Aqueous Solubility Enhancement Through Engineering of Binary Solid Composites: Pharmaceutical Applications

Exploring Environmental Settings to Improve the Printability of Paroxetine-Loaded Filaments by Fused Deposition Modelling

The successful integration of hot-melt extrusion (HME) and fused deposition modelling (FDM) depends on a better understanding of the impact of environmental conditions on the printability of formulations, since they significantly affect the properties of the raw materials, whose control is crucial to enable three-dimensional printing (3DP). Hence, the objective of this work was to investigate the correlation between the environmental settings and the properties of paroxetine (PRX)-loaded filaments, previously produced by HME, which affect printability by FDM. The influence of different drying methods of the physical mixtures (PMs) and HME-filaments (FILs) on the quality and printability of these products was also assessed. The printability of FILs was evaluated in terms of the water content, and the mechanical and thermal properties of the products. Stability studies and physicochemical, thermal, and in vitro dissolution tests were carried out on the 3D-printed tablets. Stability studies demonstrated the high ductility of the PRX loaded FILs, especially under high humidity conditions. Under low humidity storage conditions (11% RH), the FILs became stiffer and were successfully used to feed the FDM printer. Water removal was slow when carried out passively in a controlled atmosphere (desiccator) or accelerated by using active drying methods (heat or microwave). Pre-drying of the PRX/excipients and/or PMs did not show any positive effect on the printability of the FIL. On the contrary, dry heat and, preferably, microwave mediated drying processes were shown to reduce the holding time required for successful FDM printing, enabling on-demand production at the point of care.

Evaluation of Piperine as Natural Coformer for Eutectics Preparation of Drugs Used in the Treatment of Cardiovascular Diseases

Piperine (PIP) was evaluated as a natural coformer in the preparation of multicomponent organic materials for enhancing solubility and dissolution rate of the poorly water-soluble drugs: curcumin (CUR), lovastatin (LOV), and irbesartan (IBS). A screening based on liquid assisted grinding technique was performed using 1:1 drug-PIP molar ratio mixtures, followed by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) analyses. Three eutectic mixtures (EMs) composed of CUR-PIP, LOV-PIP, and IBS-PIP were obtained. Therefore, binary phase and Tamman's diagrams were constructed for each system to obtain the exact eutectic composition, which was 0.41:0.59, 0.29:0.71, and 0.31:0.69 for CUR-PIP, LOV-PIP, and IBS-PIP, respectively. Further, bulk materials of each system were prepared to characterize them through DSC, PXRD fully, Fourier transform infrared spectroscopy (FT-IR), and solution-state nuclear magnetic resonance (NMR) spectroscopy. In addition, the contact angle, solubility, and dissolution rate of each system were evaluated. The preserved characteristic in the PXRD patterns and FT-IR spectra of the bulk material of each system confirmed the formation of EM mixture without molecular interaction in solid-state. The formation of EM resulted in improved aqueous solubility and dissolution rate associated with the increased wettability observed by the decrease in contact angle. In addition, solution NMR analyses of CUR-PIP, LOV-PIP, and IBS-PIP suggested no significant intermolecular interactions in solution between the components of the EM. Hence, this study concludes that PIP could be an effective coformer to improve the solubility and dissolution rate of CUR, LOV, and IBS.

Multicomponent Materials to Improve Solubility: Eutectics of Drug Aminoglutethimide

Here, we report the synthesis and experimental characterization of three drug-drug eutectic mixtures of drug aminoglutethimide (AMG) with caffeine (CAF), nicotinamide (NIC) and ethenzamide (ZMD). The eutectic mixtures i.e., AMG-CAF (1:0.4, molar ratio), AMG-NIC (1:1.9, molar ratio) and AMG-ZMD (1:1.4, molar ratio) demonstrate significant melting point depressions ranging from 99.2 to 127.2 °C compared to the melting point of the drug AMG (151 °C) and also show moderately higher aqueous solubilities than that of the AMG. The results presented include the determination of the binary melt phase diagrams and accompanying analytical characterization via X-ray powder diffraction, FT-IR spectroscopy and scanning electron microscopy.

