Physicochemical characterization and dissolution properties of nimesulide-cyclodextrin binary systems

Thermal stability of amorphous nimesulide: from glass formation to crystal growth and thermal degradation

Thermally induced physico-chemical transformations in amorphous nimesulide were studied by means of differential scanning calorimetry (DSC), thermogravimetry, and Raman microscopy. The equilibrium glass transition temperature was found to be Tg0 = 10-15 °C, and the relaxation motions were found to be temperature-dependent. Crystal growth from the amorphous phase was found to be crucially dependent on the presence of mechanical defects that serve as centers for heterogeneous nucleation. The large amounts of mechanical defects significantly decrease the activation energy of the macroscopic crystallization; the positions of the crystallization peaks and their asymmetry/shape remain however almost unchanged. At laboratory temperature, powdered nimesulide fully crystallizes within several hours, with an absolute majority of the crystalline phase being formed as the thermodynamically stable form I polymorph. Amorphous nimesulide does not crystallize from the free smooth surface (no trace of formed crystallites was found by optical microscopy after 30 days at laboratory temperature). Nimesulide was found to be very stable at temperatures above its melting point of 147.5 °C; thermal degradation starts to proceed slowly at 200 °C. Mutual correlations between the macroscopic and microscopic crystal growth processes and between the viscous flow and structural relaxation motions were discussed based on the values of the corresponding activation energies. A link between the cooperativity of structural domains, parameters of the Tool-Narayanaswamy-Moynihan relaxation model, and microscopic crystal growth was proposed.

Development and Evaluation of Cocoa Butter Taste Masked Ibuprofen Using Supercritical Carbon Dioxide

Masking the unpleasant taste of the pharmaceutically active ingredients plays a critical role in patient acceptance, particularly for children. This work's primary objective was the preparation of taste-masked ibuprofen microparticles using cocoa butter with the assistance of supercritical fluid technology. Microparticles were prepared by dissolving ibuprofen in melted cocoa butter at 40 °C. The solution was then introduced into a supercritical fluid unit and processed at 10 MPa CO₂ pressure for 30 min. The product was collected after depressurizing the system. The effect of the drug to cocoa butter ratio and the supercritical fluid units' configuration on product quality was evaluated and compared with the sample prepared by a conventional method. Physicochemical characterization of the prepared product, including particle size, crystallinity, entrapment efficiency, in vitro drug release, and product taste using a human volunteer panel was conducted. The produced microparticles were in the range of 1.42 to 15.28 μm. The entrapment efficiency of the formulated microparticles ranged from 66 to 81%. The drug:polymer ratio, the configuration of the supercritical fluid unit, and the method of preparation were found to have a critical role in the formulation of ibuprofen microparticles. Taste evaluation using human volunteers showed that microparticles containing 20% drug and processed with supercritical fluid technology were capable of masking the bitter taste of ibuprofen. In conclusion, the dispersion of ibuprofen in cocoa butter using supercritical fluid technology is a a promising innovative method to mask the bitter taste of ibuprofen.

Solubility Enhancement of Atrazine by Complexation with Cyclosophoraose Isolated from Rhizobium leguminosarum biovar trifolii TA-1

Rhizobium leguminosarum biovar trifolii TA-1, a kind of soil bacteria, produces cyclosophoraoses (Cys). Cyclosophoraoses contain various ring sizes with degrees of polymerization ranging from 17 to 23. Atrazine is a hardly-soluble herbicide that contaminates soil and drinking water, and remains in soil for a long time. To remove this insoluble contaminant from aqueous solutions, we have enhanced the solubility of atrazine by complexation with Cys. The complex formation of Cys and atrazine was confirmed using ¹H nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), field emission scanning electron microscopy (FE-SEM), rotating frame nuclear overhauser spectroscopy (ROESY), and molecular modeling studies. The aqueous solubility of atrazine was enhanced 3.69-fold according to the added concentrations (20 mM) of Cys, compared to the 1.78-fold enhancements by β-cyclodextrin (β-CD). Cyclosophoraoses as an excellent solubility enhancer with long glucose chains that can effectively capture insoluble materials showed a potential application of microbial polysaccharides in the removal of hazardous hardly-soluble materials from aqueous solutions in the fields of biological and environmental industry.

