salts solid dispersion (ASSD) formulations of CEL via an in situ acid-base reaction involving counterions (Na⁺ and K⁺) and a polymer (Soluplus) using the spray-drying technique. The generated CEL-Na and CEL-K salts were homogeneously and molecularly dispersed in the matrix of Soluplus polymer. The characterization of generated ASSDs by differential scanning calorimetry revealed a much higher glass-transition temperature (T_g) than the pure amorphous CEL, confirming the salt formation of CEL in solid dispersions. The micro-Raman and proton nuclear magnetic resonance spectroscopy further confirmed the formation of salt at the -S═O position in the CEL molecules. CEL-Na-Soluplus ASSD exhibited a synergistic enhancement in the aqueous solubility (332.82-fold) and in vivo pharmacokinetics (9.83-fold enhancement in the blood plasma concentration) than the crystalline CEL. Furthermore, ASSD formulations were physically stable for nearly 1 year (352 days) in long-term stability studies at ambient conditions. Hence, we concluded that the ASSD is a promising strategy for CEL in improving the physicochemical properties and biopharmaceutical performance.

The use of polymer blends to improve stability and performance of electrospun solid dispersions: The role of miscibility and phase separation

Solid dispersion-based nanofiber formulations of poorly soluble drugs prepared by electrospinning (ES) with a water-soluble polymer, can offer significant improvements in drug dissolution for oral drug administration. However, when hygroscopic polymers, such as polyvinylpyrrolidone (PVP) are used, environmental moisture sorption can lead to poor physical stability on storage. This study investigated the use of polymer blends to modify PVP-based ES formulations of a model poorly soluble drug, fenofibrate (FF), to improve its physical stability without compromising dissolution enhancement. FF-PVP ES dispersions demonstrated clear dissolution enhancement, but poor storage stability against high humidity. Polymer blends of PVP with Eudragit E, Soluplus and hypromellose acetate succinate (HPMCAS), were selected because of the low intrinsic moisture sorption of these polymers. The drug-polymer and polymer-polymer miscibility study revealed that FF was more miscible with Eudragit E and Soluplus than with PVP and HPMCAS, and that PVP was more miscible with HPMCAS than Eudragit E and Soluplus. This led to different configurations of phase separation in the placebo and drug-loaded fibres. The in vitro drug release data confirmed that the use of PVP-Eudragit E retained the dissolution enhancement of the PVP formulation, whereas PVP-Soluplus reduced the drug release rate in comparison to FF-PVP formulations. The moisture sorption results confirmed that moisture uptake by the polymer blends was reduced, but formulation deformation occurred to phase-separated blend formulations. The data revealed the importance of miscibility and phase separation in understanding the physical stability of the ES fibre mats. The findings provide insight into the design of formulations that can provide dissolution enhancement balanced with improved storage stability.

Spray Drying for Direct Compression of Pharmaceuticals

Tableting by direct compression (DC) is one of the simplest and most cost-effective drug manufacturing approaches. However, most active pharmaceutical ingredients (APIs) and excipients lack the compression and flow properties required to meet the needs of high-speed industrial tablet presses. Therefore, the majority of DC APIs and excipients are modified via processing/co-processing particle engineering techniques to boost their properties. Spray drying is one of the most commonly employed techniques to prepare DC grades of APIs and excipients with prominent advantages. This review aims to present an overview of the commercially marketed and investigationally-prepared DC APIs and excipients produced by spray drying.

Comparison of Amorphous Solid Dispersions of Spironolactone Prepared by Spray Drying and Electrospinning: The Influence of the Preparation Method on the Dissolution Properties

