Pharmaceutical Cocrystal of Piroxicam: Design, Formulation and Evaluation

Comparative assessment of solubility enhancement of itroconazole by solid dispersion and co-crystallization technique: Investigation of simultaneous effect of media composition on drug dissolution

Solubility of the drug is an important property of the drug as it affects the release, absorption, dissolution rate and ultimately bioavailability of the drug. Hence, the poorly aqueous soluble drug, need to be processed, to enhance its solubility and dissolution. The Biopharmaceutical System of Classification (BCS) II drugs are poorly soluble and have high permeability. Though their good ability to permeate through the membrane make them clinically useful but the problem associated with the solubility restrict their clinical use. Therefore, there is need to improve the solubility of such drug molecules to get effective pharmacological action. Itraconazole (ITZ) is an antifungal agent used in the treatment of fungal infections having poor aqueous solubility as belonging to BCS class II. The present study was aim to enhance the solubility of ITZ by solid dispersion and co-crystallization techniques. Investigation of simultaneous effect of media composition on drug dissolution was also the objective of this work. The ITZ-SD and ITZ-CCs were prepared from ITZ and other excipients like PEG 4000, oxalic acid, fumaric and malic acid by solvent evaporation, kneading technique, slurry conversion and solvent drop grinding methods. The prepared ITZ-SD, ITZ-OA-CCs, ITZ-FA-CCs and ITZ-MA-CCs were evaluated for FTIR, DSC, PXRD, % yield, micromeritic properties. The optimized ITZ-SD and ITZ-CCs were used to compress a tablet and subject to post-compression parameters. The results of FTIR and DSC showed the absence of interaction between the drug and excipients. The PXRD pattern demonstrated the formation of crystalline structures with 6 folds increased in solubility during saturation solubility analysis. In vitro dissolution was carried out in dissolution media with different pH which shows the maximum release from ITZ-SD and ITZ-CCs in pH 6.8. This also revealed the highly pH dependent solubility and dissolution behavior of the weakly basic BCS class II drug (ITZ) with pKa value of 3.7. The overall results in this study indicated the potential of solid dispersion and co-crystals for enhancement of solubility of the poorly water-soluble drugs.

Using Prenucleation Aggregation of Caffeine-Benzoic Acid as a Rapid Indication of Co-crystallization from Solutions

Co-crystal design is a convenient way to remedy the poor biopharmaceutical properties of drugs. Most studies focus on experimental co-crystal screening or computational prediction, but hardly any work has been done toward fast, efficient, and reliable prediction of solution crystallization for co-crystal formation. Here, we study the caffeine-benzoic acid co-crystal system, due to its reported difficulty to crystallize from the solution phase. With this work, we investigate whether there is a link between prenucleation aggregation in solution and co-crystal formation and how to harness this for crystallization prediction. ¹H and ¹³C NMR spectroscopy is used to study the prenucleation interaction between caffeine and benzoic acid in methanol, acetone, and acetonitrile as examples of common solvents. In this system, crystallization from methanol leads to no co-crystallization, from acetone to concomitant crystallization of co-crystal and caffeine, and from acetonitrile to pure co-crystal formation from solution. Strong heteromeric dimers were found to exist in all three solvents. Ternary phase diagrams were defined and a solution-accessible co-crystal region was found for all solvents. For this system, the prenucleation clusters found in solution could be linked to the crystallization of the co-crystal. Crystallization from DMSO did not yield the co-crystal and there were no detectable prenucleation aggregates. NMR spectroscopy to probe dimers in solution can thus be used as a fast, reliable, and promising tool to predict co-crystallization from specific solvents and to screen for suitable solvents for manufacturing and scale-up.