Characterization of the Dissolution Behavior of Piperine/Cyclodextrins Inclusion Complexes

In this study, the physicochemical properties and solubility of inclusion complexes of ground mixtures (GMs) of piperine (PP), a pungent ingredient of pepper, with α- and γ-cyclodextrin (CD) were studied. From the solubility results, the PP/αCD inclusion molar ratio was determined to be 1/2, while that of PP/γCD was 1/1, according to the A_P-type phase diagram of PP/αCD and the B_S-type one of PP/γCD. The powder X-ray diffraction and differential scanning calorimetry analyses confirmed the formation of GM complexes with molar ratios of PP/αCD = 1/2 and PP/γCD = 1/1. The Raman analysis revealed the disappearance of the bands corresponding to the C=C, O-CH₂-O, -CH, and aliphatic C=C moieties of the methylene dioxyphenyl fragment of PP in the spectra of the inclusion complexes. In the dissolution tests, GM (PP/αCD = 1/2) and GM (PP/γCD = 1/1) showed higher solubility than free PP and the analogous physical mixtures. Furthermore, after 60 min, GM (PP/αCD = 1/2) exhibited higher solubility than GM (PP/γCD = 1/1). In the ¹H-¹H nuclear Overhauser effect spectroscopy measurements, GM (PP/αCD = 1/2) was found to present a head-to-head inclusion structure via the aliphatic C=C and methylene dioxyphenyl groups of PP and the two αCD molecules. In contrast, it was confirmed that γCD interacts with the O-CH₂-O functionality of the methylene dioxyphenyl group of PP in a molar ratio of 1/1. It was thus concluded that the differences in the PP/CD structures influence the solubility of the inclusion complexes.

Host-guest interactions between sildenafil and cyclodextrins: Spectrofluorometric study and molecular dynamic modeling

Sildenafil (SF) was included in cyclodextrins (CD) to enhance its solubility. Spectrofluorometry was used to confirm the complexation constant (stability constant). The orientations of SF inside the β-CDs and γ-CDs were fully illustrated. Molecular dynamics simulations were performed on two inclusion complexes (β-CD/SF and γ-CD/SF) in the aqueous system. The polar methylpiperazine group was found to locate inside the β-CD cavity, both in the wide and narrow side and was positioned 2°A from the center. In contrast, the methylpiperazine group did not fit well within the γ-CD cavity. Moreover, these results also confirmed hydrogen bonding that the highest number of bonding formed between the polar methylpiperazine sulfonyl structure and the hydroxyl group of β-CD. The simulated binding free energy of the methylpiperazine-β-CD inclusion complex (-6.01kcal/mol), featured a large contribution from electrostatic and van der Waals forces, which was the most stable complex. The association constant of β-CD/SF (12.3) was higher than γ-CD/SF (3.3) and confirmed with in silico measurements of binding free energy. In summary, SF forms a stable complex with β-CD.

Improving cyclodextrin complexation of a new antihepatitis drug with glacial acetic acid

The purpose of this study was to develop and evaluate a solid nonaqueous oral dosage form for a new hepatitis C drug, PG301029, which is insoluble and unstable in water. Hydroxypropyl-β-cyclodextrin (HPβCD) and PG301029 were dissolved in glacial acetic acid. The acetic acid was removed by rotoevaporation such that the drug exists primarily in the complexed form. The stability of formulated PG301029 was determined upon dry storage and after reconstitution in simulated intestinal fluid (SIF), simulated gastric fluid (SGF), and water. Formulated PG301029 was found to be stable upon storage and can be reconstituted with water to a concentration 200 times that of the intrinsic solubility. Once reconstituted, the powder dissolves rapidly and PG301029 remains stable for 21 hours in SGF, SIF, and water. The unique use of acetic acid and HPβCD results in a solid dosage form of PG301029 that is both soluble and stable in water.

