Design,Preparation and Evaluation of HPMC-Based PAA or SA Freeze-Dried Scaffolds for Vaginal Delivery of Fluconazole

Purpose

Aim of this work was preparation of bioadhesive gel formulations based on Hydroxypropyl methylcellulose (HPMC), Poly(acrylic acid) (PAA) or Sodium alginate (SA) loaded with anise/fluconazole β-cyclodextrin inclusion complexes in 1:2 and 1:3 ratios intended for vaginal applications.

Methods

Freeze-drying method was effectively utilized and superporous morphology was obtained. The superporous morphology of the lyophilized gels, dynamic water vapor sorption measurements, drug release kinetics studies and their antimicrobial activities are presented.

Results

HPMC content influences especially the sorption/desorption behaviour of HPMC-based PAA gels and the morphology of the gel formulations with fluconazole/β-cyclodextrin inclusion complexes, due to the interactions among the gel networks absorbing water molecules. It was found that fluconazole release kinetics correspond to quasi-Fickian, Fickian diffusion and non-Fickian mechanisms for the studied hydrogels. The tested vaginal formulations with β-cyclodextrin inclusion complexes exhibited selectivity toward S. aureus ATCC 25923 and all tested Candida strains in comparison with the gel formulation without β-cyclodextrin.

Conclusions

The fluconazole/β cyclodextrin inclusion complexes ensure a controlled release of fluconazole over a few days, the highest amount of drug release (92%) being observed after 43 h. These bioadhesive gel formulations could be very promising topical alternative for treatment of vaginal fungal infections.

     

Inclusion complexation of warfarin with cyclodextrins to improve some pharmaceutical characteristics

Inclusion complexation of warfarin and α- or β-cyclodextrins in water and in the solid phase were studied by a solubility method, a membrane permeation study, thin-layer chromatography, a dissolution study, IR spectroscopy and differential scanning calorimetry. The solubility of warfarin increased with the addition of cyclodextrins. The apparent stability constants of the α- and β-cyclodextrin complexes are 10.29M ^?1 and 148.88M ^?1 respectively. The greater the stability constant of the inclusion complex the lesser the permeability of warfarin. Solid complexes of warfarin and α- or β-cyclodextrins were obtained by freeze-drying. Clear differences in IR absorption spectra and DSC thermograms were observed between the inclusion complexes and physical mixtures. The dissolution rate of the freeze-dried warfarin-cyclodextrin complexes was increased about 1200-fold and 550-fold for α- and β-cyclodextrins, respectively. The dissolution rate of warfarin was significantly improved by complex formation.     

Improvement of thermal and photochemical stability of benzaldehyde by cyclodextrin complexation

Inclusion complexes of benzaldehyde (BA) with α-, β- and γ-cyclodextrins (α-, β-and γ-CyD) in water and in the solid phase were investigated by the solubility method, infrared spectroscopy, X-ray diffractometry and thermal analysis. The solid complexes of BA with all 3 CyDs were prepared, and their molar ratios were found to be 1:1 (BA/α-CyD), 3:2 (BA/β-CyD) and 2:1 (BA/γ-CyD). The volatility and photo-oxidation of BA were significantly retarded by the CyD inclusion complexation. The oxidation of BA was completely inhibited by 3 CyD complexes. The improved thermal and photochemical stabilities of BA by inclusion complexation suggest ease of handling with prolonged storage time.     

不同种类环糊精对穿心莲内酯的增溶效应研究

目的用相溶解度法考察β-环糊精（β-CD）、羟丙基-β-环糊精（HP-β-CD）和磺丁基醚-β-环糊精（SBE-β-CD）对穿心莲内酯（AND）的增溶作用。方法通过测定AND在不同浓度β-CD,HP-β-CD,SBE-β-CD溶液中的溶解度,绘制出AND的相溶解度曲线,计算各稳定常数。结果β-CD,HP-β-CD,SBE-β-CD均与AND形成摩尔比为1∶1的包合物,包合类型分别为BS型、AL型和AL型。在50 mmol/L的HP-β-CD溶液中,AND的溶解度比在水中的溶解度增加了60倍;在50mmol/L SBE-β-CD溶液中,AND的溶解度比在水中的溶解度增加了55.5倍。结论在3种环糊精中,增溶效果由强到弱依次为HP-β-CD,SBE-β-CD,β-CD。     