Synthesis, Characterization, and Intrinsic Dissolution Studies of Drug-Drug Eutectic Solid Forms of Metformin Hydrochloride and Thiazide Diuretics

The mechanochemical synthesis of drug–drug solid forms containing metformin hydrochloride (MET·HCl) and thiazide diuretics hydrochlorothiazide (HTZ) or chlorothiazide (CTZ) is reported. Characterization of these new systems indicates formation of binary eutectic conglomerates, i.e., drug–drug eutectic solids (DDESs). Further analysis by construction of binary diagrams (DSC screening) exhibited the characteristic V-shaped form indicating formation of DDESs in both cases. These new DDESs were further characterized by different techniques, including thermal analysis (DSC), solid state NMR spectroscopy (SSNMR), powder X-ray diffraction (PXRD) and scanning electron microscopy–energy dispersive X-ray spectroscopy analysis (SEM–EDS). In addition, intrinsic dissolution rate experiments and solubility assays were performed. In the case of MET·HCl-HTZ (χ_MET·HCl = 0.66), we observed a slight enhancement in the dissolution properties compared with pure HTZ (1.21-fold). The same analysis for the solid forms of MET·HCl-CTZ (χ_MET·HCl = 0.33 and 0.5) showed an enhancement in the dissolved amount of CTZ accompanied by a slight improvement in solubility. From these dissolution profiles and saturation solubility studies and by comparing the thermodynamic parameters (ΔH_fus and ΔS_fus) of the pure drugs with these new solid forms, it can be observed that there was a limited modification in these properties, not modifying the free energy of the solution (ΔG) and thus not allowing an improvement in the dissolution and solubility properties of these solid forms.

Performance and paroxetine stability in tablets manufactured by fused deposition modelling-based 3D printing

OBJECTIVES

The objective of this study was to develop a method for the preparation and characterization of paroxetine (PRX) tablets, obtained by coupling hot-melt extrusion and fused deposition modelling (FDM)-based three-dimensional printing (3DP) technology. The impact of the printing process parameters on the drug stability and on the tablets performance was assessed.

METHODS

Tablets were obtained by FDM of hot-melt extruded PRX-loaded filaments. Physicochemical, thermal, spectroscopic, diffractometric analysis and in-vitro dissolution tests of the intermediate products and the finished dosage forms were performed.

KEY FINDINGS

The characterization of printed tablets evidenced mass and dimensions uniformity, and consistency of drug content and dissolution profile. The formation of amorphous solid dispersions and interaction of formulation components throughout the manufacturing process were demonstrated. Layer thickness, printing temperature, printing and travelling speeds, and infill were the most impacting process parameters on both the physicochemical properties and the in-vitro performance of the 3D-printed tablets.

CONCLUSIONS

PRX tablets, meeting compendial limits, were manufactured by 3DP, envisaging their clinical use as individually designed dosage forms. The assessment of the impact of processing parameters on the printed tablets provided insights, which will ultimately allow streamlining of the 3D process set-up for quicker and easier production of patient-centric medicines.

Ternary Eutectic Ezetimibe-Simvastatin-Fenofibrate System and the Physical Stability of Its Amorphous Form

In this study, the phase diagram of the ternary system of ezetimibe–simvastatin–fenofibrate was established. It has been proven that the ternary composition recommended for the treatment of mixed hyperlipidemia forms a eutectic system. Since eutectic mixtures are characterized by greater solubility and dissolution rate, the obtained result can explain the marvelous medical effectiveness of combined therapy. Considering that another well-known method for improving the aqueous solubility is amorphization, the ternary system with eutectic concentration was converted into an amorphous form. Thermal properties, molecular dynamics, and physical stability of the obtained amorphous system were thoroughly investigated through various experimental techniques compared to both: neat amorphous active pharmaceutical ingredients (considered separately) and other representative concentrations of ternary mixture. The obtained results open up a new way of selecting the therapeutic concentrations for combined therapies, a path that considers one additional variable: eutecticity.

Eutectic mixtures as an approach to enhance solubility, dissolution rate and oral bioavailability of poorly water-soluble drugs

Eutectic mixtures have been known for a long time in the pharmaceutical field. However, its potential as a system to improve the solubility and dissolution of poorly water-soluble drugs remains little explored. Studies involving the microstructural characterization and the preparation of solid dosage forms containing eutectic mixtures are also an issue to be developed. Recently, the number of studies involving the preparation of eutectic mixtures to improve the solubility and oral bioavailability of poorly soluble drugs has increased considerably, including drug-carrier and drug-drug mixtures. In this review is discussed the potential of eutectic mixtures as an alternative pharmaceutical solid system to enhance drugs solubility, dissolution rate or oral bioavailability. Different aspects like history, physico-chemical, microstructural properties, preparation methods, mechanisms involved in solubility/dissolution enhancement, techniques for solid state characterization, in vivo studies, advantages, limitations and formulation perspective are also discussed.