γ-Cyclodextrin

γ-Cyclodextrin (γCD) is a cyclic oligosaccharide formed by bacterial digestion of starch and used as solubilizing agent and stabilizer in a variety of pharmaceutical and food products. γCD is a large (molecular weight 1297Da) hydrophilic molecule that does not readily permeate biological membranes and is rapidly digested by bacteria in the gastrointestinal tract. In humans γCD is metabolized by α-amylase that is found in, for example, saliva, bile fluid and tears. Thus, bioavailability of γCD is negligible. Also, γCD is readily excreted unchanged in the urine after parenteral administration. Like other cyclodextrins, γCD can form water-soluble inclusion complexes with many poorly-soluble compounds. In comparison with the natural αCD and βCD, γCD has the largest hydrophobic cavity, highest water solubility and the most favorable toxicological profile. The focus of this review is production, physiochemical properties, pharmacokinetics, toxicity and applications of γCD and its derivatives. Also, the aggregation behavior of γCD in aqueous media is discussed.

Effect of Poloxamer on release of poorly water soluble drug Loratadine from solid dispersion: Kneading method

The main objective of the current study was to enhance the solubility and dissolution of poorly water soluble drug Loratadine (LOR) through formulation of solid dispersion systems (SDs) using hydrophilic polymers. SDs were prepared by kneading method using different drug-to-polymer ratios (1:3 and 1:5) with poloxomer 188 (samples DS1, DS2) and poloxomer 407 (samples DS3, DS4) as hydrophilic polymers. In vitro drug release studies were performed on prepared SDs (DS1-DS4) and compared to pure drug (LOR only, sample DS0). Prepared SDs showed significant improvement in the release profile compared to LOR.

Formulation and optimization of nonionic surfactants emulsified nimesulide-loaded PLGA-based nanoparticles by design of experiments

This investigation aimed to develop nimesulide (NMS)-loaded poly(lactic-co-glycolic acid) (PLGA)-based nanoparticulate formulations as a biodegradable polymeric drug carrier to treat rheumatoid arthritis. Polymeric nanoparticles (NPs) were prepared with two different nonionic surfactants, vitamin E d-α-tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS) and poly(vinyl alcohol) (PVA), using an ultrasonication solvent evaporation technique. Nine batches were formulated for each surfactant using a 3(2) factorial design for optimal concentration of the emulsifying agents, 0.03-0.09% for vitamin E TPGS and 2-4% for PVA. The surfactant percentage and the drug/polymer ratio (1:10, 1:15, 1:20) of the NMS-loaded NPs were investigated based on four responses: encapsulation efficiency, particle size, the polydispersity index, and the surface charge. The response surface plots and linearity curves indicated a relationship between the experiment's responses and a set of independent variables. The NPs produced with both surfactants exhibited a negative surface charge, and scanning electron micrographs revealed that all of the NPs were spherical in shape. A narrower size distribution and higher drug loadings were achieved in PVA-emulsified PLGA NPs than in the vitamin E TPGS emulsified. Decreasing amounts of both nonionic surfactants resulted in a reduction in the emulsion's viscosity, which led to a decrease in the particle size of NPs. According to the ANOVA results obtained in this present research, vitamin E TPGS exhibited the best correlation between the independent variables, namely drug/polymer ratio and the surfactant percentage, and the dependent variables (encapsulation efficiency R(2) = 0.9603, particle size R(2) = 0.9965, size distribution R(2) = 0.9899, and surface charge R(2) = 0.8969) compared with PVA.