Meloxicam β-cyclodextrin transdermal gel: physicochemical characterization and in vitro dissolution and diffusion studies

The aim of the study was to develop a Meloxicam (ME) transdermal gel formulations based on complexation with β-cyclodextrin. ME β-Cyclodextrin gel formulations were prepared using four different gel bases with different concentrations and different permeation enhancers. The developed formulations were examined for their in vitro characteristics and their diffusion through a mouse skin. The gel formulations were prepared successfully. Physicochemical characterization of ME β-CD complex in solution state by phase solubility revealed 1:1 M complexation of ME with β-Cyclodextrin. ME release profiles from the inclusion complex were superior over ME alone. Hydroxypropyl methyl cellulose 15% w/w gel base was proven to be a suitable base for ME inclusion complex formulation as it provides a high drug release than other studied bases. ME β-CD complex gel formulations containing oleic acid (1% w/w) or (5% w/w) cineol used as permeation enhancers in (15% w/w) HPMC gel base were proven to provide a higher diffusion rate of the drug through the mouse skin. This is very promising in providing analgesic activity of meloxicam via topical route of administration.     

Physicochemical Characterization, in vitro Release and Permeation Studies of Respirable Rifampicin-Cyclodextrin Inclusion Complexes

The inclusion complexes of rifampicin with sucralose and β-cyclodextrins were prepared by spray drying method. The complexes were characterized by size analyses, scanning electron microscopy, differential scanning calorimetry and x-ray diffraction methods. The results indicated the amorphous nature of resultant products. The solubility, in vitro release and skin permeation of the drug were enhanced after formation of inclusion complexes. The in vitro release and permeation of the inclusion complexes were greater in simulated lung fluid as compared to pure drug.     

Improvement of photostability and dissolution profile of isradipine using inclusion complex

Inclusion complexes using β-cyclodextrin were manufactured by solvent evaporation method. Then, sustained release (SR) hydroxypropylmethylcellulose (HPMC) matrix tablets containing inclusion complex were prepared via direct compression. Isradipine was chosen as a model drug due to its low solubility, photo-instability and short elimination half-life. The physicochemical properties of the inclusion complexes were examined using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The solubility test and dissolution behaviours were also investigated. Based on the solubility experiments, a 1:2 molar ratio (isradipine:β-Cyclodextrin) was best and chosen to prepare inclusion complexes. In addition, the crystal structure of isradipine was converted to an amorphous structure, as confirmed by Fourier transform infrared spectroscopy (FT-IR) and DSC. The photostability of isradipine in the inclusion complex was more stable than pure isradipine after 4 days radiation. By using hypromellose as the hydrophilic sustained release material, the dissolution rate was retarded during 24 h. A combined method of inclusion complex and SR technology showed increased and sustained release profile above that of Dynacirc^® SR Cap. 5 mg.     

Inclusion complexes of tadalafil with natural and chemically modified β-cyclodextrins. I: Preparation and in-vitro evaluation

