Improving mechanical properties of desloratadine via multicomponent crystal formation

Multicomponent Crystal of Trimethoprim and Citric Acid: Solid State Characterization and Dissolution Rate Studies

BACKGROUND: Trimethoprim is a broad spectrum antimicrobial agent with low solubility in water which causes low bioavailability in systemic circulation. AIM: The purpose of this study was to prepare multicomponent crystals of trimethoprim and citric acid to increase the solubility and dissolution rate of trimethoprim. MATERIALS AND METHODS: Multicomponent crystals were prepared by solvent evaporation method. Characterizations of multicomponent crystalline solid phase properties were carried out by powder X-ray diffraction (PXRD) analysis, differential scanning calorimetry (DSC), FT-IR spectroscopy, scanning electron microscopy (SEM). Solubility and dissolution rate tests were carried out in aqueous medium. RESULTS: The PXRD characterization results showed a new X-ray diffraction pattern in the multicomponent crystal phase. DSC analysis showed the formation of a new endothermic peak. This indicates the formation of a multicomponent crystal phase between trimethoprim and citric acid. The results of the SEM analysis indicate the formation of a new crystal habit. Solubility of multi-component crystal phase of trimethoprim increased 7 times compared to intact trimethoprim. The dissolution of trimethoprim and multicomponent crystals in 0.1 N HCl medium at 60 minutes was 56.36% and 95.57% and CO2-free distilled water medium was 43.03% and 88.26%, respectively. CONCLUSIONS: From the results of the study, it can be concluded that the multicomponent phase of trimethoprim crystals with citric acid successfully increase the solubility and dissolution rate of trimethoprim significantly.

Energy framework and solubility: a new predictive model in the evaluation of the structure–property relationship of pharmaceutical solid forms

Crystal structures with lower interaction energy tend to present higher aqueous solubility.

Modulation of the powder properties of lamotrigine by crystal forms

The mechanical properties of powders determine the ease of manufacture and ultimately the quality of the oral solid dosage forms. Although poor mechanical properties of an active pharmaceutical ingredient (API) can be mitigated by using suitable excipients in a formulation, the effectiveness of that approach is limited for high dose drugs or multidrug tablets. In this context, improving the mechanical properties of the APIs through solid form optimisation is a good strategy to address such a challenge. This work explores the powder and tableting properties of various lamotrigine (LAM) solid forms with the aim to facilitate direct compression by overcoming the poor tabletability of LAM. The two drug-drug crystals of LAM with nicotinamide and valproic acid demonstrate superior flowability and tabletability over LAM. The improved powder properties are rationalised by structure analysis using energy framework, scanning electron microscopy, and Heckel analysis.

Density functional theory predictions of the mechanical properties of crystalline materials

The DFT-predicted mechanical properties of crystalline materials are crucial knowledge for their screening, design, and exploitation.

Evaluation of Thermal-Induced Polymorphic Transformation on Desloratadine and Desloratadine-Benzoic Acid Salt

Background: Active pharmaceutical ingredients face a challenge in manufacturing due to adverse physicomechanical properties. Desloratadine (DES) form I exhibits poor mechanical behavior through the formation of capping during the tableting process. Salt formation from DES and benzoic acid (BA) has been observed to resolve poor mechanical properties. However, the ability to withstand heat from the manufacturing process should be implemented in DES and DES-BA salt. The aim of this study was to determine the differences between thermal treatment results on DES and DES-BA salt and whether it causes them to undergo polymorphic transformation. Methods: Salt was crystallized between DES and BA using the solvent evaporation method. DES and DES-BA salt were heated at 110°C, 159°C (melting point of DES), 181°C (melting point of DES-BA), and 190°C. Following this, characterization was performed using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and solubility testing. Results: Polymorphic transformation caused by heat occurred in DES, but not in DES-BA salt. The transformation of DES was induced by the effect of heating, which changed polymorph I to a mixture of polymorph I and III at 110°C, to polymorph II at 159°C, and to a mixture of polymorph I, II, and III at 190°C. Under 190oC, DES-BA is still stable and did not undergo a polymorphic transformation. However, at 190oC, decomposition started to occur, which implied decreased solubility, which did not occur in DES. Conclusion: The heating process did not cause DES-BA salt to undergo a polymorphic transformation. However, it caused decomposition at 190oC. DES underwent a polymorphic transformation when exposed to the same condition without decomposition. This provided information to always pay attention to temperature during manufacturing processes that include DES or DES-BA salt to avoid physicochemical changes.