Development and validation of a dissolution test for meloxicam and pridinol mesylate from combined tablet formulation

The association of meloxicam and pridinol is indicated for treating muscular contractures and low back pain. A dissolution test for the meloxicam-pridinol combined tablet formulation was developed and validated, using a suitable HPLC method for simultaneously quantitating both dissolved drugs. The optimized conditions include the use of USP apparatus 2 at a paddle rotation rate of 75 rpm and 900 ml of 50 mM phosphate buffer (pH= 7.5) as dissolution medium, at 37.0±0.5°. The test, which demonstrated to be robust against small changes in bath temperature, paddle rotation speed and pH of the dissolution medium, was applied to two different brands of tablets; the corresponding dissolution profiles were constructed and both brands showed to dissolve at least 75% of the drugs at the 45 min time point.

Effect of auxiliary substances on complexation efficiency and intrinsic dissolution rate of gemfibrozil-beta-CD complexes

The studies reported in this work are aimed to elucidate the ternary inclusion complex formation of gemfibrozil (GFZ), a poorly water-soluble drug, with beta-cyclodextrin (beta-CD) with the aid of auxiliary substances like different grades of povidone(s) (viz. PVP K-29/32, PVP K-40, Plasdone S-630, and Polyplasdone XL), organic base (viz. triethanolamine), and metal ion (viz. MgCl(2).6H(2)O), by investigating their interactions in solution and solid state. Phase solubility studies were carried out to evaluate the solubilizing power of beta-cyclodextrin, in association with various auxiliary substances, to determine the apparent stability constant (K (C)) and complexation efficiency (CE) of complexes. Improvement in K (C) values for ternary complexes clearly proves the benefit of the addition of auxiliary substances to promote CE. Of all the approaches used, the use of polymer Plasdone S-630 was found to be the most promising approach in terms of optimum CE and K (C). GFZ-beta-CD (1:1) binary and ternary systems were prepared by kneading and lyophilization methods. The ternary systems clearly signified superiority over binary systems in terms of CE, solubility, K (C), and reduction in the formulation bulk. Optimized ternary system of GFZ-beta-CD-Plasdone S-630 prepared by using lyophilization method indicated a significant improvement in intrinsic dissolution rate when compared with ternary kneaded system. Differential scanning calorimetry, X-ray diffraction, Fourier transform infrared, scanning electron microscopy, and proton nuclear magnetic resonance were carried out to characterize the binary and optimized ternary complex. The results suggested the formation of new solid phases, eliciting strong evidences of ternary inclusion complex formation between GFZ, beta-CD, and Plasdone S-630, particularly for lyophilized products.

Effect of pH and water-soluble polymers on the aqueous solubility of nimesulide in the absence and presence of β-cyclodextrin derivatives

The aqueous solubility of nimesulide in the absence and presence of β-cyclodextrin (β-CD) and its alkyl derivatives hydroxypropyl-β-CD and methyl-β-CD was studied. We also investigated the effect of water-soluble polymers, hydroxypropylmethyl-cellulose, sodium-carboxymethyl-cellulose, polyvinyl- pyrrolidone and polyethyleneglycol on the solubilization efficacy and complexation ability of cyclodextrins with nimesulide. The solubility of nimesulide in the absence and presence of cyclodextrins and polymers was studied using a phase solubility technique combined with a spectrophotometric method. The study was carried out at 25°C and pH values of 6.0 and 7.0. Conditions in terms of polymer concentration and polymer heating with and without sonication were optimized. Values of the solubility enhancement factor of nimesulide in the presence of each cyclodextrin and in the absence and presence of each polymer were determined and the formation constants, K, of the inclusion complexes formed calculated. β-CDs increased the aqueous solubility of nimesulide in the following order: methyl-β-CD > β-CD > hydroxypropyl-β-CD. Addition of hydroxypropylmethyl-cellulose at a concentration of 0.1% (w/v) had the greatest influence on complexation of all three β-CDs with nimesulide, while preheating of the polymer at 70°C under sonication resulted in an additional two-fold increase in the aqueous solubility of the drug. Sodium- carboxymethyl-cellulose, polyvinylpyrrolidone and polyethyleneglycol had minor effects on the aqueous solubility of nimesulide. Thus β-CD, hydroxypropyl-β-CD and methyl-β-CD are proposed as good solubilizing agents for nimesulide in the presence and absence of hydroxypropylmethyl- cellulose in order to enhance its oral bioavailability.

