Cocrystal habit engineering to improve drug dissolution and alter derived powder properties

Targeted Oral Fixed-Dose Combination of Amphotericin B-Miltefosine for Visceral Leishmaniasis

The incidence of visceral leishmaniasis (VL) remains a significant health threat in endemic countries. Fixed-dose combination (FDC) of amphotericin B (AmB) and miltefosine (MLT) is a promising strategy for treating VL, but the parenteral administration of AmB leads to severe side effects, limiting its use in clinical practice. Here, we developed novel FDC granules combining AmB in the core with a MLT coating using wet granulation followed by the fluidized bed technology. The granules maintained the crystalline structure of AmB throughout manufacturing, achieving an AmB loading of ∼20%. The MLT coating layer effectively sustained AmB release from 3 to 24 h following Korsmeyer-Peppas kinetics. The formulation demonstrated remarkable stability, maintaining >90% drug content for over a year at both 4 °C and room temperature under desiccated conditions. In vivo efficacy studies in Leishmania infantum-infected hamsters showed 65-80% reduction in parasite burden in spleen and liver, respectively, suggesting potential as an oral alternative to current VL treatments. Uncoated and coated granules demonstrated comparable performance in key aspects, including in vivo efficacy and long-term stability.

New Perspectives for Antihypertensive Sartans as Components of Co-crystals and Co-amorphous Solids with Improved Properties and Multipurpose Activity

Sartans (angiotensin II receptor blockers, ARBs), drugs used in the treatment of hypertension, play a principal role in addressing the global health challenge of hypertension. In the past three years, their potential use has expanded to include the possibility of their application in the treatment of COVID-19 and neurodegenerative diseases (80 clinical studies worldwide). However, their therapeutic efficacy is limited by their poor solubility and bioavailability, prompting the need for innovative approaches to improve their pharmaceutical properties. This review discusses methods of co-crystallization and co-amorphization of sartans with nonpolymeric, low molecular, and stabilizing co-formers, as a promising strategy to synthesize new multipurpose drugs with enhanced pharmaceutical properties. The solid-state forms have demonstrated the potential to address the poor solubility limitations of conventional sartan formulations and offer new opportunities to develop dual-active drugs with broader therapeutic applications. The review includes an in-depth analysis of the co-crystal and co-amorphous forms of sartans, including their properties, possible applications, and the impact of synthetic methods on their pharmacokinetic properties. By shedding light on the solid forms of sartans, this article provides valuable insights into their potential as improved drug formulations. Moreover, this review may serve as a valuable resource for designing similar solid forms of sartans and other drugs, fostering further advances in pharmaceutical research and drug development.

Formation of Hemihydrate Crystal form Overcomes Milling Issue Induced by Exposed Functional Groups on Cleavage Plane for a Y5 Receptor Antagonist of Neuropeptide Y

This study aimed to investigate the crystal forms of an originally designed Y5 receptor antagonist of neuropeptide Y. Polymorphic screening was performed via solvent evaporation and slurry conversion using various solvents. The obtained crystal forms α, β, and γ were characterized by X-ray powder diffraction analysis. Thermal analysis determined that forms α, β, and γ were hemihydrate, metastable and stable forms, respectively; the hemihydrate and the stable forms were candidates. To arrange the particle size, forms α and γ were subjected to jet milling. However, form γ could not be milled because of powder stiction to the apparatus, whereas form α could be. To investigate this mechanism, single-crystal X-ray diffraction analysis was performed. The crystal structure of form γ was characterized by two-dimensional hydrogen bonding between neighboring molecules. This revealed that the functional groups forming hydrogen bonds were exposed on the cleavage plane of form γ. The three-dimensional hydrogen-bonding network with water stabilized the hemihydrate form, α. These results indicate that the hydrogen bondable groups exposed on the cleavage plane of form γ should result in stiction of the powder and adherence to the apparatus. It was concluded that crystal conversion is a method to overcome the milling issue.