The aim of this work was to investigate the inclusion complexation between tadalafil, a practically insoluble selective phosphodiesterase-5 inhibitor (PDE5), and two chemically modified β-cyclodextrins: hydroxypropyl-β-cyclodextrin (HP-β-CD) and heptakis-[2,6-di-O-methyl]-β-cyclodextrin (DM-β-CD), in comparison with the natural β-cyclodextrin (β-CD) in order to improve the solubility and the dissolution rate of the drug in an attempt to enhance its bioavailability. Inclusion complexation was investigated in both the solution and the solid state. The UV spectral shift method indicated guest–host complex formation between tadalafil and the three cyclodextrins (CDs). The phase solubility profiles with all the used CDs were classified as A_p-type, indicating the formation of higher order complexes. The complexation efficiency values (CE), which reflect the solubilizing power of the CDs towards the drug, could be arranged in the following order: DM-β-CD > HP-β-CD > β-CD. Solid binary systems of tadalafil with CDs were prepared by kneading and freeze-drying techniques at molar ratios of 1:1, 1:3 and 1:5 (drug to CD). Physical mixtures were prepared in the same molar ratios for comparison. Physicochemical characterization of the prepared systems at molar ratio of 1:5 was studied using differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and Fourier-transform infrared spectroscopy (FTIR). The results showed the formation of true inclusion complexes between the drug and both HP-β-CD and DM-β-CD using the freeze-drying method at molar ratio of 1:5. In contrast, crystalline drug was detectable in all other products. The dissolution of tadalafil from all the prepared binary systems was carried out to determine the most appropriate CD type, molar ratio, and preparation technique to prepare inclusion complexes to be used in the development of tablet formulation for oral delivery of tadalafil. The dissolution enhancement was increased on increasing the CD proportion in all the prepared systems. Both the CD type and the preparation technique played an important role in the performance of the system. Irrespective of the preparation technique, the systems prepared using HP-β-CD and DM-β-CD yielded 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 β-CD derivatives.     

白杨素-羟丙基-β-环糊精包合物的制备与表征

目的为提高白杨素的水溶性和生物利用度,用羟丙基-β-环糊精对其进行包合,拓宽白杨素的药用途径。方法利用研磨法制备白杨素-羟丙基-β-环糊精包合物,通过粉末X射线衍射分析、差示扫描量热分析和红外光谱分析等方法对制备的白杨素-羟丙基-β-环糊精包合物进行鉴定和表征;应用紫外分光光度法对包合物的溶解度进行测定。结果白杨素与羟丙基-β-环糊精形成包合物,包合前后溶解度考察表明,形成包合物后白杨素的溶解度增加了120.7倍。结论羟丙基-β-环糊精对白杨素具有良好的增溶作用,白杨素环糊精包合物的制备方法简捷实用,达到了增加药物溶解度的目的,有助于白杨素的进一步开发利用。     

Improvement in solubility and stability of thalidomide by synthesis of inclusion complexes with cyclodextrins

Improvement of solubility and stability of thalidomide by inclusion complexation with cyclodextrins Thalidomide ( 1 ), which is only poorly soluble in water and also unstable due to spontaneous hydrolysis in aqueous solution, forms relatively stable inclusion complexes with β- and γ-cyclodextrin. The solubility in water can be increased thereby up to the fivefold. The half-life time of hydrolysis at pH 8.5 rises from less than 1 min for non-complexed 1 up to 170 and 30 min, respectively, for the β- and γ-cyclodextrin inclusion complex. α-Cyclodextrin, on the other hand, does not significantly improve the solubility of 1 , and it has no influence on its stability.     

Nasal delivery of insulin using bioadhesive chitosan gels

Recently nasal delivery of insulin has gained considerable attention. Some limitations of this route include rapid mucociliary clearance of the drug from the site of deposition resulting in short time span available for absorption and low permeability of the nasal membrane for peptides. The objective of the present study was development of a chitosan bioadhesive gel for nasal delivery of insulin. A nasal perfusion test was used to study the toxicity of 4 absorption enhancers: saponin, sodium deoxycholate, ethylendiamine tetra-Acetic Acid (EDTA) and lecithin. The gels contained 4000 Iu/dl insulin, 2 or 4% of low and medium molecular weight of chitosan, and lecithin or EDTA. Drug release was studied by a membraneless diffusion method and bioadhesion by a modified tensiometry test. The optimized gel was administered nasally in diabetic rats. The serum insulin levels were analyzed by an insulin enzyme immunoassay kit and serum glucose by glucose oxidase method kits. Formulations containing 2% of low molecular weight of chitosan with EDTA had higher release percentage and dissolution efficiency (DE)_2.5%, lower T_50% (Time required to release 50% of the drug), mean dissolution time, and bioadhesion than gels containing 4% of medium molecular weight of chitosan with lecithin. Insulin was released by a zero-order kinetic from the gels. The gel of 2% medium molecular weight of chitosan with EDTA caused increase in insulin absorption and reduction the glucose level by as much as 46% of the intravenous route. Considering our in vitro and in vivo studies, the proposed gel formulation could be a useful preparation for controlled delivery of insulin through the nasal route.     