Co-crystal nanoarchitectonics as an emerging strategy in attenuating cancer: Fundamentals and applications

Cancer ranks as the second foremost cause of death in various corners of the globe. The clinical uses of assorted anticancer therapeutics have been limited owing to the poor physicochemical attributes, pharmacokinetic performance, and lethal toxicities. Various sorts of co-crystals or nano co-crystals or co-crystals-laden nanocarriers have presented great promise in targeting cancer via improved physicochemical attributes, pharmacokinetic performance, and reduced toxicities. These systems have also demonstrated the controlled cargo release and passive targeting via enhanced permeation and retention (EPR) effect. In addition, regional delivery of co-crystals via inhalation and transdermal route displayed remarkable potential in targeting lung and skin cancer effectively. However, more research is required on the use of co-crystals in cancer and their commercialization. The present review mainly emphasizes co-crystals as emerging avenues in the treatment of various cancers by modulating the physicochemical and pharmacokinetic attributes of approved anticancer therapeutics. The worth of co-crystals in cancer treatment, computational paths in the co-crystals screening, diverse experimental techniques of co-crystals fabrication, and sorts of co-crystals and their noteworthy applications in targeting cancer are also discussed. Besides, the game changer approaches like nano co-crystals and co-crystals-laden nanocarriers, and co-crystals in regional delivery in cancer are also explained with reported case studies. Furthermore, regulatory directives for pharmaceutical co-crystals and their scale-up, and challenges are also highlighted with concluding remarks and future initiatives. In essence, co-crystals and nano co-crystals emerge to be a promising strategy in overwhelming cancers through improving anticancer efficacy, safety, patient compliance, and reducing the cost.

Pharmaceutical Salts of Piroxicam and Meloxicam with Organic Counterions

Piroxicam (PRM) and meloxicam (MEL) are two nonsteroidal anti-inflammatory drugs, belonging to the Biopharmaceutics Classification System Class II drugs. In this study, six novel pharmaceutical salts of PRM and MEL with three basic organic counterions, that is, 4-aminopyridine (4AP), 4-dimethylaminopyridine (4DMP), and piperazine (PPZ), were prepared by both slurrying and slow evaporation. These salts were characterized by single-crystal and powder X-ray diffraction, thermal analysis, and Fourier transform infrared spectroscopy. All six salts, especially MEL-4DMP and MEL-4AP, showed a significantly improved apparent solubility and dissolution rate in sodium phosphate solution compared with the pure APIs. Notably, PRM-4AP and PRM-4DMP salts exhibited enhanced fluorescence, and the PRM-PPZ salt showed weaker fluorescence compared with that of pure PRM due to different luminescence mechanisms.

Effect of Surfactants and Polymers on the Dissolution Behavior of Supersaturable Tecovirimat-4-Hydroxybenzoic Acid Cocrystals

(1) Background: Pharmaceutical cocrystals have attracted remarkable interest and have been successfully used to enhance the absorption of poorly water-soluble drugs. However, supersaturable cocrystals are sometimes thermodynamically unstable, and the solubility advantages present a risk of precipitation because of the solution-mediated phase transformation (SMPT). Additives such as surfactants and polymers could sustain the supersaturation state successfully, but the effect needs insightful understanding. The aim of the present study was to investigate the roles of surfactants and polymers in the dissolution-supersaturation-precipitation (DSP) behavior of cocrystals. (2) Methods: Five surfactants (SDS, Poloxamer 188, Poloxamer 407, Cremophor RH 40, polysorbate 80) and five polymers (PVP K30, PVPVA 64, HPC, HPMC E5, CMC-Na) were selected as additives. Tecovirimat-4-hydroxybenzoic (TEC-HBA) cocrystals were chosen as a model cocrystal. The TEC-HBA cocrystals were first designed and verified by PXRD, DSC, SEM, and FTIR. The effects of surfactants and polymers on the solubility and dissolution of TEC-HBA cocrystals under sink and nonsink conditions were then investigated. (3) Results: Both the surfactants and polymers showed significant dissolution enhancement effects, and most of the polymers were more effective than the surfactants, according to the longer T_max and higher C_max. These results demonstrate that the dissolution behavior of cocrystals might be achieved by the maintained supersaturation effect of the additives. Interestingly, we found a linear relationship between the solubility and C_max of the dissolution curve for surfactants, while no similar phenomena were found in solutions with polymer. (4) Conclusions: The present study provides a basis for additive selection and a framework for understanding the behavior of supersaturable cocrystals in solution.

