Sustained release bioadhesive effervescent ketoconazole microcapsules tabletted for vaginal delivery

Microcapsules of ketoconazole with 1:1 and 1:2 core-wall ratios were prepared by means of the phase separation technique using sodium carboxymethylcellulose as a coating material. The microcapsules were mixed with effervescent granules and were tabletted. Dissolution studies of microcapsules, tabletted microcapsules and commercial ovules were carried out with a new basket method (horizontal rotating basket). A good sustained action was obtained with tablets. Micromeritic investigations were carried out on microcapsules in order to standardize the microcapsule product and to optimize the pilot production of the dosage forms prepared with these microcapsules. Bulk volume and weight, tapping volume and weight, fluidity, angle of repose, weight deviation, relative deviation, particle size distribution, density and porosity values of the microcapsules were determined. In addition, to evaluate whether some kind of glidant will be needed during tabletting of microcapsules, the Hausner ratio and consolidation index were also calculated and it may be concluded that microcapsules do not need any glidant.     

复方酮替长效阴道黏附片的制备及体外评价

目的制备复方酮替黏附性阴道片,并进行体外评价。方法对HPMC 60SH-4000,90SH-4000,60SH-10000,90SH-10000黏附材料进行溶胀率和黏附性的考察基础上,选用HPMC 60SH-4000为黏附剂,加入泡腾剂,PEG-6000,F68设计8种复方酮替黏附片处方,比较不同处方的溶胀率、黏附力、体外释放度等指标。结果处方最佳组成为HPMC 60SH-4000300mg,PEG-6000 50mg,泡腾剂50mg(摩尔比NaHCO3:Citric acid=3:1),替硝唑和酮康唑24h累积释放度为90.07%和86.54%。结论复方酮替黏附性阴道片制备方便,具有缓释的效果,有望成为治疗妇科感染的新剂型。     

An in vitro investigation for vaginal bioadhesive formulations: bioadhesive properties and swelling states of polymer mixtures

Bioadhesive tablet formulations have been developed for mucosal application. Sixteen different bioadhesive tablet formulations were prepared and evaluated. Their bioadhesion to vaginal mucosa were studied by tensile testing method. The swelling behaviour of the tablets in three different solutions was also investigated. In addition, the effect of the formulations on pH of the medium was followed. The most favorable formulation resulted a mixture of Carbopol 934 and Pectin (2:1). The highest bioadhesive strength, the highest swelling volume and the lowest pH reduction were obtained with this formulation.     

中华猕猴桃多糖的提取及泡腾片的工艺研究

目的确定中华猕猴桃多糖的最佳提取工艺;改进泡腾片的制备工艺,提高制剂稳定性。方法以苯酚-硫酸比色法测定多糖含量,λmax=490nm,采用正交设计方法优选提取工艺和制剂工艺。结果最佳提取工艺为用20倍水提,每次0.5h,提2次。最佳制剂工艺为碳酸氢钠11.25%,柠檬酸7.5%,采用5%聚乙二醇包裹碳酸氢钠,并以此工艺制成泡腾片。结论改进工艺优于常用工艺,切实可行。     

RP-HPLC法测定格尔德霉素阴道泡腾片的含量和有关物质

目的建立高效液相色谱法测定格尔德霉素阴道泡腾片的含量和有关物质。方法C18色谱柱(4.6mm×250mm,5μm),流动相为甲醇∶水(75∶25),流速1.0ml/min,检测波长304nm。结果线性范围0.72~72μg/ml,r=0.9999,高、中、低3种浓度平均回收率为:(102.9±1.15)%,(101.8±1.33)%,(102.4±2.49)%,日内精密度为0.35%~0.73%,日间精密度为0.63%~1.76%。结论该方法简便、快捷、准确。     

Technological and biological evaluation of tablets containing different strains of lactobacilli for vaginal administration

Ten strains of lactobacilli were evaluated for the administration of viable microorganisms to restore the normal indigenous flora in the treatment of urogenital tract infections (UTI) in women. As the strains considered are facultative anaerobes, optimization of the production process was particularly critical to preserve bacterial viability. The microorganisms were formulated in single- and double-layer vaginal tablets. The two layers were characterized by different release properties: one is an effervescent composition that ensures a rapid and complete distribution of the active ingredient over the whole vaginal surface; while the second is a sustained release composition capable of releasing the lactobacilli over a longer period of time. Three different retarding polymers were tested, and all the formulations and tablets were evaluated in terms of technological processability, bacterial viability and stability, and cell adhesion properties of the microorganisms. From the results obtained, three out of ten strains appear particularly suitable for their application in the treatment of UTI. A larger batch of tablets made with a mixture of the three strains was then evaluated, confirming the feasibility of their industrial production and a good bacterial viability in the final dosage form.     