Cocrystallization: Cutting Edge Tool for Physicochemical Modulation of Active Pharmaceutical Ingredients

Cocrystallization is a widely accepted and clinically relevant technique that has prospered very well over the past decades to potentially modify the physicochemical properties of existing active pharmaceutic ingredients (APIs) without compromising their therapeutic benefits. Over time, it has become an integral part of the pre-formulation stage of drug development because of its ability to yield cocrystals with improved properties in a way that other traditional methods cannot easily achieve. Cocrystals are solid crystalline materials composed of two or more than two molecules which are non-covalently bonded in the same crystal lattice. Due to the continuous efforts of pharmaceutical scientists and crystal engineers, today cocrystals have emerged as a cutting edge tool to modulate poor physicochemical properties of APIs such as solubility, permeability, bioavailability, improving poor mechanical properties and taste masking. The success of cocrystals can be traced back by looking at the number of products that are getting regulatory approval. At present, many cocrystals have obtained regulatory approval and they successfully made into the market place followed by a fair number of cocrystals that are currently in the clinical phases. Considering all these facts about cocrystals, the formulation scientists have been inspired to undertake more relevant research to extract out maximum benefits. Here in this review cocrystallization technique will be discussed in detail with respect to its background, different synthesis approaches, synthesis mechanism, application and improvements in drug delivery systems and its regulatory perspective.

Improved Solubility and Dissolution Rates in Novel Multicomponent Crystals of Piperine with Succinic Acid

The objectives of this study were to prepare and characterize a novel piperine–succinic acid multicomponent crystal phase and to evaluate the improvement in the solubility and dissolution rate of piperine when prepared in the multicomponent crystal formation. The solid-state characterization of the novel multicomponent crystal was performed by powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform-infrared (FT-IR) spectroscopy. Solubility and dissolution rate profiles were evaluated in distilled water. The physical stability was evaluated under high relative humidity (75% and 100% RH). The determination of the single crystal X-ray diffraction structure revealed that this novel multicomponent crystal was a cocrystalline phase of piperine–succinic acid (2:1 molar ratio). The differential scanning calorimetry thermogram of the cocrystal showed a single and sharp endothermic peak at 110.49 °C. The cocrystal resulted in greater solubility and a faster dissolution rate of piperine than intact piperine. This improvement was a result of the formation of a channel structure in the cocrystal. In addition, the cocrystal was stable under a humid condition.

Crystal Structural Analysis of DL-Mandelate Salt of Carvedilol and Its Correlation with Physicochemical Properties

A 1:1 salt of carvedilol (CVD), an anti-hypertensive drug, with DL-mandelic acid (DL-MA) was crystallized from ethanol and the structure was characterized by X-ray single-crystal diffraction, revealing salt formation by transfer of an acidic proton from the COOH group of MA to the aliphatic (acyclic) secondary amino NH group of CVD. The crystal structure is triclinic, with a P-1 space group and unit cell parameters a = 9.8416(5) Å, b = 11.4689(5) Å, c = 14.0746(7) Å, α = 108.595(8), β = 95.182(7), γ = 107.323(8), V = 1406.95(15) Å3, and Z = 2. The asymmetric unit contained one protonated CVD and one MA anion, linked via an N+–H∙∙∙O¯ strong hydrogen bond and a ratio of 1:1. As previously reported, the thermal, spectroscopic, and powder X-ray diffraction properties of the salt of CVD with DL-MA (CVD_DL-MA) differed from CVD alone. The intrinsic dissolution rate of CVD_DL-MA was about 10.7 times faster than CVD alone in a pH 6.8 buffer.