氟非尼酮凝胶的研制及其体外透皮转运

采用HPLC法测定了25℃、100 r/min条件下平衡48 h时氟非尼酮在水性溶剂和非水溶剂中的溶解度。结果表明,氟非尼酮在水及其他水性溶剂中微溶,溶解度约为2.5 mg/ml,溶剂的pH值对溶解度影响小;氟非尼酮易溶于乙醇,可溶于聚乙二醇400、1,2-丙二醇和异丙醇,微溶于甘油。摇瓶法测得氟非尼酮的油水分配系数(logP)值为1.182,略有亲脂性。以乳猪皮肤为模型,采用改良的Franz扩散池法评价不同载药量(0.5%和1%)凝胶及溶液的经皮渗透特性。结果表明,2种载药量的氟非尼酮凝胶的经皮渗透行为均符合零级模型,1%凝胶的24 h单位面积累积渗透量(Q24h)和单位面积皮肤滞留量(Qskin)均比0.5%凝胶增加约1倍;同时,0.5%溶液的Q24h和Qskin结果介于2种载药量凝胶之间。     

Complexation of the sunscreen agent,butyl-methoxydibenzoylmethane,with hydroxypropyl-β-cyclodextrin.

The interaction between the sunscreen, butyl-methoxydibenzoylmethane (BM-DBM), and parent and modified α-, β- or γ-cyclodextrins was investigated in water by phase-solubility analysis. Among the available cyclodextrins, only hydroxypropyl-β-cyclodextrin (HP-β-CD) produced a significant increase in the aqueous solubility of BM-DBM. The complexation of the sunscreen agent with HP-β-CD was studied by circular dichroism, differential scanning calorimetry and X-ray diffractometry. The data from the solubility and the circular dichroism studies suggested the formation of a 1:2 (sunscreen:cyclodextrin) complex. The photodegradation of BM-DBM was reduced by inclusion complexation with HP-β-CD. Therefore the complex can be used to improve the photostability of the sunscreen agent.     

Native and β-cyclodextrin-enclosed curcumin: entrapment within liposomes and their in vitro cytotoxicity in lung and colon cancer

With a view to improving the solubility and delivery characteristics of poorly water-soluble drugs, we prepared β-cyclodextrin-curcumin (βCD-C) inclusion complexes (hydrophilic curcumin) and entrapped both native curcumin (hydrophobic) and the complexes separately into liposomes; these were then assessed for in vitro cytotoxicity in lung and colon cancer cell lines. Optimization of curcumin entrapment within βCD was achieved, with the resultant βCD-C complexes prepared by methanol reflux. Inclusion complexes were confirmed using UV spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction. The water solubility of βCD-C complexes improved markedly (c.f. native curcumin) and successful entrapment of complexes into liposomes, prepared using a thin-film hydration approach, was also achieved. All the liposomal formulations were characterized for curcumin and βCD-C complex entrapment efficiency, particle size, polydispersity and stability at 2–8°C. Curcumin, βCD-C complex and their optimized liposomal formulations were evaluated for anticancer activity in lung (A-459) and colon (SW-620) cancer cell lines. All curcumin-containing formulations tested were effective in inhibiting cell proliferation, as determined via an MTT assay. The median effective dose (EC₅₀) for all curcumin formulations was found to be in the low µM range for both lung and colon cancer cell lines tested. Our results confirm that βCD inclusion complexes of poorly water soluble drugs, such as curcumin can be entrapped within biocompatible vesicles such as liposomes, and this does not preclude their anticancer activity.     