Cylindrical granules in the development of mesalazine solid formulations (Ⅰ): Physical properties, compression behaviors, and tableting performances

Cylindrical granules have been employed in the pharmaceutical industry. However, to our knowledge, the study on the compressibility and tabletability of cylindrical granules has not been reported. This study aimed to explore the effects of the physical properties of cylindrical granules on the compression behaviors and the tableting performances, with mesalazine (MSZ) as a model drug. First, the six formulations of MSZ cylindrical granules were extruded by changing the ethanol proportion in the binder. Then, the physical characteristics of MSZ cylindrical granules were systematically studied. Subsequently, the compressibility and tabletability were evaluated using different mathematic models. It was worth noting that highly porous cylindrical granules possessed favorable compressibility and good tabletability due to the increased pore volume, reduced density, and decreased fracture forces. Finally, dissolution tests were conducted and highly porous granules showed higher dissolution rates than the less porous ones, but an opposite trend was observed for the corresponding tablets. This study proved the importance of physical properties in the tableting process of cylindrical granules and provided strategies to improve their compressibility and tabletability.

Continuous Manufacturing of Cocrystals Using 3D-Printed Microfluidic Chips Coupled with Spray Coating

Using cocrystals has emerged as a promising strategy to improve the physicochemical properties of active pharmaceutical ingredients (APIs) by forming a new crystalline phase from two or more components. Particle size and morphology control are key quality attributes for cocrystal medicinal products. The needle-shaped morphology is often considered high-risk and complex in the manufacture of solid dosage forms. Cocrystal particle engineering requires advanced methodologies to ensure high-purity cocrystals with improved solubility and bioavailability and with optimal crystal habit for industrial manufacturing. In this study, 3D-printed microfluidic chips were used to control the cocrystal habit and polymorphism of the sulfadimidine (SDM): 4-aminosalicylic acid (4ASA) cocrystal. The addition of PVP in the aqueous phase during mixing resulted in a high-purity cocrystal (with no traces of the individual components), while it also inhibited the growth of needle-shaped crystals. When mixtures were prepared at the macroscale, PVP was not able to control the crystal habit and impurities of individual mixture components remained, indicating that the microfluidic device allowed for a more homogenous and rapid mixing process controlled by the flow rate and the high surface-to-volume ratios of the microchannels. Continuous manufacturing of SDM:4ASA cocrystals coated on beads was successfully implemented when the microfluidic chip was connected in line to a fluidized bed, allowing cocrystal formulation generation by mixing, coating, and drying in a single step.

Engineering of 3D printed personalized polypills for the treatment of the metabolic syndrome

Metabolic syndrome is a collection of abnormalities, including at least three of the following insulin resistance, hypertension, dyslipidemia, type 2 diabetes, obesity, inflammation, and non-alcoholic fatty liver disease. 3D printed solid dosage forms have emerged as a promising tool enabling the fabrication of personalized medicines and offering solutions that cannot be achieved by industrial mass production. Most attempts found in the literature to manufacture polypills for this syndrome contain just two drugs. However, most fixed-dose combination (FDC) products in clinical practice required the use of three or more drugs. In this work, Fused deposition modelling (FDM) 3D printing technology coupled with Hot-melt extrusion (HME) has been successfully applied in the manufacture of polypills containing nifedipine (NFD), as an antihypertensive drug, simvastatin (SMV), as an antihyperlipidemic drug, and gliclazide (GLZ) as an antiglycemic drug. Hanssen solubility parameters (HSPs) were utilized as predictors to guide the formation of amorphous solid dispersion between drug and polymer to ensure miscibility and enhanced oral bioavailability. The HSP varied from 18.3 for NFD, 24.6 for SMV, and 7.0 for GLZ while the total solubility parameter for the excipient mixture was 27.3^0.5. This allowed the formation of an amorphous solid dispersion in SMV and GLZ 3D printed tablets compared to NFD which was partially crystalline. Popypill showed a dual release profile combining a faster SMV release (< 6 h) with a 24 h sustained release for NDF and GLZ. This work demonstrated the transformation of FDC into dynamic dose-personalized polypills.

Cocrystals by Design: A Rational Coformer Selection Approach for Tackling the API Problems

Active pharmaceutical ingredients (API) with unfavorable physicochemical properties and stability present a significant challenge during their processing into final dosage forms. Cocrystallization of such APIs with suitable coformers is an efficient approach to mitigate the solubility and stability concerns. A considerable number of cocrystal-based products are currently being marketed and show an upward trend. However, to improve the API properties by cocrystallization, coformer selection plays a paramount role. Selection of suitable coformers not only improves the drug's physicochemical properties but also improves the therapeutic effectiveness and reduces side effects. Numerous coformers have been used till date to prepare pharmaceutically acceptable cocrystals. The carboxylic acid-based coformers, such as fumaric acid, oxalic acid, succinic acid, and citric acid, are the most commonly used coformers in the currently marketed cocrystal-based products. Carboxylic acid-based coformers are capable of forming the hydrogen bond and contain smaller carbon chain with the APIs. This review summarizes the role of coformers in improving the physicochemical and pharmaceutical properties of APIs, and deeply explains the utility of afore-mentioned coformers in API cocrystal formation. The review concludes with a brief discussion on the patentability and regulatory issues related to pharmaceutical cocrystals.