Determination of Stable Co-Amorphous Drug-Drug Ratios from the Eutectic Behavior of Crystalline Physical Mixtures

Co-amorphous drug–drug systems have been developed with the overall aim of improving the physical stability of two or more amorphous drugs. Co-amorphous systems often show good physical stability, and higher solubility and dissolution rates compared to their crystalline counterparts. The aim of this study is to determine if eutectic mixtures of two drugs can form stable co-amorphous systems. Three drug–drug mixtures, indomethacin–naproxen (IND−NAP), nifedipine–paracetamol (NIF−PAR), and paracetamol–celecoxib (PAR−CCX), were investigated for their eutectic and co-amorphization behavior as well as their physical stability in the co-amorphous form. The phase diagrams of the crystalline mixtures and the thermal behavior of the co-amorphous systems were analyzed by differential scanning calorimetry. The solid-state form and physical stability of the co-amorphous systems were analyzed using X-ray powder diffractometry during storage at room temperature at dry conditions. Initial eutectic screening using nifedipine (NIF), paracetamol (PAR), and celecoxib (CCX) indicated that IND−NAP, NIF−PAR, and PAR−CCX can form eutectic mixtures. Phase diagrams were then constructed using theoretical and experimental values. These systems, at different drug-to-drug ratios, were melted and cooled to form binary mixtures. Most mixtures were found to be co-amorphous systems, as they were amorphous and exhibited a single glass transition temperature. The stability study of the co-amorphous systems indicated differences in their physical stability. Comparing the phase diagrams with the physical stability of the co-amorphous mixtures, it was evident that the respective drug–drug ratio that forms the eutectic point also forms the most stable co-amorphous system. The eutectic behavior of drug–drug systems can thus be used to predict drug ratios that form the most stable co-amorphous systems.

Role of Structure, Microenvironmental pH, and Speciation To Understand the Formation and Properties of Febuxostat Eutectics

Cocrystallization studies were undertaken to improve the solubility of a highly water-insoluble drug, febuxostat (FXT), used in the treatment of gout and hyperuricemia. A liquid-assisted grinding (LAG) method was successfully employed, starting with the screening of various coformers for obtaining cocrystals. However, in this process, three eutectic systems with coformers (probenecid, adipic acid, and α-ketoglutaric acid) were formed. Affinities of the different functional groups to form a hydrogen bond and ΔpK_a differences, leading to the eutectic formation, were discussed. The eutectic systems thus formed were further characterized and analyzed using a differential scanning calorimeter (DSC) and powder X-ray diffraction (PXRD). Binary thermal phase diagrams were plotted using different ratios of the systems to confirm the formation of eutectics, and pH-dependent solubility studies exhibited a significant decrease in the solubility in comparison to that of the drug for all three eutectic systems. The solubility of FXT reduced from 46.53 μg/mL (pH 5.63) to 46.03 μg/mL, 28.53 μg/mL, and 18.88 μg/mL; 770.58 μg/mL (pH 8.21) to 307.574 μg/mL, 116.63 μg/mL, 113.40 μg/mL; and from 13165.97 μg/mL (pH 10.13) to 1409.737 μg/mL, 854.51 μg/mL, and 1218.99 μg/mL for FXT-probenecid, FXT-adipic acid, and FXT-α-ketoglutaric acid eutectic systems, respectively. Furthermore, the microenvironmental pH studies were carried out to understand the effect of the microenvironment on the solubility of these eutectic systems. The contribution to solubility from lattice and nonlattice forces considering the microenvironment was also discussed.