Development and evaluation of a novel dry-coated tablet technology for pellets as a substitute for the conventional encapsulation technology

Pellet formulations as represented by multiparticulate systems are often contained in hard capsules. We examined the use of a different approach to the making of compressed tablets containing pellets, OSDRC-technology. OSDRC-technology employs a double-structure punch (center punch and outer punch) allowing for dry-coated tablets to be assembled in a single run. We examined the effects of the thickness of the outer punch, formability of pellets, and diameter of tablets on pellet filling. The results revealed that thinner outer punches are not always better for filling small tablets with large amounts of pellets. We considered that this was because the core pellets spread in a cone shape within the formulating tablets at filling, requiring a thickness of the outer punch and a particle density of the diluents at which pellets would not exude from the formulating tablets. It was suggested that the formability of core pellets affects the maximum number of layers of pellets, and higher formability would yield better results. However, we found that pellets with poor formability (tensile strength of < or =2 kPa) could be used in tablets. For the tablets, the larger the diameter, the greater the maximum number of layers. We considered this to be due to the friction between the pellets and punch wall. We concluded that OSDRC-technology could be applied to capsule-like forms containing pellets > or =50 wt% through an unconventional approach.     

齐多夫定缓释片的制备及体外评价

目的利用亲水性的Eudragit系列高分子物质单用、与疏水性的乙基纤维素合用制备齐多夫定骨架型缓释片。方法确定5个不同的处方，采用湿法制粒法制备骨架片。结果单独使用Eudragit系列产品作辅料，缓释片只能维持6h的药物持续释放，而RLPO、RSPO与乙基纤维素合用后可以维持12h的持续释药。结论齐多夫定缓释片与常规片比较，缓释片可以雏持12h的药物持续释放，这样会产生更好的治疗效果，减轻药物的副作用，大大改善患者依存率。     

A novel gastric-resident osmotic pump tablet: In vitro and in vivo evaluation

A novel famotidine gastric-resident osmotic pump tablet was developed. Pharmaceutical iron powder was used as a gas-formation and density-increasing agent. Central composite design-response surface methodology was used to investigate the influence of factors, i.e., polyethylene oxide (Mw 1,000,000) content, NaCl content, iron powder content and weight gain, on the responses including ultimate cumulative release and correlation coefficient of drug release profile. A second-order polynomial equation was fitted to the data and actual response values are in good accordance with the predicted ones. The optimized formulation displays a complete drug delivery and zero-order release rate. Gamma scintigraphy was selected as the method to monitor in vivo gastric residence time of the ^99mTc-labeled system in Beagle dogs. It was observed that the system can retain in stomach for an extended period of 7 h after administration compared with conventional tablets. The present investigation suggests that water-insoluble drug can be delivered from single-layer osmotic pump tablets completely due to the push power of the hydrogen gas generated by the reaction of the iron and gastric fluid. And iron powder can increase the system density which is over 2.5 g cm^?3, making the system resident in stomach to prolong the drug delivery time in absorption zone.     

In vitro and in vivo evaluation of WGA-carbopol modified liposomes as carriers for oral peptide delivery