Challenges and Progress in Nonsteroidal Anti-Inflammatory Drugs Co-Crystal Development

Co-crystal innovation is an opportunity in drug development for both scientists and industry. In line with the “green pharmacy” concept for obtaining safer methods and advanced pharmaceutical products, co-crystallization is one of the most promising approaches to find novel patent drugs, including non-steroidal anti-inflammatory drugs (NSAID). This kind of multi-component system improves previously poor physicochemical and mechanical properties through non-covalent interactions. Practically, there are many challenges to find commercially viable co-crystal drugs. The difficulty in selecting co-formers becomes the primary problem, followed by unexpected results, such as decreased solubility and dissolution, spring and parachute effect, microenvironment pH effects, changes in instability, and polymorphisms, which can occur during the co-crystal development. However, over time, NSAID co-crystals have been continuously updated regarding co-formers selection and methods development.

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.

Amino Acids as the Potential Co-Former for Co-Crystal Development: A Review

Co-crystals are one of the most popular ways to modify the physicochemical properties of active pharmaceutical ingredients (API) without changing pharmacological activity through non-covalent interactions with one or more co-formers. A "green method" has recently prompted many researchers to develop solvent-free techniques or minimize solvents for arranging the eco-friendlier process of co-crystallization. Researchers have also been looking for less-risk co-formers that produce the desired API's physicochemical properties. This review purposed to collect the report studies of amino acids as the safe co-former and explored their advantages. Structurally, amino acids are promising co-former candidates as they have functional groups that can form hydrogen bonds and increase stability through zwitterionic moieties, which support strong interactions. The co-crystals and deep eutectic solvent yielded from this natural compound have been proven to improve pharmaceutical performance. For example, l-glutamine could reduce the side effects of mesalamine through an acid-base stabilizing effect in the gastrointestinal fluid. In addition, some amino acids, especially l-proline, enhances API's solubility and absorption in its natural deep eutectic solvent and co-crystals systems. Moreover, some ionic co-crystals of amino acids have also been designed to increase chiral resolution. Therefore, amino acids are safe potential co-formers, which are suitable for improving the physicochemical properties of API and prospective to be developed further in the dosage formula and solid-state syntheses.

Synthesis and Characterization of a (-)-Epicatechin and Barbituric Acid Cocrystal: Single-Crystal X-ray Diffraction and Vibrational Spectroscopic Studies

The paper presents the contribution of the cocrystallization method in the physicochemical modification of catechins that exhibit low oral bioavailability. This was done to obtain cocrystals for two naturally occurring polyphenolic diastereoisomers (+)-catechin and (-)-epicatechin with commonly used coformers. Due to distinct crystallization behavior, only the (-)-epicatechin cocrystal with barbituric acid in a 1:1 stoichiometry was obtained. The cocrystal of (-)-epicatechin (EC) with barbituric acid (BTA) was prepared by the slow solvent-evaporation technique. The structure and intermolecular interactions were determined by X-ray crystallographic techniques. The analysis of packing and interactions in the crystal lattice revealed that molecules in the target cocrystal were packed into tapes, formed by the O-H···O type contacts between the (-)-epicatechin and coformer molecules. The EC molecules interact with the carboxyl group in the BTA coformer mainly by -OH groups from the benzene ring A. The cocrystalline phase constituents were also investigated in terms of Hirshfeld surfaces. The application of Raman spectroscopy confirmed the involvement of the C=O group in the formation of hydrogen bonds between the (-)-epicatechin and barbituric acid molecules. Additionally, the solubility studies of pure EC and the EC-BTA cocrystal exhibited minor enhancement of EC solubility in the buffer solution, and pH measurements confirmed a stable level of solubility for EC and its cocrystal.