What if Cocrystallization Fails for Neutral Molecules? Screening Offered Eutectics as Alternate Pharmaceutical Materials: Leflunomide-a Case Study

Background: The manuscript is aimed to optimize the biopharmaceutical parameters of a poorly soluble, neutral anti-rheumatic drug ‘leflunomide’ by preparing its non-covalent derivatives (NCDs). For this various monocarboxylic acids- (adipic acid, picolinic acid) and dicarboxylic acids (maleic acid, malonic acid, sorbic acid), as well as pyridine carboxamide derivatives (nicotinamide, isonicotinamide), are used as coformers. Methods: The novel solid forms were rationally prepared and systematically characterized. Further, these solid forms were subjected to equilibrium solubility and intrinsic dissolution rate (IDR) analysis in three aqueous media (pH 1.2, pH 4.5 and pH 6.8). In vivo plasma studies in male Wistar rats were done to assess the effect on area under the curve (AUC) and the maximum concentration (Cmax) of leflunomide in prepared solid forms. Results: These NCD were primarily characterized to be eutectics rather than cocrystals as expected. The stoichiometry was established by phase diagrams. The negative value of heat of mixing indicated them to be of cluster type. In addition, leflunomide in eutectics showed approximately 9 folds increase in solubility up to 4 hours. Besides this, approximately 4 folds enhancement in the in IDR was also observed. Maximum increase in bioavailability indicated by enhanced values of AUC and Cmax (490.29 μg h-1 mL-1 and 31.42 μg mL-1, respectively) for leflunomide-maleic acid eutectic in comparison to pure LEF (AUC: 193.20 μg h-1 mL-1 and Cmax: 12.09 μg mL-1). Conclusion: The unsuccessful cocrystallization experiments were found be the latent eutectics. The evaluation of these novel eutectics of poorly soluble drug exhibited possibility to further amplify the scope of accessible material phase options other than pure active pharmaceutical ingredient (API) without disturbing the structural integrity.

A novel approach to design febuxostat-salicylic acid eutectic system: evaluation and characterization

The current study was aimed at investigating the febuxostat-salicylic acid (FXT-SAA) eutectic system using two polymorphs of FXT, form Q and form A.

Revealing the Role of Structural Features in Bulk Mechanical Performance of Ternary Molecular Solids of Isoniazid

Mechanical performance in ternary (3n) molecular solids has been rarely studied, and hence it is an interesting topic of investigation in the direct compression method of tableting. The structural features of 3n-eutectic (3n-Eu: INZ-ADP-NIC) and 3n-cocrystal (3n-Co: INZ:SUC:NIC) were explored to understand the bonding area-bonding strength (BA-BS) interplay. Higher compressibility and lower values of the Heckel parameter of 3n-Co as compared to 3n-Eu suggested its better deformation behavior, with BA being the predominant factor. The higher tensile strength and Walker analysis indicated a higher compressibility coefficient ( W) and lower pressing modulus ( L) for 3n-Eu, which was consistent with its better tabletability over 3n-Co. The higher compressibility and plastic energy, and higher value of L of 3n-Co, were attributed to the facile propagation (⟨-1' 0' 5'⟩) of the shearing molecular slip (-1 0 5) when subjected to the external mechanical stress. Thus, the overall higher tableting performance of 3n-Eu over 3n-Co was found due to the predominant BS and limited contribution of BA. The latter was the dominant factor in 3n-Co. Cohesive interactions, like the 3D mechanically interlocked structure of conglomerates of 3n-Eu, contributed toward the higher BS. Moreover, the prediction of better tabletability solely based on crystallographic feature slip planes (0D/1D/2D H-bonded layer (h k l) ⊥ vdW interactions) is warranted in pharmaceutical molecular solids. Eutectics with varying microstructural variants ( nL_α + nL_β + nL_γ) may open up the opportunity to manipulate the physicomechanical performance.

Is Failure of Cocrystallization Actually a Failure? Eutectic Formation in Cocrystal Screening of Hesperetin