Surface modification of liposomal nanocarriers with a novel polymer-lectin conjugate was proposed for enhancing the systemic uptake of encapsulated peptide and protein therapeutics after oral administration. Wheat germ agglutinin (WGA) was covalently attached to carbopol (CP) using the carbodiimide method. The prepared WGA-CP conjugate retained the biological cell binding activity of WGA without any evidence of cytotoxicity to Caco-2 monolayers. Cationic liposomes in the size range of 100 nm were prepared by the lipid film hydration method followed by probe sonication and surface modification with negatively charged WGA-CP. The uptake of WGA-CP liposomes by Caco-2 cells was significantly higher than that of non-modified or CP liposomes. The uptake was dependent on the surface concentration of WGA, temperature, and incubation period and was significantly inhibited in the presence of chlorpromazine and 10-fold excess of free WGA. These results suggest the involvement of active transport mechanism for the cellular uptake of the modified liposomes, mediated mainly by binding of WGA to its specific cell membrane receptors. Dual channel confocal microscopy confirmed the simultaneous association and internalization of the polymer conjugate and the liposomal carrier by Caco-2 cells and intestinal membrane of rats. In addition, the pharmacological efficacy of calcitonin, a model peptide drug, was enhanced by more than 20- and 3-fold following peroral administration of calcitonin-loaded WGA-CP liposomes when compared to non-modified and CP liposomes, respectively.     

Development of gastroretentive drug delivery system for cefuroxime axetil: In vitro and in vivo evaluation in human volunteers

The objective of this investigation was to develop the cefuroxime axetil sustained-release floating tablets to prolong the gastric residence time and compare their pharmacokinetic behavior with marketed conventional tablets (Zocef). The floating tablets were developed using polymers like HPMC K4M and HPMC K100M alone, and polymer combination of HPMC K4M and Polyox WSR 303 by effervescent technique. Tablets were prepared by slugging method and evaluated for their physical characteristics, in vitro drug release, and buoyancy lag time. The best formulation (F10) was selected based on in vitro characteristics and used in vivo radiographic and bioavailability studies in healthy human volunteers. All the formulations could sustain drug release for 12 h. The dissolution profiles were subjected to various kinetic release models and it was found that the mechanism of drug release followed Peppas model. The in vivo radiographic studies revealed that the tablets remained in stomach for 225±30 min. Based on in vivo performance, the developed floating tablets showed superior bioavailability than Zocef tablet. Based on in vivo performance significant difference was observed between C_max, t_max, t_1/2, AUC_0–∞, and mean residence time of test and reference (p<0.05). The increase in relative bioavailability of test was 1.61 fold when compared to reference.     

In vitro and in vivo characteristics of a thermogelling and bioadhesive delivery system intended for rectal administration of quinine in children

The aim of this work was to improve the rectal bioavailability of quinine hydrochloride by designing thermosensitive and mucoadhesive gels intended for rectal delivery. The rheological and mucoadhesive properties of poloxamer 407 solutions have been modulated by addition of hydroxypropylmethycellulose (HPMC) and propanediol-1,2. In vitro release and rectal absorption of quinine have been highlighted by a dialysis dissolution testing method and by the determination of bioavailability of the different formulations in rabbits. Increasing the proportions of HPMC and poloxamer in the formulations resulted in a prolonged release of quinine. Indeed, compared to the DT 50% of a rectal solution and a simple HPMC gel (27 and 65 min, respectively) the DT 50% of thermosensitive ternary systems was increased and ranged between 80 and 138 min, depending on the system composition. The release rate depended strongly on the elasticity of the gels after thermogelation. The absolute rectal bioavailability of quinine determined in rabbits was significantly improved with these thermosensitive and adhesive systems. It increased from 62% for the rectal solution to 98% for a ternary system 16/0.5/30 (poloxamer (16%)/HPMC (0.5%)/propanediol-1,2 (30%)). As a result of combined bioadhesion and prolonged release of quinine in vivo, higher average values of MRT and t_max (9.1 ± 0.2 h and 30 min, respectively) were obtained compared to the rectal solution (6.9 ± 0.9 h and 15 min, respectively). Moreover, these formulations presented a very good rectal tolerance.

Modulation by HPMC of the viscoelastic and mucoadhesive properties of poloxamer 407 thermogelling solutions allowed a prolonged release of quinine hydrochloride and an improvement of bioavailability in rabbit.     