Targeting lung macrophages for fungal and parasitic pulmonary infections with innovative amphotericin B dry powder inhalers

The incidence of fungal pulmonary infections is known to be on the increase, and yet there is an alarming gap in terms of marketed antifungal therapies that are available for pulmonary administration. Amphotericin B (AmB) is a highly efficient broad-spectrum antifungal only marketed as an intravenous formulation. Based on the lack of effective antifungal and antiparasitic pulmonary treatments, the aim of this study was to develop a carbohydrate-based AmB dry powder inhaler (DPI) formulation, prepared by spray drying. Amorphous AmB microparticles were developed by combining 39.7 % AmB with 39.7 % γ-cyclodextrin, 8.1 % mannose and 12.5 % leucine. An increase in the mannose concentration from 8.1 to 29.8 %, led to partial drug crystallisation. Both formulations showed good in vitro lung deposition characteristics (80 % FPF < 5 µm and MMAD < 3 µm) at different air flow rates (60 and 30 L/min) when used with a DPI, but also during nebulisation upon reconstitution in water.

Can amphotericin B and itraconazole be co-delivered orally? Tailoring oral fixed-dose combination coated granules for systemic mycoses

The incidence and prevalence of invasive fungal infections have increased significantly over the last few years, leading to a global health problem due to the lack of effective treatments. Amphotericin B (AmB) and itraconazole (ITR) are two antifungal drugs with different mechanisms of action. In this work, AmB and ITR have been formulated within granules to elicit an enhanced pharmacological effect, while enhancing the oral bioavailability of AmB. A Quality by Design (QbD) approach was utilised to prepare fixed-dose combination (FDC) granules consisting of a core containing AmB with functional excipients, such as inulin, microcrystalline cellulose (MCC), chitosan, sodium deoxycholate (NaDC) and Soluplus® and polyvinyl pyrrolidone (PVP), coated with a polymeric layer containing ITR with Soluplus® or a combination of Poloxamer 188 and hydroxypropyl methyl cellulose-acetyl succinate (HPMCAS). A Taguchi design of experiments (DoE) with 7 factors and 2 levels was carried out to understand the key factors impacting on the physicochemical properties of the formulation followed by a Box-Behnken design with 3 factors in 3 levels chosen to optimise the formulation parameters. The core of the FDC granules was obtained by wet granulation and later coated using a fluidized bed. In vitro antifungal efficacy was demonstrated by measuring the inhibition halo against different species of Candida spp., including C. albicans (24.19-30.48 mm), C. parapsilosis (26.38-27.84 mm) and C. krusei (11.48-17.92 mm). AmB release was prolonged from 3 to 24 h when the AmB granules were coated. In vivo in CD-1 male mice studies showed that these granules were more selective towards liver, spleen and lung compared to kidney (up to 5-fold more selective in liver, with an accumulation of 8.07 µg AmB/g liver after twice-daily 5 days administration of granules coated with soluplus-ITR), resulting in an excellent oral administration option in the treatment of invasive mycosis. Nevertheless, some biochemical alterations were found, including a decrease in blood urea nitrogen (∼17 g/dl) and alanine aminotransferase (<30 U/l) and an increase in the levels of bilirubin (∼0.2 mg/dl) and alkaline phosphatase (<80 U/l), which could be indicative of a liver failure. Once-daily regimen for 10 days can be a promising therapy.