Cocrystal screening of hesperetin with certain countermolecules generated highly soluble noncovalent derivatives in the form of eutectics, instead of expected cocrystals. As adhesive forces established by complimentary functional groups on hesperetin and coformers were unable to overcome the stress due to size shape mismatch of component molecules, thus, eutectics were formed. Hesperetin, a polyphenolic antioxidant with potent anticancer and cardioprotective effects, has an underdeveloped role in modern therapeutics on account of its critically low aqueous solubility resulting in stunted bioavailability. The liquid-assisted cogrinding of hesperetin and coformers generated binary-phase eutectics in fixed stoichiometry with theophylline (1:1.5), adenine (2:1), gallic acid (1.5:1), and theobromine (2:1). Primarily characterized by lower melting endotherm in differential scanning calorimetry, the eutectics showed complete melting in hot-stage microscopy. Apart from characteristic V-shaped binary-phase diagram, no discernible changes in the FTIR and powder X-ray diffraction spectra further confirm eutectic formation. The morphological differences were analyzed by SEM measurements. A 2 to 4 times enhanced dissolution profile of the eutectics measured in pH 7.4 aqueous buffer was coupled with the in vitro (1,1-diphenyl-2-picryl hydroxyl free radical antioxidant assay and RBC antihemolytic assay) studies to present a complete preliminary data on the improved bioavailability of hesperetin eutectics.

Influence of the cooling rate and the blend ratio on the physical stability of co-amorphous naproxen/indomethacin

Co-amorphization represents a promising approach to increase the physical stability and dissolution rate of amorphous active pharmaceutical ingredients (APIs) as an alternative to polymer glass solutions. For amorphous and co-amorphous systems, it is reported that the preparation method and the blend ratio play major roles with regard to the resulting physical stability. Therefore, in the present study, co-amorphous naproxen-indomethacin (NAP/IND) was prepared by melt-quenching at three different cooling rates and at ten different NAP/IND blend ratios. The samples were analyzed using XRPD and FTIR, both directly after preparation and during storage to investigate their physical stabilities. All cooling methods led to fully amorphous samples, but with significantly different physical stabilities. Samples prepared by fast cooling had a higher degree of crystallinity after 300d of storage than samples prepared by intermediate cooling and slow cooling. Intermediate cooling was subsequently used to prepare co-amorphous NAP/IND at different blend ratios. In a previous study, it was postulated that the equimolar (0.5:0.5) co-amorphous blend of NAP/IND is most stable. However, in the present study the physically most stable blend was found for a NAP/IND ratio of 0.6:0.4, which also represents the eutectic composition of the crystalline NAP/γ-IND system. This indicates that the eutectic point may be of major importance for the stability of binary co-amorphous systems. Slight deviations from the optimal naproxen molar fraction led to significant recrystallization during storage. Either naproxen or γ-indomethacin recrystallized until a naproxen molar fraction of about 0.6 in the residual co-amorphous phase was reached again. In conclusion, the physical stability of co-amorphous NAP/IND may be significantly improved, if suitable preparation conditions and the optimal phase composition are chosen.

The role of the carrier in the formulation of pharmaceutical solid dispersions. Part I: crystalline and semi-crystalline carriers

INTRODUCTION

As a consequence of the target and drug candidate identification process, drugs with higher hydrophobicity and/or lipophilicity are being selected for further development, leading to solubility and dissolution rate limited oral bioavailability, and hence potential failure of the intended therapeutic goal. Solid dispersions were introduced as a formulation strategy in the early 1960s to tackle this issue and are still an area of intensive research activity. Areas covered: There has been a shift in the type of carriers that were used in the formulation of solid dispersions as nowadays, amorphous carriers are most often used, whereas in early stages of solid dispersions development, crystalline and semi-crystalline carriers were most commonly applied. In this review, we will discuss several aspects related to the use of crystalline and semi-crystalline carriers such as their molecular and related physical structure, and their physical chemical properties related to formulation of poorly soluble drugs. Expert opinion: The inherent crystallinity of this type of carrier hinders the formation of high-load solid solutions as mainly the amorphous domains of a carrier are able to accommodate drug molecules. Hence these carriers are not currently first choice excipients to formulate solid dispersions.

Non-Covalent Derivatives: Cocrystals and Eutectics

Non-covalent derivatives (NCDs) are formed by incorporating one (or more) coformer molecule(s) into the matrix of a parent molecule via non-covalent forces. These forces can include ionic forces, Van der Waals forces, hydrogen bonding, lipophilic-lipophilic interactions and pi-pi interactions. NCDs, in both cocrystal and eutectic forms, possess properties that are unique to their supramolecular matrix. These properties include critical product performance factors such as solubility, stability and bioavailability. NCDs have been used to tailor materials for a variety of applications and have the potential to be used in an even broader range of materials and processes. NCDs can be prepared using little or no solvent and none of the reagents typical to synthetic modifications. Thus, NCDs represent a powerfully versatile, environmentally-friendly and cost-effective opportunity.