Engineering cocrystals of Paliperidone with enhanced solubility and dissolution characteristics

In the present study, co-crystals (CCs) of Paliperidone (PPD) with coformers like benzoic acid (BA) and P-amino benzoic acid (PABA) were synthesized and characterized to improve the physicochemical properties and dissolution rate. CCs were prepared by the solvent evaporation (SE) technique and were compared with the products formed by neat grinding (NG) and liquid assisted grinding (LAG) in their enhancement of solubility. The formation of CCs was confirmed by the IR spectroscopy, powder X-ray diffraction and thermal analysis methods. The saturation solubility studies indicate that the aqueous solubility of PPD-BA and PPD-PABA CCs was significantly improved to 1.343±0.162mg/ml and 1.964±0.452mg/ml, respectively, in comparison with the PPD solubility of 0.473mg/ml. This increase in solubility is 2.83-and 3.09-fold, respectively. PPD exhibited a poor dissolution of 37.8% in 60min, while the dissolution of the CCs improved tremendously to 96.07% and 89.65% in 60min. CCs of PPD with BA and PABA present a novel approach to overcome the solubility challenges of poorly water-soluble drug PPD.

Variable stoichiometry cocrystals: occurrence and significance

Stoichiometric variation in organic cocrystals, their synthesis, structure elucidation and properties are discussed. Accountable reasons for the occurrence of such cocrystals are emphasised.

Pharmaceutical cocrystal: a game changing approach for the administration of old drugs in new crystalline form

Pharmaceutical cocrystals are still gaining the interest of the researchers due to their potential to alter physicochemical, mechanical, and pharmacokinetic properties of active pharmaceutical ingredients without negotiating therapeutic action. The diverse new applications of cocrystals, like taste masking, reduced toxicity, patenting opportunities, commercial potential, etc. act as driving force to the rising interest of the pharmaceutical industries. Initially, cocrystals from the view of regulatory authorities, design strategies, cocrystal preparation in brief with special emphasis on scalable and solvent-free hot melt extrusion method, and practical guide to characterization have been provided. The special focus has been given to the biopharmaceutical attributes of the cocrystal. Finally, challenges before and after cocrystal preparation are presented in this review along with some commercial examples of the cocrystals.

Impact of Tablet Shape on Drug Dissolution Rate Through Immediate Released Tablets

Purpose: The aim of this study was to evaluate the influence of the geometric shape on the dissolution rate of the domperidone, a drug model for immediate release dosage form. In this regard, a lack of sufficient information about the effective dissolution rate of the drugs regarding their shapes has made this issue an interesting subject for researchers. Methods: For this purpose, three tablet shapes, namely flat and biconvex both in a round and oblong shapes, with different four sizes were modelled for the preparation of domperidone tablet. In vitro dissolution test was accomplished using a USP dissolution apparatus II. The drug dissolution rate was assessed by calculating various dissolution parameters; e.g., dissolution efficiency (DE), mean dissolution rate (MDR), mean dissolution time (MDT), and difference and similarity factors (f₁ and f₂ ). Results: Regarding the disintegration time, the larger tablets showed a faster disintegration time. When the size of the tablets was smaller, the amount of released drug was significantly decreased. In addition, #9 tablets with a flat or biconvex geometry had obvious effects on the DE values. Generally, biconvex tablets had higher DE percentage than the flat tablets. Conclusion: Noticeable differences in dissolution parameters by considering the different geometric shapes play an important role in the drug release kinetics which makes a significant effect on quick onset of action in oral administration.

Pharmaceutical Co-Crystallization: Regulatory Aspects, Design, Characterization, and Applications

Pharmaceutical co-crystals are novel class of pharmaceutical substances, which possess an apparent probability of advancement of polished physical properties offering stable and patentable solid forms. These multi-component crystalline forms influence pertinent physicochemical parameters like solubility, dissolution rate, chemical stability, physical stability, etc. which in turn result in the materials with superior properties to those of the free drug. Co-crystallization is a process by which the molecular interactions can be altered to optimize the drug properties. Co-crystals comprise a multicomponent system of active pharmaceutical ingredient (API) with a stoichiometric amount of a pharmaceutically acceptable coformer incorporated in the crystal lattice. By manufacturing pharmaceutical co-crystals, the physicochemical properties of a drug can be improved thus multicomponent crystalline materials have received renewed interest in the current scenario due to the easy administration in the pharmaceutical industry. There is an immense amount of literature available on co-crystals. However, there is a lack of an exhaustive review on a selection of coformers and regulations on co-crystals. The review has made an attempt to bridge this gap. The review also describes the methods used to prepare co-crystals with their characterization. Brief description on the pharmaceutical applications of co-crystals has also been incorporated here. Efforts are made to include reported works on co-crystals, which further help to understand the concept of co-crystals in depth.