Randomly methylated β-cyclodextrin derivatives enhance taxol permeability through human intestinal epithelial Caco-2 cell monolayer

Intestinal absorption and bioavailability of taxol are limited by its low solubility and P-glycoprotein (Pgp) activity. Methylated β-cyclodextrins (CDs) effectively form complexes with paclitaxel but randomly methylated β-cyclodextrin (RAMEB) is cytotoxic in high concentrations. Second-generation derivatives containing monoamino (MaRAMEB) and succinylated (SuRAMEB) ionic substituents with similar inclusion capacity but less toxicity could be promising alternatives of RAMEB. Our aim was to examine and compare the efficacy of MaRAMEB and SuRAMEB with the parental RAMEB on taxol bidirectional permeability using the Caco-2 model. Taxol permeability was not changed by 30-min pretreatment with CDs. In co-treatment with β-cyclodextrins, the apical to basolateral taxol flux was 4 to 6 times greater than in untreated monolayers and it was also higher than in cells treated with Pgp inhibitor cyclosporin A. No decrease in basolateral to apical taxol flux was observed in pretreatment or co-treatment with CDs, suggesting no Pgp inhibition. All three CDs showed similar effects on taxol permeability but RAMEB altered tight junction protein distribution and significantly decreased transepithelial electrical resistance. None of the CDs modified paracellular permeability to mannitol and polyethylene glycol 4000. In conclusion, second-generation derivatives of methyl-β-cyclodextrin, especially MaRAMEB, enhanced taxol permeability across Caco-2 cells with less toxicity and similar effectiveness as RAMEB.     

水合氯醛β-环糊精包合物干糖浆剂的制备与质量控制

目的:制备水合氯醛β-环糊精包合物干糖浆剂并建立测定该制剂中水合氯醛含量的气相色谱法。方法:采用饱和水溶液法制备水合氯醛β-环糊精包合物,湿法制粒法制备干糖浆剂;采用气相色谱内标(正己烷)法测定制剂中水合氯醛含量,色谱柱为Rtx-1毛细管柱,氢离子火焰检测器温度为250℃,进样口温度为200℃。结果:所制制剂为白色颗粒,其鉴别和检查等符合相关规定;水合氯醛检测浓度线性范围为2.5～25mg.mL-1(r=0.9990),回收率为99.24%,RSD=1.14%(n=6)。结论:制剂制备方法简单、可行。建立的含量测定方法简便、灵敏、专属性强、重复性好,可用于该制剂的质量控制。     

Cyclodextrin-water soluble polymer ternary complexes enhance the solubility and dissolution behaviour of poorly soluble drugs. Case example: Itraconazole

The aim of the present series of experiments was to improve the solubility and dissolution/precipitation behaviour of a poorly soluble, weakly basic drug, using itraconazole as a case example. Binary inclusion complexes of itraconazole with two commonly used cyclodextrin derivatives and a recently introduced cyclodextrin derivative were prepared. Their solubility and dissolution behaviour was compared with that of the pure drug and the marketed formulation Sporanox®. Ternary complexes were prepared by addition of Soluplus®, a new highly water soluble polymer, during the formation of the itraconazole/cyclodextrin complex. A solid dispersion made of itraconazole and Soluplus® was also studied as a control. Solid state analysis was performed for all formulations and for pure itraconazole using powder X-ray diffraction (pX-RD) and differential scanning calorimetry (DSC). Solubility tests indicated that with all formulation approaches, the aqueous solubility of itraconazole formed with hydroxypropyl-β-cyclodextrin (HP-β-CD) or hydroxybutenyl-β-cyclodextrin (HBen-β-CD) and Soluplus® proved to be the most favourable formulation approaches. Whereas the marketed formulation and the pure drug showed very poor dissolution, both of these ternary inclusion complexes resulted in fast and extensive release of itraconazole in all test media. Using the results of the dissolution experiments, a newly developed physiologically based pharmacokinetic (PBPK) in silico model was applied to compare the in vivo behaviour of Sporanox® with the predicted performance of the most promising ternary complexes from the in vitro studies. The PBPK modelling predicted that the bioavailability of itraconazole is likely to be increased after oral administration of ternary complex formulations, especially when itraconazole is formulated as a ternary complex comprising HP-β-CD or HBen-β-CD and Soluplus®.     