3D Printing Technologies in Personalized Medicine, Nanomedicines, and Biopharmaceuticals

3D printing technologies enable medicine customization adapted to patients' needs. There are several 3D printing techniques available, but majority of dosage forms and medical devices are printed using nozzle-based extrusion, laser-writing systems, and powder binder jetting. 3D printing has been demonstrated for a broad range of applications in development and targeting solid, semi-solid, and locally applied or implanted medicines. 3D-printed solid dosage forms allow the combination of one or more drugs within the same solid dosage form to improve patient compliance, facilitate deglutition, tailor the release profile, or fabricate new medicines for which no dosage form is available. Sustained-release 3D-printed implants, stents, and medical devices have been used mainly for joint replacement therapies, medical prostheses, and cardiovascular applications. Locally applied medicines, such as wound dressing, microneedles, and medicated contact lenses, have also been manufactured using 3D printing techniques. The challenge is to select the 3D printing technique most suitable for each application and the type of pharmaceutical ink that should be developed that possesses the required physicochemical and biological performance. The integration of biopharmaceuticals and nanotechnology-based drugs along with 3D printing ("nanoprinting") brings printed personalized nanomedicines within the most innovative perspectives for the coming years. Continuous manufacturing through the use of 3D-printed microfluidic chips facilitates their translation into clinical practice.

Effect of Primary Packaging Material on the Stability Characteristics of Diazepam and Midazolam Parenteral Formulations

Diazepam and midazolam are formulated in autoinjectors for parenteral administration to decrease seizures in the case of emergency. However, the compatibility of these lipophilic drugs with the primary packaging material is a key part of drug formulation development. In this work, diazepam and midazolam were packaged in glass syringes as parenteral solutions using two different elastomeric sealing materials (PH 701/50 C BLACK and 4023/50 GRAY). Syringes were stored at three different storage temperatures: 4, 25, and 40 °C. At different time points over 3 years, physical appearance, benzodiazepine sorption on the sealing elastomeric materials, and drug content in solution were assayed. A detailed study on the adsorption profile of both benzodiazepines on the elastomeric gaskets was performed, indicating that the novel rubber material made of bromobutyl derivatives (4023/50 GRAY) is a better choice for manufacturing autoinjectors due to lower drug adsorption. Diazepam showed a better stability profile than midazolam, with the latter solubilised as a hydrochloride salt in an acidic pH that can affect the integrity of the elastomer over time. The amount of drug adsorbed on the surface of the elastomer was measured by NIR and correlated using chemometric models with the amount retained in the elastomeric gaskets quantified by HPLC.

Cocrystals of tuberculosis antibiotics: Challenges and missed opportunities

Cocrystals have been extensively used to improve the physicochemical properties and bioavailability of active pharmaceutical ingredients. Cocrystals of anti-tuberculosis medications are among those commonly reported. This review provides a summary of the tuberculosis antibiotic cocrystals reported in the literature, providing the main results on current tuberculosis medications utilized in cocrystals. Moreover, anti-tuberculosis cocrystals limitations and advantages are described, including evidence for enhanced solubility, stability and effect. Opportunities to enhance anti-tuberculosis medications and fixed dose combinations using cocrystals are given. Several cocrystal pairs are suggested to enhance the effectiveness of anti-tuberculosis drugs.

Solid-State and Particle Size Control of Pharmaceutical Cocrystals using Atomization-Based Techniques

Poor bioavailability and aqueous solubility represent a major constraint during the development of new API molecules and can influence the impact of new medicines or halt their approval to the market. Cocrystals offer a novel and competitive advantage over other conventional methods with respect towards the substantial improvement in solubility profiles relative to the single-API crystals. Furthermore, the production of such cocrystals through atomization-based methods allow for greater control, with respect to particle size reduction, to further increase the solubility of the API. Such atomization-based methods include supercritical fluid methods, conventional spray drying and electrohydrodynamic atomization/electrospraying. The influence of process parameters such as solution flow rates, pressure and solution concentration, in controlling the solid-state and final particle size are discussed in this review with respect to atomization-based methods. For the last decade, literature has been attempting to catch-up with new regulatory rulings regarding the classification of cocrystals, due in part to data sparsity. In recent years, there has been an increase in cocrystal publications, specifically employing atomization-based methods. This review considers the benefits to employing atomization-based methods for the generation of pharmaceutical cocrystals, examines the most recent regulatory changes regarding cocrystals and provides an outlook towards the future of this field.

Development of Advanced 3D-Printed Solid Dosage Pediatric Formulations for HIV Treatment

The combination of lopinavir/ritonavir remains one of the first-line therapies for the initial antiretroviral regimen in pediatric HIV-infected children. However, the implementation of this recommendation has faced many challenges due to cold-chain requirements, high alcohol content, and unpalatability for ritonavir-boosted lopinavir syrup. In addition, the administration of crushed tablets has shown a detriment for the oral bioavailability of both drugs. Therefore, there is a clinical need to develop safer and better formulations adapted to children’s needs. This work has demonstrated, for the first time, the feasibility of using direct powder extrusion 3D printing to manufacture personalized pediatric HIV dosage forms based on 6 mm spherical tablets. H-bonding between drugs and excipients (hydroxypropyl methylcellulose and polyethylene glycol) resulted in the formation of amorphous solid dispersions with a zero-order sustained release profile, opposite to the commercially available formulation Kaletra, which exhibited marked drug precipitation at the intestinal pH.