Do carboximide-carboxylic acid combinations form co-crystals? The role of hydroxyl substitution on the formation of co-crystals and eutectics

Carboxylic acids, amides and imides are key organic systems which provide understanding of molecular recognition and binding phenomena important in biological and pharmaceutical settings. In this context, studies of their mutual interactions and compatibility through co-crystallization may pave the way for greater understanding and new applications of their combinations. Extensive co-crystallization studies are available for carboxylic acid/amide combinations, but only a few examples of carboxylic acid/imide co-crystals are currently observed in the literature. The non-formation of co-crystals for carboxylic acid/imide combinations has previously been rationalized, based on steric and computed stability factors. In the light of the growing awareness of eutectic mixtures as an alternative outcome in co-crystallization experiments, the nature of various benzoic acid/cyclic imide combinations is established in this paper. Since an additional functional group can provide sites for new intermolecular inter-actions and, potentially, promote supramolecular growth into a co-crystal, benzoic acids decorated with one or more hydroxyl groups have been systematically screened for co-crystallization with one unsaturated and two saturated cyclic imides. The facile formation of an abundant number of hydroxybenzoic acid/cyclic carboximide co-crystals is reported, including polymorphic and variable stoichiometry co-crystals. In the cases where co-crystals did not form, the combinations are shown invariably to result in eutectics. The presence or absence and geometric disposition of hydroxyl functionality on benzoic acid is thus found to drive the formation of co-crystals or eutectics for the studied carboxylic acid/imide combinations.

Eutectics as improved pharmaceutical materials: design, properties and characterization

Eutectics are a long known class of multi-component solids with important and useful applications in daily life. In comparison to other multi-component crystalline solids, such as salts, solid solutions, molecular complexes and cocrystals, eutectics are less studied in terms of molecular structure organization and bonding interactions. Classically, a eutectic is defined based on its low melting point compared to the individual components. In this article, we attempt to define eutectics not just based on thermal methods but from a structural organization view point, and discuss their microstructures and properties as organic materials vis-a-vis solid solutions and cocrystals. The X-ray crystal structure of a cocrystal is different from that of the individual components whereas the unit cell of a solid solution is similar to that of one of the components. Eutectics are closer to the latter species in that their crystalline arrangement is similar to the parent components but they are different with respect to the structural integrity. A solid solution possesses structural homogeneity throughout the structure (single phase) but a eutectic is a heterogeneous ensemble of individual components whose crystal structures are like discontinuous solid solutions (phase separated). Thus, a eutectic may be better defined as a conglomerate of solid solutions. A structural analysis of cocrystals, solid solutions and eutectics has led to an understanding that materials with strong adhesive (hetero) interactions between the unlike components will lead to cocrystals whereas those having stronger cohesive (homo/self) interactions will more often give rise to solid solutions (for similar structures of components) and eutectics (for different structures of components). We demonstrate that the same crystal engineering principles which have been profitably utilized for cocrystal design in the past decade can now be applied to make eutectics as novel composite materials, illustrated by stable eutectics of the hygroscopic salt of the anti-tuberculosis drug ethambutol as a case study. A current gap in the characterization of eutectic microstructure may be fulfilled through pair distribution function (PDF) analysis of X-ray diffraction data, which could be a rapid signature technique to differentiate eutectics from their components.

Implication of microstructure on the mechanical behaviour of an aspirin–paracetamol eutectic mixture

The present work investigates the mechanical behaviour of an aspirin–paracetamol (ASP–PCM) eutectic mixture (EM).

Liquid antisolvent precipitation process for solubility modulation of bicalutamide

Liquid antisolvent process was explored as a solubility modulating tool. Bicalutamide, a poorly water soluble drug, was used as a candidate. Low aqueous solubility and poor dissolution of bicalutamide results into poor and variable bioavailability. Therefore, the objective of the present work was to modify the solubility of bicalutamide using the liquid antisolvent precipitation process. HPMC E5 and Poloxamer 407 were shortlisted as a hydrophilic polymer and surfactant, respectively, for the process. Process optimization was done with respect to the hydrophilic polymer, surfactant and drug loading concentration. The resultant microcrystals were characterized with various instrumental techniques for material characterization such as IR, DSC, SEM, XRD, particle size, specific surface area and dissolution kinetics.