Enhancement of solubility and dissolution rate of poorly water-soluble naproxen by complexation with 2-hydroxypropyl-β-cyclodextrin

The solubility and dissolution rate of naproxen (NPX) complexed with 2-hydroxypropyl-β-cyclodextrin (2-HPβCD) using coprecipitation, evaporation, freeze-drying and kneading method were investigated. Solubility of NPX linearly increased (correlation coefficient, 0.995) as 2-HP-βCD concentration increased, resulting in A_L type phase solubility curve. Inclusion complexes prepared by four different methods were compared by differential scanning calorimetry (DSC). The NPX showed sharp endothermic peak around 156°C but inclusion complexes by evaporation, freeze-drying and kneading method showed very broad peak without distinct phase transition temperature. In contrast, inclusion complex prepared by coprecipitation method resulted in detectable peak around 156°C which is similar to NPX, suggesting incomplete formation of inclusion complex. Dissolution rate of inclusion complexes prepared by evaporation, freeze-drying and kneading except coprecipitation method was largely enhanced in the simulated gastric and intestinal fluid when compared to NPX powder and commercial NAXEN^® tablet. However, about 65% of NPX in gastric fluid still remained unreleased but most of NPX dissolved within 5 min in intestinal fluid. In case of inclusion complex prepared by coprecipitation method, formation of inclusion complex appeared to be incomplete, resulting in no marked enhancement of dissolution rate. From these findings, inclusion complexes of poorly water-soluble NPX with 2-HPβCD were useful to increase solubility and dissolution rate, resulting in enhancement of bioavailability and minimization of gastrointestinal toxicity of drug upon oral administration of inclusion complex.     

氯化血红素在β—环糊精包合前后溶解度和溶出度的研究

探讨氯化血红素用β－环糊精包合后的溶解度和体外溶出度,溶解度采用离心法,将氯化血红素及包合物用水配成饱和溶液,取适量以４００ｒ．ｍｉｎ＾－１离心,然后按分光光度法测定含量,溶出度采用桨法（中国药典二部二法）,以人工肠液为溶出介质,用分光光度法测定氯化血红素的含量。结果显示氯化血红素用β－环糊精包合后,溶解度和体外溶出度均有显著提高,制得的包合物水溶性好,体外溶出快,制备工艺简单易行。进一步证实包合物制备方法的可行性,同时也为氯化血红素加工成各种剂型开辟良好的前景。     

Gravity-induced coating flows of vaginal gel formulations: in vitro experimental analysis

Efficacy of topical microbicidal drug delivery formulations against HIV depends in part on their coating distributions and retention on vaginal epithelium. This study focused on gravity-induced coating flows of vaginal gels, and effects of formulation composition and surface wettability on coating. We hypothesized that presence of a yield stress, and surface wettability, affect coating. Experiments imaged and analyzed coating flows of gels on inclined model hydrophilic or hydrophobic surfaces. The in vitro wettability conditions bracket those believed to exist on vaginal epithelium in vivo. Six commercial vaginal gels were studied: three polyacrylic acid-based (PAA) and three cellulose-based. Our research group uses these gels in complementary human in vivo studies and other in vitro experimental analyses; this study is a first step in linking the in vivo and in vitro measurements. Coating by PAA gels was different from cellulose-based gels: the former exhibited yield stresses, which prevented initial gel shape from deforming during sliding. Coating flows of cellulose gels depended upon surface wettability. The slipping rates of the PAA gels ranked inversely with fitted yield stress values. The coating flow rates of the cellulose gels (hydrophilic surface) did not correlate with consistency index, but ranked inversely with the shear-thinning index. This study introduces a simple methodology for comparing trial formulations and relating their flows to gel constituents and physical properties. It also suggests differences in coating by current commercial gels.