Multicomponent Crystal of Mefenamic Acid and N-Methyl-d-Glucamine: Crystal Structures and Dissolution Study

A novel multicomponent crystal (MC) of mefenamic acid (MA) and N-methyl-d-glucamine (MG) had been prepared to improve the physicochemical properties of poorly soluble drugs, and was characterized for its physicochemical properties by powder X-ray diffraction analysis, differential scanning calorimetry thermal analysis, FT-IR spectroscopy, in vitro dissolution rate, and physical stability. In addition, the crystal structure was determined by single-crystal X-ray diffraction analysis. The differential scanning calorimetry thermogram of the MA-MG binary system exhibits a single and sharp endothermic peak at 151.20°C, which was attributed to the melting point of a MC of MA-MG. FT-IR spectroscopy analysis showed the occurrence of solid-state interaction by involving proton transfer between MA and MG. The crystal structure analysis confirmed that MA-MG formed 1:1 ratio salt type MC. The formation of a MC of MA with MG significantly improved the dissolution rate of MA in compared to intact MA, and also the crystal demonstrated a good stability under a high relative humidity. These good properties would be attributed to the layer structure of MA and MG in the crystal.

A Novel Desloratadine-Benzoic Acid Co-Amorphous Solid: Preparation, Characterization, and Stability Evaluation

Low physical stability is the limitation of the widespread use of amorphous drugs. The co-amorphous drug system is a new and emerging method for preparing a stable amorphous form. Co-amorphous is a single-phase amorphous multicomponent system consisting of two or more small molecules that are a combination of drugs or drugs and excipients. The co-amorphous system that uses benzoic acid (BA) as an excipient was studied to improve the physical stability, dissolution, and solubility of desloratadine (DES). In this study, the co-amorphous formation of DES and BA (DES–BA) was prepared by melt-quenching method and characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), and polarized light microscopy (PLM). Dissolution, solubility, and physical stability profiles of DES–BA were determined. The DES crystals were converted into DES–BA co-amorphous form to reveal the molecular interactions between DES and BA. Solid-state analysis proved that the co-amorphous DES–BA system (1:1) is amorphous and homogeneous. The DSC experiment showed that the glass transition temperature (Tg) of tested DES–BA co-amorphous had a higher single Tg compared to the amorphous DES. FTIR revealed strong interactions, especially salt formation. The dissolution rate and solubility of co-amorphous DES–BA (1:1) obtained were larger than the DES in crystalline form. The PXRD technique was used to assess physical stability for three months at 40 °C with 75% RH. The DES–BA co-amorphous system demonstrated better physical stability than a single form of amorphous DES. Co-amorphous DES–BA has demonstrated the potential for improving solid-state stability, as the formation of DES–BA co-amorphous salt increased solubility and dissolution when compared to pure crystalline DES. This study also demonstrated the possibility for developing a DES–BA co-amorphous system toward oral formulations to improve DES solubility and bioavailability.

Solubility Improvement of Benexate through Salt Formation Using Artificial Sweetener

Benexate, a drug used clinically as a defensive type anti-ulcer agent, has poor solubility and a bitter taste. To improve its solubility, a crystal engineering approach was proposed with the formation of novel salts using an artificial sweetener as a salt co-former. This was also expected to address the bitter taste of the drug. In this work, we report on the preparation and evaluation of the physicochemical properties of the novel salts benexate saccharinate monohydrate and benexate cyclamate whose crystal structures were determined by single-crystal X-ray structure analysis. These novel salts showed higher solubility and faster dissolution profiles that were associated with the occurrence of local layered-like structures. They also showed better moisture uptake profiles and were classified as non-hygroscopic materials. Therefore, benexate saccharinate monohydrate and benexate cyclamate expedited the development of sweet pharmaceutical salts of benexate with improved performances.

Synthesis, characterization, and stability study of desloratadine multicomponent crystal formation

This study describes the formation of multicomponent crystal (MCC) of desloratadine (DES). The objective of this study was to discover the new pharmaceutical MCC of DES using several coformers. The MCC synthesis was performed between DES and 26 coformers using an equimolar ratio with a solvent evaporation technique. The selection of the appropriate solvent was carried out using 12 solvents. The preview of the MCC of DES was performed using polarized light microscopy (PLM). The formation of MCC was confirmed using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The accelerated stability of MCC at 40 °C and relative humidity of 75% was investigated using PXRD and FTIR. Depending on the prior evaluation, DES and benzoic acid (BA) formed the MCC. PLM and SEM results showed that crystal habit of combination between DES and BA differed from the constituent components. Moreover, the diffractogram pattern of DES-BA was distinct from the constituent components. The DSC thermogram showed a new peak which was distinct from both constituent components. The FTIR study proved a new spectrum. All characterizations indicated that a new solid crystal was formed, ensuring the MCC formation. In addition, DES-BA MCC had both chemical and physical stabilities for a period of 4 months.