Crystal engineering of a co-crystal of antipyrine and 2-chlorobenzoic acid: relative energetic contributions based on multipolar refinement

The growth and stability of a new 1 : 1 antipyrene–dichlorobenzoic acid cocrystal system has been analyzed in terms of electron density analysis and electrostatic interaction energy contributions.

Engineering 3D Printed Microfluidic Chips for the Fabrication of Nanomedicines

Currently, there is an unmet need to manufacture nanomedicines in a continuous and controlled manner. Three-dimensional (3D) printed microfluidic chips are an alternative to conventional PDMS chips as they can be easily designed and manufactured to allow for customized designs that are able to reproducibly manufacture nanomedicines at an affordable cost. The manufacturing of microfluidic chips using existing 3D printing technologies remains very challenging because of the intricate geometry of the channels. Here, we demonstrate the manufacture and characterization of nifedipine (NFD) polymeric nanoparticles based on Eudragit L-100 using 3D printed microfluidic chips with 1 mm diameter channels produced with two 3D printing techniques that are widely available, stereolithography (SLA) and fuse deposition modeling (FDM). Fabricated polymeric nanoparticles showed good encapsulation efficiencies and particle sizes in the range of 50-100 nm. SLA chips possessed better channel resolution and smoother channel surfaces, leading to smaller particle sizes similar to those obtained by conventional manufacturing methods based on solvent evaporation, while SLA manufactured nanoparticles showed a minimal burst effect in acid media compared to nanoparticles fabricated with FDM chips. Three-dimensional printed microfluidic chips are a novel and easily amenable cost-effective strategy to allow for customization of the design process for continuous manufacture of nanomedicines under controlled conditions, enabling easy scale-up and reducing nanomedicine development times, while maintaining high-quality standards.

Dry and Wet Mechanochemical Synthesis of Piroxicam and Saccharin Co-Crystals and Evaluation by Powder X-Ray Diffraction, Thermal Analysis and Mid- and Near- Infrared Spectroscopy

The purpose of this study is to investigate the effects of dry and wet mechanochemical synthesis on piroxicam (PX) and saccharin (SA) mixtures. For this purpose, PX and SA mixtures prepared by wet mechanochemical processes using three solvents and by dry mechanochemical synthesis were evaluated by mid-and near-infrared spectroscopy, powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC). The mixtures of wet-type products were transformed into PX/SA 1:1 co-crystals. The effect of the solvent was key to the co-crystallization of PX and SA. The products from the dry process were transformed into the amorphous phase. For the sample of the amorphous mixture, two exothermic peaks due to crystallization were observed in the thermal analysis. Bulk PX was ground for the same number of times for transformation, but was not successfully transformed to the amorphous bulk; the same was observed for SA. It is suggested that the mutual existence of PX and SA promotes mutual amorphization.

Impact of Crystal Habit on the Dissolution Rate and In Vivo Pharmacokinetics of Sorafenib Tosylate

The dissolution rate is the rate-limiting step for Biopharmaceutics Classification System (BCS) class II drugs to enhance their in vivo pharmacokinetic behaviors. There are some factors affecting the dissolution rate, such as polymorphism, particle size, and crystal habit. In this study, to improve the dissolution rate and enhance the in vivo pharmacokinetics of sorafenib tosylate (Sor-Tos), a BCS class II drug, two crystal habits of Sor-Tos were prepared. A plate-shaped crystal habit (ST-A) and a needle-shaped crystal habit (ST-B) were harvested by recrystallization from acetone (ACN) and n-butanol (BuOH), respectively. The surface chemistry of the two crystal habits was determined by powder X-ray diffraction (PXRD) data, molecular modeling, and face indexation analysis, and confirmed by X-ray photoelectron spectroscopy (XPS) data. The results showed that ST-B had a larger hydrophilic surface than ST-A, and subsequently a higher dissolution rate and a substantial enhancement of the in vivo pharmacokinetic performance of ST-B.

