Influence of preparation methodology on solid-state properties of an acidic drug-cyclodextrin system

In vitro and in vivo effects of morin on the intestinal absorption and pharmacokinetics of olmesartan medoxomil solid dispersions

PURPOSE

In-situ evaluation to corroborate morin effects on the intestinal absorption and pharmacokinetic behavior of freeze-dried OLM-loaded solid dispersions with Caco-2 and in-vivo studies Methods: Intestinal transport and absorption studies were examined by Caco-2 permeability, in-situ single pass perfusion and closed-loop models along with in-vivo pharmacokinetic studies to evaluate and confirm the effect of P-gp-mediated activity of morin. We evaluated the intestinal membrane damage in the presence of morin by measuring the release of protein and lactate dehydrogenase (LDH) followed by using qualitative and quantitative morphometric analysis to describe the surface characteristics of intestinal epithelium.

RESULTS

Morin showed the highest P_eff value 13.8 ± 0.34 × 10^-6cm/s in jejunum than ileum (p < .01) at 100 µM with absorption enhancement of 1.31-fold together with enhanced (p < .01) secretory transport of 6.27 ± 0.27 × 10 ^-6cm/s in Caco-2 monolayer cells. Our findings noticed 2.37 (in-situ); 2.39 (in-vivo) and 1.43 (in-situ); 1.36 (in-vivo) fold increase in AUC_0-t with elevated C_max and shortened T_max for freeze-dried solid dispersion in the presence of morin as compared to pure OLM and freeze-dried solid dispersions without morin, respectively.

CONCLUSIONS

Our study demonstrated that increased solubilization through freeze-dried OLM-loaded solid dispersion together with efflux inhibition improved intestinal permeability to one system that might lead to novel solubilization and efflux pump inhibition as a novel alternative potential to increase oral absorption and bioavailability of OLM.

Preparation and characterization of mosapride citrate inclusion complexes with natural and synthetic cyclodextrins

The aim of this work was to investigate the inclusion complexes between mosapride citrate and SBE7β-CD in comparison with the natural β-CD to enhance its bioavailability by improving the solubility and dissolution rate. The complexation efficiency value of SBE7β-CD was higher than that for β-CD. Solid binary systems of mosapride citrate with CDs were prepared by physical mixing, kneading and freeze-drying techniques at molar ratio of 1:1(drug:CD). Physicochemical characterization of the prepared systems was studied using X-ray diffractometry, differential scanning calorimetry, Fourier-transform infrared spectroscopy and scanning electron microscopy (SEM). Amorphous drug was detectable to large extent in inclusion complexes prepared using the freeze-drying technique. From the dissolution study of different inclusion complexes in simulated saliva solution (pH 6.8), we could concluded that irrespective of the preparation technique, the systems prepared using SBE7β-CD showed better performance than the corresponding ones prepared using β-CD. In addition, the freeze-drying technique showed superior dissolution enhancement than other methods especially when combined with the SBE7β-CD.

Development of effervescent tablets containing benznidazole complexed with cyclodextrin

Objectives

Benznidazole (BNZ), the primary chemotherapy agent used to treat Chagas disease, has poor aqueous solubility, which results in low bioavailability. The purpose of this work was to develop stable effervescent tablets using an inclusion complex of BNZ with cyclodextrin (CD).

Method

In the first phase, different CDs were evaluated according to their ability to improve the aqueous solubility of BNZ. Then, inclusion complexes of BNZ in the solid state were produced by the kneading method and the complexes were evaluated using several physical–chemical assays. Finally, effervescent tablets were prepared according to a complete 32 factorial design. The effects of the concentration of CD and effervescent mixture on the dissolution rate and physical stability of tablets were evaluated.

Key findings

Hydroxypropyl-β-cyclodextrin produced the greatest improvement in the aqueous solubility of BNZ, almost 20-times greater than the water system. Solid systems produced with BNZ and CD showed physical–chemical interactions and increased the drug dissolution rate, suggesting the formation of a true solid inclusion complex. Moreover, the effervescent matrix of the tablets was effective in improving the dissolution behaviour of BNZ complexed with CD.

Conclusions

Effervescent tablets produced using an inclusion complex of BNZ with CD suggest a possible improvement in the bioavailability of BNZ, and this could represent a relevant advance in Chagas therapy.

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.