Development and in vitro evaluation of a mucoadhesive vaginal delivery system for nystatin

The purpose of the present study was to design and evaluate a novel vaginal delivery system for nystatin based on mucoadhesive polymers. L-Cysteine and cysteamine, respectively, were covalently attached to poly(acrylic acid), and the two different thiolated polymers were evaluated in vitro regarding their swelling behavior, mucoadhesive properties and release behavior. Tablets comprising these thiolated polymers and nystatin demonstrated a high stability in vaginal fluid simulant pH 4.2 and an increase in weight by swelling whereas control tablets comprising unmodified poly(acrylic acid) disintegrated and dissolved. The mucoadhesion time of tablets on freshly excised bovine vaginal mucosa on a rotating cylinder and the total work of adhesion of gels and tablets increased significantly due to the formation of disulfide bonds between the thiolated polymer and cysteine rich subdomaines of the mucus layer. The drug nystatin was released more slowly out of thiomer tablets and gels than out of PAA control tablets and gels. Therefore these thiolated polymers are promising delivery systems for nystatin providing a prolonged residence time and a sustained drug release in vitro under physiological relevant conditions.     

Solid dispersion and effervescent techniques used to prepare docetaxel liposomes for lung-targeted delivery system: in vitro and in vivo evaluation

A lung-targeting liposomal docetaxel was developed to improve therapeutic index and to reduce side effects. Docetaxel proliposomes composed of docetaxel/Tween-80/Phospholipon 90H/cholesterol/citric acid at molar ratio of 0.18:0.09:3.78:3.78:91.17 were prepared by solid dispersion technique, and then were hydrated with NaHCO₃ solution to obtain docetaxel liposomes by effervescent technique. The stability of proliposomes containing docetaxel, characterization and evaluation of lung-targeting effect of docetaxel liposomes in rabbit were studied. Docetaxel proliposomes were stable at 6?±?2°C for at least 12 months. The particle size, zeta-potential, and entrapment efficiency of the resulted liposomes were 1011?±?22?nm, ?23.7?±?0.26?mv, and 90.12?±?0.36%, respectively. As far as the targeting parameters are concerned, the relative intake rate (R_e) and the ratio of peak concentration (C_e) of lung were 28.91 and 74.28, respectively. Compared with liver, spleen, and kidney, the ratios of targeting efficacy (T_e)_liposomes to (T_e)_injection of lung were increased by a factor of 3.16, 23.00, and 27.83, respectively. In conclusion, the negatively charged docetaxel liposomes with diameter of about 1 µm described in this study have favorable lung-targeting effect and are a promising lung-targeting carrier.     

Development of bioadhesive buccal tablets for felodipine and pioglitazone in combined dosage form: In vitro,ex vivo,and in vivo characterization

The purpose of the present research was to develop bioadhesive buccal tablets for Felodipine (FDP) and Pioglitazone (PIO), low bioavailability drugs, in a combined dosage form for the management of diabetes and hypertension. Buccal tablets were prepared by direct compression method using bioadhesive polymers hydroxypropyl methyl cellulose, sodium carboxymethyl cellulose, and carbopol, alone or in combination of two polymers, and were evaluated for physicochemical properties, swelling index, in vitro bioadhesion, in vivo residence time, in vitro drug release, and ex vivo permeation through porcine buccal membrane. Formulation (PF6) showed peak detachment force (3.12 N), work of adhesion (0.72 mJ), swelling index (196%), erosion (10.8%), in vivo residence time of 280?min, in vitro drug release (99.65% and 98.96% in 6?h for FDP and PIO, respectively) with higuchi model release profile and permeated 66.1 and 64.6 % with a flux of 0.118 and 0.331?mg/h/cm² of FDP and PIO through porcine buccal membrane. The bioavailability study for optimized formulation (PF6) in pigs showed 2.05- and 2.13-times statistically significant (p?<?0.05) improvement in bioavailability for FDP and PIO, respectively, after administration of buccal tablets compared to oral suspension. The ex vivo–in vivo correlation was found to have a biphasic pattern and followed type A correlation. The stability of the PF6 was studied and no significant changes were detected in drug content and in vitro release and ex vivo permeation through porcine buccal membrane after 6 months.     

Development of in situ gel for nasal delivery: design,optimization, in vitro and in vivo evaluation

Abstract

Context: The mucoadhesive gel formulations are helpful to prolong the residence time at the nasal absorption site and thereby facilitate the uptake of drug. Sumatriptan succinate has oral bioavailability of 15% and undergoes hepatic metabolism, hence it is suitable for nasal administration.