Study of nimesulide release from solid pharmaceutical formulations in tween 80 solutions

Nimesulide is a weakly acidic non-steroidal anti-inflammatory drug (NSAIDs). Like many non-steroidal anti-inflammatory drugs, Nimesulide is very sparingly soluble in water (≈ 0.01 mg/mL).The poor aqueous solubility and wettability of Nimesulide gives rise to difficulties in pharmaceutical formulations for oral or parenteral delivery, which may lead to variable bioavailability. Based on the Biopharmaceutical Classification System (BCS), Nimesulide is considered a BCS 2 drug (poorly soluble and highly permeable). Solubilization in surfactant solutions above critical micelle concentration (CMC) offers one approach to the formulation of poorly soluble drugs. Weakly acidic and basic drugs may be brought into solution by the solubilizing action of surfactants. In this study, different concentrations of Tween 80 was used in combination with buffer (pH 7.4) to increase the solubility of Nimesulide. The results show that the dependence of the released amount on the Tween concentration is not linear, very low Tween concentration showing a decrease of "solubility", probably connected to a critical micelle concentration at the interface Nimesulide solution. An "analytical" artefact connected to a decreasing ultraviolet absorption of Nimesulide because of Nimesulide precipitation, the formation of a colloidal solution is possible, and the phenomenon remains to be searched further. It is hard to explain that for an almost complete solubilization a significant Tween quantity is necessary and this should be more than that of other slightly soluble drugs.

Physico-chemical characterization and in vitro dissolution assessment of clonazepam-cyclodextrins inclusion compounds

The objectives of this research were to prepare and characterize inclusion complexes of clonazepam with beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin and to study the effect of complexation on the dissolution rate of clonazepam, a water-insoluble lipid-lowering drug. The phase-solubility profiles with both cyclodextrins were classified as AP-type, indicating the formation of 2:1 stoichiometric inclusion complexes. Gibbs free energy (DeltaG(tr)(degree)) values were all negative, indicating the spontaneous nature of clonazepam solubilization, and they decreased with increase in the cyclodextrins concentration, demonstrating that the reaction conditions became more favorable as the concentration of cyclodextrins increased. Complexes of clonazepam were prepared with cyclodextrins by various methods such as kneading, coevaporation, and physical mixing. The complexes were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry studies. These studies indicated that complex prepared kneading and coevaporation methods showed successful inclusion of the clonazepam molecule into the cyclodextrins cavity. The complexation resulted in a marked improvement in the solubility and wettability of clonazepam. Among all the samples, complex prepared with hydroxypropyl-beta-cyclodextrin by kneading method showed highest improvement in in vitro dissolution rate of clonazepam. Mean dissolution time of clonazepam decreased significantly after preparation of complexes and physical mixture of clonazepam with cyclodextrins. Similarity factor indicated significant difference between the release profiles of clonazepam from complexes and physical mixture and from plain clonazepam. Tablets containing complexes prepared with cyclodextrins showed significant improvement in the release profile of clonazepam as compared to tablet containing clonazepam without cyclodextrins.