Extended release promethazine HCl using acrylic polymers by freeze-drying and spray-drying techniques: formulation considerations

The present study investigated a novel extended release system of promethazine hydrochloride (PHC) with acrylic polymers Eudragit RL100 and Eudragit S100 in different weight ratios (1:1 and 1: 5), and in combination (0.5+1.5), using freeze-drying and spray-drying techniques. Solid dispersions were characterized by Fourier-transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), Powder X-ray diffractometry (PXRD), Nuclear magnetic resonance (NMR), Scanning electron microscopy (SEM), as well as solubility and in vitro dissolution studies in 0.1 N HCl (pH 1.2), double-distilled water and phosphate buffer (pH 7.4). Adsorption tests from drug solution to solid polymers were also performed. A selected solid dispersion system was developed into capsule dosage form and evaluated for in vitro dissolution studies. The progressive disappearance of drug peaks in thermotropic profiles of spray-dried dispersions were related to increasing amount of polymers, while SEM studies suggested homogenous dispersion of drug in polymer. Eudragit RL100 had a greater adsorptive capacity than Eudragit S100, and thus its combination in (0.5+1.5) for S100 and RL 100 exhibited a higher dissolution rate with 97.14% drug release for twelve hours. Among different formulations, capsules prepared by combination of acrylic polymers using spray-drying (1:0.5 + 1.5) displayed extended release of drug for twelve hours with 96.87% release followed by zero order kinetics (r²= 0.9986).

Formulation Studies and In Vivo Evaluation of a Flurbiprofen-Hydroxypropyl β-Cyclodextrin System

The purpose of this study was 1) to investigate in vivo advantages of a flurbiprofen (FPN)-hydroxypropyl beta-cyclodextrin (HPbetaCD) solid dispersion (SD) in rats, 2) to study factors affecting the drug release from SD formulations, and 3) to evaluate the pharmacokinetic profile of the drug when administered as SD, in humans. The solubility of FPN in water and dissolution media was evaluated as a function of HPbetaCD concentration. The SD was prepared by coevaporation from dilute aqueous NH3 and evaluated in rats. The release of the drug from tablet formulations and capsules of SD was studied in simulated gastric fluid and phosphate buffer, pH 7.2. The bioavailability of drug when administered as SD was evaluated in humans. HPbetaCD enhanced the solubility of the drug, and SD improved bioavailability and reduced ulcerogenicity of the drug in rats. The type of excipient used affected drug release from tablets. Presence of microcrystalline cellulose, a hydrophilic polymeric excipient, resulted in uptake of water and stabilization of the resulting gels-like structure of HPbetaCD-containing tablets. This adversely affected drug release. The release from capsules filled with SD was comparable to that obtained from plain SD powder. The drug-HPbetaCD association constant in water was much lower than the values reported in literature. The bioavailability (which could suffer in case of higher association constant) was enhanced on administration of SD-filled capsules to humans.

Formulation and evaluation of fast dissolving films for delivery of triclosan to the oral cavity

The present investigation was undertaken with the objective of formulating TC containing fast dissolving films for local delivery to oral cavity. Various film forming agents, film modifiers and polyhydric alcohols were evaluated for optimizing the composition of fast dissolving films. The potential of poloxamer 407 and hydroxypropyl-beta- cyclodextrin (HPBCD) to improve solubility of TC was investigated. Fast dissolving films containing hydroxypropyl methylcellulose (HPMC), xanthan gum, and xylitol were formulated. Use of poloxamer 407 and HPBCD resulted in significant improvement in the solubility of TC. Fast dissolving films containing TC-HPBCD complex and TC-Poloxamer 407 were formulated and were evaluated for the in vitro dissolution profile and in vitro microbiological assay. Films containing TC-Poloxamer 407 exhibited better in vitro dissolution profile and in vitro antimicrobial activity as compared to the films containing TC-HPBCD complex. Effect of incorporation of eugenol on the in vivo performance of TC-Poloxamer 407 containing films was evaluated in human volunteers. Eugenol containing films improved the acceptability of TC-Poloxamer 407 films with respect to taste masking and mouth freshening without compromising the in vivo dissolution time.

Comparative Evaluation of Ibuprofen/β-Cyclodextrin Complexes Obtained by Supercritical Carbon Dioxide and Other Conventional Methods

PURPOSE

The preparation of drug/cyclodextrin complexes is a suitable method to improve the dissolution of poor soluble drugs. The efficacy of the Controlled Particle Deposition (CPD) as a new developed method to prepare these complexes in a single stage process using supercritical carbon dioxide is therefore compared with other conventional methods.

MATERIALS AND METHODS

Ibuprofen/beta-cyclodextrin complexes were prepared with different techniques and characterized using FTIR-ATR spectroscopy, powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). In addition, the influences of the processing technique on the drug content (HPLC) and the dissolution behavior were studied.

RESULTS

Employing the CPD-process resulted in a drug content of 2.8+/-0.22 wt.% in the carrier. The material obtained by CPD showed an improved dissolution rate of ibuprofen at pH 5 compared with the pure drug and its physical mixture with beta-cyclodextrin. In addition CPD material displays the highest dissolution (93.5+/- 2.89% after 75 min) compared to material obtained by co-precipitation (61.3 +/-0.52%) or freeze-drying (90.6 +/-2.54%).

CONCLUSION

This study presents the CPD-technique as a well suitable method to prepare a drug/beta-cyclodextrin complex with improved drug dissolution compared to the pure drug and materials obtained by other methods.