Objective: The objective of the investigation was to develop a mucoadhesive in situ gel to improve the bioavailability of the sumatriptan succinate.

Materials and methods: Deacetylated gellan gum was used as gelling agent. In situ gel was formulated by ion activation mechanism in simulated nasal fluid. A 3² factorial design was found suitable to optimize batch. In vivo study was carried out in Spraugue-Dawley rats, and drug was estimated in plasma by UPLC-MS.

Result: The optimized batch showed drug release of 98.57% within 5?h followed by Peppas model of drug release. Ex vivo studies on sheep nasal mucosa showed 93.33% within 5?h. In histopathological study, optimized batch was found to be safe and stable in accelerated stability study for three months. Optimized formulation, F7 has shown absolute bioavailability, which was found to be 164.70%. Drug targeting index for brain tissues was found to be 1.866.

Discussion: Concentration of the gelling polymer was compromised for satisfactory gel strength and an acceptable viscosity. The release depended on viscosity of formulation. Drug targeting index indicates sumatriptan can reach to brain via olfactory pathway.

Conclusion: In situ gel proved to be suitable for administration of sumatriptan succinate through nasal route. The ease of administration coupled with less frequent administration enhances patient compliance.     

Mucoadhesive bilayer buccal tablet of carvedilol-loaded chitosan microspheres: in vitro,pharmacokinetic and pharmacodynamic investigations

A multiple-unit system comprising mucoadhesive bilayer buccal tablets of carvedilol-loaded chitosan microspheres (CMs) was developed to improve bioavailability and therapeutic efficacy of carvedilol. Drug-loaded CMs were prepared by spray drying, evaluated for powder and particle characteristics, and optimized batch of CMs was compressed into bilayer buccal tablets using Carbopol. Tablets were evaluated for physicochemical parameters, in vitro drug release, in vivo pharmacokinetic and pharmacodynamic studies. Optimized formulation, CMT1 (CMT, chitosan microsphere tablet) showed maximum mucoadhesive force (50?±?1.84?dyne/cm²), exhibited 73.08?±?3.05% drug release and demonstrated zero-order kinetics with non-Fickian release mechanism. Pharmacokinetic studies in rabbits showed significantly higher C_max (71.26?±?6.45?ng/mL), AUC_0–10 (AUC, area under the curve 390.75?±?5.23?ng/mL/h) and AUC_0–∞ (664.72?ng/mL/h) than carvedilol oral tablet. Pharmacodynamic studies confirmed reduction in mean arterial pressure, heart rate, body weight and triglyceride on administration of bilayer buccal tablet compared to oral carvedilol tablet. Multiple-unit system exhibited enhanced bioavailability and sustained release of carvedilol, indicating its improved therapeutic potential for the treatment of hypertension.     

Sustained-release effervescent floating matrix tablets of baclofen: development, optimization and in vitro-in vivo evaluation in healthy human volunteers

Background and the purpose of the study

Baclofen, a centrally acting skeletal muscle relaxant, is indicated in the long-term treatment of spasticity. It is difficult to formulate baclofen sustained release dosage forms because its absorption on arrival to colon (or even before) is low or nonexistent. In the present investigation efforts were made to improve the bioavailability of baclofen by increasing the residence time of the drug through sustained-release matrix tablet formulation via gastroretentive mechanism.

Methods

Tablets were prepared by wet granulation technique. The influence of gas generating and gel forming agents, amount of baclofen and total weight of tablet on physical properties, in vitro buoyancy, floating lag time, drug release, DSC, X-ray studies were investigated. The release mechanisms were explored and explained by applying zero order, first order, Higuchi and Korsmeyer equations. The selected formulations were subjected to stability study for the period of three months.

Results

For all formulations, kinetics of drug release from tablet followed Higuchi''s square root of time kinetic treatment heralding diffusion as predominant mechanism of drug release. Formulations containing 20 mg and 40 mg (F-1 and F-7) showed similar release profiles. There was no significant change in the selected formulations, when subjected to accelerated stability conditions over a period of three months. X-ray imaging in six healthy human volunteers revealed a mean gastric retention period of 5.50±0.7 hrs for the selected formulation.

Conclusion

Stable, sustained release effervescent floating matrix tablets of baclofen could be prepared by wet granulation technique.