New Sodium Mefenamate - Nicotinamide Multicomponent Crystal Development to Modulate Solubility and Dissolution: Preparation, Structural, and Performance Study

A cocrystal of mefenamic acid (MA) - nicotinamide (NA) has been reported to increase the solubility of MA, but it still does not exceed the solubility of sodium mefenamate (SM). Accordingly, this research dealt with a new salt cocrystal arrangement of SM - NA. Cocrystal screening was performed, followed by powder and single-crystal preparation. Solvent drop grinding and slow evaporation at cold and ambient temperatures were employed to produce the multicomponent crystal. Two new salt cocrystals were found as hemihydrates and monohydrates, named SMN-HH and SMN-MH, respectively. SMN-MH single crystals were successfully isolated and structurally analyzed using a single crystal X-ray diffractometer. Pharmaceutical properties were investigated, including hydrate stability, solubility, and intrinsic dissolution. The experiments showed that the hemihydrate was stable under ambient humidity and temperature, and that the monohydrate rapidly changed to hemihydrate. Both hydrates improved the solubility and intrinsic dissolution of SM, but SMN-HH was superior. The data showed that SMN salt cocrystals combine the advantages of salt and cocrystals and show potential for dosage form development.

Amelioration of physicochemical, pharmaceutical, and pharmacokinetic properties of lornoxicam by cocrystallization with a novel coformer

OBJECTIVE

The present study was aimed to prepare and characterize new cocrystals of lornoxicam (LORX), a BCS class II drug employing 1,3-dimethyl urea (DMU) as a coformer to improve physicochemical, pharmaceutical, and pharmacokinetic performance.

METHODS

A screening study was conducted by employing three techniques viz. neat grinding, liquid-assisted grinding (LAG), and solvent evaporation (SE) using different drug-coformer molar ratios (1:1, 1:2, and 1:3). Samples were characterized by DSC, PXRD, ATR-FTIR, SEM, intrinsic dissolution rate (IDR) studies, compressional studies, and pharmacokinetic studies. In vitro dissolution and stability studies (25 °C/60%RH and 40 °C/75%RH for three months) were carried out for cocrystal tablets.

RESULTS

LAG and SE were found successful in ratio 1:3 and IDR showed approximately 28- and 19-fold increase, respectively in 0.1 N HCl (pH 1.2) and buffer (pH 7.4) as compared to pure LORX. The cocrystal exhibited good tabletability and was ∼2.5 times that of LORX at 6000 Psi. Dissolution profiles of tablets of cocrystal increased (56% and 100% at pH 1.2 and 7.4, respectively in contrast to those of physical mixture (PhyMix) (∼35% and ∼10%) and pure LORX (∼17% and ∼7%) within 60 min. The C_max and AUC_0-∞ for the selected cocrystal were significantly increased (p < 0.05) which was 2.4 and 2.5 times, respectively, that of LORX in a single dose oral pharmacokinetic study executed in rabbits. Tablets of cocrystal were found stable at both conditions.

CONCLUSION

The study indicates that cocrystallization with DMU can concomitantly improve tabletability, dissolution rate, and in vivo performance of dissolution limited drug LORX.

3D printed spherical mini-tablets: Geometry versus composition effects in controlling dissolution from personalised solid dosage forms

Oral dosage forms are by far the most common prescription and over-the-counter pharmaceutical dosage forms used worldwide. However, many patients suffer from adverse effects caused by their use of "one-size fits all" mass produced commercially available solid dosage forms, whereby they do not receive dedicated medication or dosage adjusted to their specific needs. The development of 3D printing paves the way for personalised medicine. This work focuses on personalised therapies for hypertensive patients using nifedipine as the model drug. 3D printed full solid and channelled spherical mini-tablets with enhanced surface area (1.6-fold higher) were printed using modified PVA commercial filaments loaded by passive diffusion (PD), and Kollidon VA64 (KVA) and ethylcellulose (EC) based filaments prepared by hot-melt extrusion (HME). Drug loading ranged from 3.7% to 60% based on the employed technique, with a 13-fold higher drug loading achieved with the HME compared to PD. Composition was found to have a more significant impact on drug dissolution than geometry and surface area. Both KVA and EC-based formulations exhibited a biphasic zero-order drug-release profile. Physicochemical characterization revealed that nifedipine was in the amorphous form in the KVA-based end-products which led to a greater dissolution control over a 24 h period compared to the EC-based formulations that exhibited low levels of crystallinity by PXRD. The proposed 3D printed spherical mini-tablets provide a versatile technology for personalised solid dosage forms with high drug loading and dissolution control, easily adaptable to patient and disease needs.