Superior Solubility and Dissolution of Zaltoprofen via Pharmaceutical Cocrystals

Objectives

Pharmaceutical cocrystals are a promising tool to enhance the solubility and dissolution of poorly soluble drugs. Zaltoprofen (ZFN) is nonsteroidal anti-inflammatory drug with a prevalent solubility problem. The present study was undertaken to enhance the solubility and dissolution of ZFN through pharmaceutical cocrystals by screening various coformers.

Materials and Methods

Cocrystals of ZFN were prepared in 1:1 and 1:2 ratio of drug:coformer by the dry grinding method. The melting point and solubility of the crystalline phase were determined. The potential cocrystals were characterized by differential scanning calorimetry (DSC), infrared spectroscopy, and powder X-ray diffraction (PXRD). Cocrystals were subjected to dissolution rate and stability study.

Results

ZFN-nicotinamide (NIC) cocrystals demonstrated deviation in melting point and solubility. The cocrystals were obtained in both 1:1 and 1:2 ratios with NIC. The infrared analysis noticeably indicated the shifting of characteristic bands of ZFN. The crystallinity of the cocrystals was evident from the XRPD pattern and notable difference in the 2θ values of intense peaks. The DSC spectra of the cocrystals exhibited altered endotherms analogous to melting point. The cocrystals showed a faster dissolution rate and a 55% increase in the extent of dissolution compared to pure drug. The cocrystals were stable at room temperature and accelerated conditions.

Conclusion

The prepared cocrystals exhibited greater solubility and dissolution compared to the pure drug and were stable at room temperature and accelerated conditions.

Cocrystal Assembled by Pyrene Derivative and 1,4-Diiodotetrafluorobenzene via a C=O···I Halogen Bond

Cocrystal formation is a strategy used to modify the solid-state properties of a given molecule. In this study, a new cocrystal assembled by 1,4-Diiodotetrafluorobenzene (1,4-DITFB) and a pyrene derivative, 1-acetyl-3-phenyl-5-(1-pyrenyl)-pyrazoline (APPP), was synthesized. Due to the twisted structure of APPP, the crystal structure is greatly different with some large π-conjugated compounds, which exhibits edge-to-face π-stacked arrangement between 1,4-DITFB and pyrene rings, rather than the face-to-face π-stacked arrangement. Hirshfeld surface analysis and the shift of characteristic vibration band of the carbonyl group in FT-IR spectroscopy suggest the formation of a C=O···I halogen bond.

A Novel PAA Derivative with Enhanced Drug Efficacy in Pancreatic Cancer Cell Lines

Nanoparticles have been shown to be effective drug carriers in cancer therapy. Pancreatic cancer forms dense tumours which are often resistant to drug molecules. In order to overcome such multidrug resistance, new drug entities, novel delivery systems and combination therapy strategies are being explored. In this paper, we report the design and synthesis of a poly(allylamine)-based amphiphile modified with hydrophobic naphthalimido pendant groups. Bisnaphthalimide compounds have been shown to possess anticancer activity. The potential of this polymer to encapsulate, solubilize and enhance drug (5-fluorouricil and bis-(naphthalimidopropyl)-diaminooctane) cytotoxicity in BxPC-3 cells was evaluated. Our studies showed that the insoluble drugs could be formulated up to 4.3 mg mL-1 and 2.4 mg mL-1 inside the amphiphiles, respectively. Additionally, the novel poly(allylamine)-naphthalimide carrier resulted in an amplification of cytotoxic effect with drug treatment after 24 h, and was capable of reduction of 50% cell population at concentrations as low as 3 μg mL-1.