Co-solvent solubilization of some poorly-soluble antidiabetic drugs

Co-solvent solubilization approach has been used to enhance the solubility of seven antidiabetic drugs: gliclazide, glyburide, glipizide, glimepiride, repaglinide, pioglitazone, and roziglitazone. Solubility in water, phosphate buffer (pH 7.4), six co-solvent solutions prepared in water as well as phosphate buffer (pH 7.4) and pH-solubility profile of various drugs have been determined at 25 degrees C. Aqueous solubility of various drugs was found to be less than 0.04 mg/mL. Solubility of gliclazide, glipizide and repaglinide increased by 3-6 times by using phosphate buffer (pH 7.4) as solvent. Solubility enhancement by pH modification was not sufficient. Significant enhancement in solubility could be achieved by the use of co-solvents. The combined effect of co-solvent and buffer was synergistic and enormous increase in solubility of sulfonylureas and repaglinide could be achieved. In the case of glitazones, however, co-solvent alone caused significant enhancement; the presence of buffer had negative effect on the solubilization potential of the co-solvents. Up to 763, 316, 153, 524, 297, 792 and 513 times increase in solubility could be achieved in the case of gliclazide, glyburide, glimepiride, glipizide, repaglinide, pioglitazone and rosiglitazone, respectively.

Electrospray photoionization (ESPI) liquid chromatography/mass spectrometry for the simultaneous analysis of cyclodextrin and pharmaceuticals and their binding interactions

We report on the use of a multimode electrospray ionization/atmospheric pressure photoionization source (ESI/APPI or ESPI for short) with liquid chromatography/mass spectrometry (LC/MS) to measure all components of a mixed-polarity liquid sample containing: (1) low-polarity component (hormone, pharmaceutical or sterol), (2) polar component (cyclodextrin substrate), and (3) bound polar complex. The ESPI source has several advantages over both single ESI and multimode electrospray ionization/chemical ionization (ESCI) analysis, including an enhanced bound-complex detection and better performance at lower solvent flow rates. Relative binding constants are determined with (i) ESI mode, resulting in relative R(ESI-MS) values, and (ii) both ESI and APPI modes, providing relative K(D) values. We find that low molecular-substitution (Ms) values of cyclodextrin, i.e., Ms = 0.4, preferentially bind to the low-polarity compounds tested. This investigation is intended to demonstrate the feasibility of ESPI as an additional tool for investigating mixed-polarity binding systems, providing mass-specific data for all solution components, both polar and non-polar.

Tablet formulation studies on nimesulide and meloxicam-cyclodextrin binary systems

The objective of this work was to develop tablet formulations of nimesulide-beta-cyclodextrin (NI-beta-CD) and meloxicam-gamma-cyclodextrin (ME-gamma-CD) binary systems. In the case of nimesulide, 3 types of binary systems--physical mixtures, kneaded systems, and coevaporated systems--were studied. In the case of meloxicam, 2 types of binary systems--physical mixtures and kneaded systems--were investigated. Both drug-CD binary systems were prepared at 1:1 and 1:2 molar ratio (1:1M and 1:2M) and used in formulation studies. The tablet formulations containing drug-CD binary systems prepared by the wet granulation and direct compression methods showed superior dissolution properties when compared with the formulations of the corresponding pure drug formulations. Overall, the dissolution properties of tablet formulations prepared by the direct compression method were superior to those of tablets prepared by the wet granulation method. Selected tablet formulations showed good stability with regard to drug content, disintegration time, hardness, and in vitro dissolution properties over 6 months at 40 degrees C +/- 2 degrees C and 75% relative humidity.

Sildenafil/cyclodextrin complexation: Stability constants, thermodynamics, and guest–host interactions probed by 1H NMR and molecular modeling studies