Spectroscopic Methodology and Molecular Docking Studies on Changes in Binding Interaction of Felodipine with Bovine Serum Albumin Induced by Cocrystallization with β-Resorcylic Acid

In the present study, a novel cocrystal of felodipine (FEL) and β-resorcylic acid (βRA) was developed. We specially focused on the change of binding pattern with bovine serum albumin (BSA) induced by cocrystallization of FEL with βRA. The solid characterizations and density functional theory (DFT) simulation verified that FEL-βRA cocrystal formed in equimolar ratio (1 : 1 M ratio) through C=O^…H-O hydrogen bond between C=O group in FEL and O-H group in βRA. The binding interactions between FEL-βRA system and BSA were studied using fluorescence spectral and molecular docking methods. Two guest molecule systems, including a physical mixture of FEL and βRA and FEL-βRA cocrystal were performed binding to BSA in molecular docking. According to the K_b and binding energy, the supramolecular form of FEL-βRA system was retained during binding to BSA. Molecular docking simulation suggested that FEL and its cocrystal inserted into the subdomain IIIA (site II') of BSA. The interactions between FEL and BSA including hydrogen bonding with ASN390 residue and intermolecular hydrophobic interactions with LEU429 and LEU452 residues. However, the size of supramolecular FEL-βRA better matched that of active cavity of BSA; the cocrystal is closely bound to BSA through hydrogen bonding with ASN390 residue and intermolecular hydrophobic interactions with LEU429, VAL432, LEU452 and ILE387 residues. This change on binding affinity of FEL to BSA induced by cocrystallization with βRA provided theoretical basis to evaluate the transportation, distribution and metabolism of cocrystal drug.

Impact of Crystal Habit on Solubility of Ticagrelor

Drugs with poor biopharmaceutical performance are the main obstacle to the development and design of medicinal preparations. The anisotropic surface chemistry of different surfaces on the crystal influences its physical and chemical properties, such as solubility, tableting, etc. In this study, the antisolvent crystallization and rapid-cooling crystallization were carried out to tune the crystal habits of ticagrelor (TICA) form II. Different crystal habits of ticagrelor (TICA) form II (TICA-A, TICA-B, TICA-C, TICA-D, and TICA-E) were prepared and evaluated for solubility. The single-crystal diffraction (SXRD) indicated that TICA form II belongs to the triclinic P1 space group with four TICA molecules in the asymmetric unit. The TICA molecules are generated through intermolecular hydrogen bonds along the (010) direction, forming an infinite molecular chain, which are further stacked by hydrogen bonds between hydroxyethoxy side chains, forming molecular circles composed of six TICA molecules along bc directions. Thus, in the case of TICA form II, hydrogen bonds drive growth along one axis (b-axis), which results in the formation of mostly needle-shape crystals. Morphology and face indexation reveals that (001), (010) and (01-1) are the main crystal planes. Powder diffractions showed that five habits have the same crystal structure and different relative intensity of diffraction peak. The solubility of the obtained crystals showed the crystal habits affect their solubility. This work is helpful for studying the mechanism of crystal habit modification and its effect on solubility.

Tuning the Transdermal Delivery of Hydroquinone upon Formulation with Novel Permeation Enhancers

Hydroquinone (HQ) is an anti-hyperpigmentation agent with poor physicochemical stability. HQ formulations are currently elaborated by compounding in local pharmacies. Variability in the characteristics of HQ topical formulations can lead to remarkable differences in terms of their stability, efficacy, and toxicity. Four different semisolid O/W formulations with 5% HQ were prepared using: (i) Beeler´s base plus antioxidants (F1), (ii) Beeler´s base and dimethyl isosorbide (DMI) as solubiliser (F2), (iii) olive oil and DMI (F3), and (iv) Nourivan^®, a skin-moisturising and antioxidant base, along with DMI (F4). Amongst the four formulations, F3 showed the greatest physicochemical stability with less tendency to coalescence but with marked chromatic aberrations. An inverse correlation was established by multivariate analysis between the mean droplet size in volume and the steady-state flux, which explains why F3, with the smallest droplet size and the most hydrophobic excipients, exhibited the highest permeation across both types of membranes with enhancement ratios of 2.26 and 5.67-fold across Strat-M^® and mouse skin, respectively, compared to F1. It is crucial to understand how the HQ is formulated, bearing in mind that the use of different excipients can tune the transdermal delivery of HQ significantly.