This research aimed to compare two solvent-based methods for the preparation of amorphous solid dispersions (ASDs) made up of poorly soluble spironolactone and poly(vinylpyrrolidone-co-vinyl acetate). The same apparatus was used to produce, in continuous mode, drug-loaded electrospun (ES) and spray-dried (SD) materials from dichloromethane and ethanol-containing solutions. The main differences between the two preparation methods were the concentration of the solution and application of high voltage. During electrospinning, a solution with a higher concentration and high voltage was used to form a fibrous product. In contrast, a dilute solution and no electrostatic force were applied during spray drying. Both ASD products showed an amorphous structure according to differential scanning calorimetry and X-ray powder diffraction results. However, the dissolution of the SD sample was not complete, while the ES sample exhibited close to 100% dissolution. The polarized microscopy images and Raman microscopy mapping of the samples highlighted that the SD particles contained crystalline traces, which can initiate precipitation during dissolution. Investigation of the dissolution media with a borescope made the precipitated particles visible while Raman spectroscopy measurements confirmed the appearance of the crystalline active pharmaceutical ingredient. To explain the micro-morphological differences, the shape and size of the prepared samples, the evaporation rate of residual solvents, and the influence of the electrostatic field during the preparation of ASDs had to be considered. This study demonstrated that the investigated factors have a great influence on the dissolution of the ASDs. Consequently, it is worth focusing on the selection of the appropriate ASD preparation method to avoid the deterioration of dissolution properties due to the presence of crystalline traces.

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.

Application of HPMC HME polymer as hot melt extrusion carrier in carbamazepine solid dispersion

AIM

This work is to investigate the application characteristics of a new hot melt extrusion (HME) polymer (HME-grade hydroxypropyl methylcellulose, namely HPMC HME 15LV) in solid dispersion by HME.

METHODS

Carbamazepine (CBZ) was chosen as the model drug. And two types of solid dispersion system was prepared by HME, that is, single carrier system which was composed of PVP VA64(VA64) or Soluplus (SOL), and binary carrier which was composed of HPMC HME 15LV and SOL. Phase analysis of the extrudates were characterized by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). The dissolution, moisture absorption and thermal stability CBZ solid dispersion (CBZ-SD) were also investigated. In addition, the mechanism that affects the capsule dissolution was evaluated by the viscosity test and infiltration capability test.

RESULTS

CBZ-SD was prepared by HME. DSC and PXRD results indicated that CBZ was amorphous in all solid dispersions. Unlike CBZ-SD powder with high dissolution, CBZ-SD capsules showed the variable gelatinization phenomenon during dissolution and different dissolution behaviors, which can be interpreted by the viscosity test and infiltration capacity test. Furthermore, compared with single carrier system, CBZ-SD made by binary carrier exhibited lower moisture absorption and better thermal stability, which is benefit to the long-term stability of CBZ-SD.

CONCLUSION

HPMC HME 15LV, as a new HME carrier, has certain advantages in producing well CBZ-SD preparation. Its low viscosity can prevent the gelatinization phenomenon during capsule dissolution, as well as suitable T_g and low hygroscopicity were also benefit to the stability of CBZ-SD.

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.

Micellisation Mechanism and Behaviour of Soluplus®⁻Furosemide Micelles: Preformulation Studies of an Oral Nanocarrier-Based System

In this study, self-assembling Soluplus^® micelles were examined for inherent properties. Through calorimetric analysis, the critical micelle concentration (CMC) could be determined at 25 and 37 °C, and the influence of three media (Milli-Q water, phosphate-buffered saline (PBS) with a pH of 7.4 and 0.1 M HCl) on the lower critical solution temperature (LCST) was detected. Furthermore, the solubilisation of a poorly soluble drug, furosemide, into the Soluplus^® micelles was studied. The concentration-dependent properties of the micellar system were assessed through an examination of the micellar size, polydispersity, morphology, viscosity and solubilising properties, which were all found to be affected by the concentration, but temperature, pH and the composition of the test medium were also found to have an effect. Homogeneity in the estimated micellar size and morphology was shown for monophasic micelle dispersions in lower concentrations and with a shift towards more complex structures or aggregates in higher concentrations. The micelles were further investigated in terms of drug release and biocompatibility with mucus-producing HT29-MTX cells, where no biocompatibility issues were found. In this research, the implications for oral drug delivery are discussed and valuable preformulation information is provided on the micellar properties of a Soluplus^® drug system in a liquid or semi-solid form.