Guest-host interactions of sildenafil (Sild) with cyclodextrins (CyDs) have been investigated using several techniques including phase solubility diagrams (PSD), differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD), proton nuclear magnetic resonance (1H NMR) and molecular mechanical modeling (MM+). Estimates of the complex formation constant (K11) show that the tendency of Sild to complex with CyDs follows the order: beta-CyD>HP-beta-CyD>gamma-CyD, alpha-CyD, where K11 values at pH 8.7 and 30 degrees C were 150, 68 and 46, 43 M-1, respectively. Ionization of Sild reduces its tendency to complex with beta-CyD, where protonated (at pH 3.6) and anionic Sild (at pH 12.1) species have K11 values of 17 and 42 M-1, respectively, compared with 150 M-1 for neutral Sild (at pH 8.7). The hydrophobic character of Sild was found to provide 39% of the driving force for complex stability, while other factors including specific interactions contribute -7.9 kJ/mol. Complex formation of Sild with beta-CyD (DeltaG degrees=-22.9 kJ/mol) is largely driven by enthalpy (DeltaH degrees=-19.8 kJ/mol) and slight entropy (DeltaS degrees=10.3 J/molK) changes. 1H NMR and MM+ studies indicate formation of two isomeric 1:1 complexes: one involving complete inclusion of the phenyl-moiety into the beta-CyD cavity while the other pertaining to partial inclusion of the pyrimidinone moiety. The dominant driving force for complexation is evidently van der Waals with very little electrostatic contribution. DSC, XRPD and 1H NMR studies proved the formation of inclusion complex in solution and the solid state.

Tablet formulation containing meloxicam and beta-cyclodextrin: mechanical characterization and bioavailability evaluation

The purpose of this research was to evaluate beta-cyclodextrin (beta-CD) as a vehicle, either singly or in blends with lactose (spray-dried or monohydrate), for preparing a meloxicam tablet. Aqueous solubility of meloxicam in presence of beta-CD was investigated. The tablets were prepared by direct compression and wet granulation techniques. The powder blends and the granules were evaluated for angle of repose, bulk density, compressibility index, total porosity, and drug content. The tablets were subjected to thickness, diameter, weight variation test, drug content, hardness, friability, disintegration time, and in vitro dissolution studies. The effect of beta-CD on the bioavailability of meloxicam was also investigated in human volunteers using a balanced 2-way crossover study. Phase-solubility studies indicated an A(L)-type diagram with inclusion complex of 1:1 molar ratio. The powder blends and granules of all formulations showed satisfactory flow properties, compressibility, and drug content. All tablet formulations prepared by direct compression or wet granulation showed acceptable mechanical properties. The dissolution rate of meloxicam was significantly enhanced by inclusion of beta-CD in the formulations up to 30%. The mean pharmacokinetic parameters (C(max), K(e), and area under the curve [AUC](0-infinity)) were significantly increased in presence of beta-CD. These results suggest that beta-CD would facilitate the preparation of meloxicam tablets with acceptable mechanical properties using the direct compression technique as there is no important difference between tablets prepared by direct compression and those prepared by wet granulation. Also, beta-CD is particularly useful for improving the oral bioavailablity of meloxicam.

Formulation design and optimization of mouth dissolve tablets of nimesulide using vacuum drying technique

The purpose of this research was to develop mouth dissolve tablets of nimesulide. Granules containing nimesulide, camphor, crospovidone, and lactose were prepared by wet granulation technique. Camphor was sublimed from the dried granules by exposure to vacuum. The porous granules were then compressed. Alternatively, tablets were first prepared and later exposed to vacuum. The tablets were evaluated for percentage friability, wetting time, and disintegration time. In the investigation, a 32 full factorial design was used to investigate the joint influence of 2 formulation variables: amount of camphor and crospovidone. The results of multiple linear regression analysis revealed that for obtaining a rapidly disintegrating dosage form, tablets should be prepared using an optimum concentration of camphor and a higher percentage of crospovidone. A contour plot is also presented to graphically represent the effect of the independent variables on the disintegration time and percentage friability. A checkpoint batch was also prepared to prove the validity of the evolved mathematical model. Sublimation of camphor from tablets resulted in superior tablets as compared with the tablets prepared from granules that were exposed to vacuum. The systematic formulation approach helped in understanding the effect of formulation processing variables.