In Situ Cocrystallization of Dapsone and Caffeine during Fluidized Bed Granulation Processing

Different pharmaceutical manufacturing processes have been demonstrated to represent feasible platforms for the production of pharmaceutical cocrystals. However, new methods are needed for the manufacture of cocrystals on a large scale. In this work, the suitability of the use of a fluidized bed system for granulation and concomitant cocrystallization was investigated. Dapsone (DAP) and caffeine (CAF) have been shown to form a stable cocrystal by simple solvent evaporation. DAP is the active pharmaceutical ingredient (API) and CAF is the coformer. In the present study, DAP-CAF cocrystals were produced through liquid-assisted milling and the product obtained was used as a cocrystal reference. The granulation of DAP and CAF was carried out using four different experimental conditions. The solid-state properties of the constituents of the granules were characterised by differential scanning calorimetry (DSC) and x-ray powder diffraction (PXRD) analysis while the granule size distribution and morphology were investigated using laser diffraction and scanning electron microscopy (SEM), respectively. DAP-CAF cocrystal granules were successfully produced during fluidized bed granulation. The formation of cocrystals was possible only when the DAP and CAF were dissolved in the liquid phase and sprayed over the fluidized solid particles. Furthermore, the presence of polymers in solution interferes with the cocrystallization, resulting in the amorphization of the DAP and CAF. Cocrystallization via fluidized bed granulation represents a useful tool and a feasible alternative technique for the large scale manufacture of pharmaceutical cocrystals for solid dosage forms.

Engineering Cocrystals of PoorlyWater-Soluble Drugs to Enhance Dissolution in Aqueous Medium

Biopharmaceutics Classification System (BCS) Class II and IV drugs suffer from poor aqueous solubility and hence low bioavailability. Most of these drugs are hydrophobic and cannot be developed into a pharmaceutical formulation due to their poor aqueous solubility. One of the ways to enhance the aqueous solubility of poorlywater-soluble drugs is to use the principles of crystal engineering to formulate cocrystals of these molecules with water-soluble molecules (which are generally called coformers). Many researchers have shown that the cocrystals significantly enhance the aqueous solubility of poorly water-soluble drugs. In this review, we present a consolidated account of reports available in the literature related to the cocrystallization of poorly water-soluble drugs. The current practice to formulate new drug cocrystals with enhanced solubility involves a lot of empiricism. Therefore, in this work, attempts have been made to understand a general framework involved in successful (and unsuccessful) cocrystallization events which can yield different solid forms such as cocrystals, cocrystal polymorphs, cocrystal hydrates/solvates, salts, coamorphous solids, eutectics and solid solutions. The rationale behind screening suitable coformers for cocrystallization has been explained based on the rules of five i.e., hydrogen bonding, halogen bonding (and in general non-covalent bonding), length of carbon chain, molecular recognition points and coformer aqueous solubility. Different techniques to screen coformers for effective cocrystallization and methods to synthesize cocrystals have been discussed. Recent advances in technologies for continuous and solvent-free production of cocrystals have also been discussed. Furthermore, mechanisms involved in solubilization of these solid forms and the parameters influencing dissolution and stability of specific solid forms have been discussed. Overall, this review provides a consolidated account of the rationale for design of cocrystals, past efforts, recent developments and future perspectives for cocrystallization research which will be extremely useful for researchers working in pharmaceutical formulation development.

Advanced methodologies for cocrystal synthesis

Pharmaceutical cocrystals are multicomponent systems composed of two or more molecules and held together by H-bonding. Currently, cocrystals provide exciting opportunities in the pharmaceutical industry for the development and manufacturing of new medicines by improving poor physical properties of Active Pharmaceutical Ingredients (APIs) such as processability, solubility, stability and bioavailability. According to the recent reclassification, cocrystals are considered as drug polymorph rather a new API which has a significant impact on drug development, regulatory submissions and intellectual property protection. This review summarizes recent trends and advances in synthesis, manufacturing and scale - up of cocrystals. The operational principles of several cocrystals manufacturing technologies are discussed including their advantages and disadvantages in terms of crystal quality, purity stability, throughput and limitations in large scale production.