Formulation and evaluation of taste-masked oral disintegrating tablet containing tolterodine-loaded montmorillonite.

Background and purpose: The present study aimed to obtain a taste-masked oral disintegrating tablet (ODT) containing tolterodine tartrate (TT) intercalated into montmorillonite (MMT). Experimental approach: The TT-MMT hybrid was prepared by ion exchange reaction. The effect of the initial concentration of TT, MMT, temperature, and pH on the encapsulation efficiency (EE) % of the drug in MMT was evaluated. The selected TT-MMT hybrid was characterized by X-ray diffraction (XRD), Fourier transforms infrared (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Then, the optimized TT-MMT hybrid was incorporated in the ODT prepared by direct compression method and taste-masking assessment performed by a human test panel. Findings/Results: The EE% of TT was in the range of 22.67 to 71.06% in different formulations. It was found that increases in MMT concentration significantly increased EE%. DSC and XRD studies indicated that the TT was intercalated in the MMT interlayer space in an amorphous or molecular state. In-vitro release studies at pH 6.8 showed that the amount of the drug released from the TT-MMT hybrid was negligible for the first 3 min. The post-compression of ODT also showed satisfactory results in terms of friability, hardness, disintegration time, and taste. Conclusion and implications: MMT-ODT could be a suitable vehicle for the taste masking of TT, with the potential for use in patients with swallowing problems.

Formulation and physicochemical characterization of azithromycin-loaded cubosomes.

Background and purpose: Azithromycin (AZ) is a macrolide antibiotic that is soluble in saliva pH; its bitter taste can be well sensed, decreasing the ability of the patient to get the drug. Thus, handling such a bitter taste is challenging in developing the oral formulation. A wide range of methods has been applied to tackle this problem. Cubosomes are considered nanoparticles forming cubic three-dimensional structures with a taste-masking effect. This research aimed to apply cubosomes to mask AZ's bitter taste. Experimental approach: Cubosomes which contained AZ were obtained by applying the film hydration method. Design expert software (version 11) was then employed for optimizing cubosomes that contained the drug. The encapsulation efficiency, particle size as well as polydispersity index of drug-loaded cubosomes were then subjected to evaluation. Assessment of particle morphology was done through SEM. The antimicrobial qualities of AZ-loaded cubosomes were then assessed by utilizing the disc diffusion method. Then, the taste masking study was carried out by referring to human volunteers. Finding/Results: AZ-loaded cubosomes were spherical in terms of shape and in the 166-272 nm range, with a polydispersity index of 0.17-0.33 and encapsulation efficiency of 80-92%. The results related to the microbial culture revealed that the antimicrobial qualities related to AZ-loaded cubosomes were like those of AZ. The results obtained by taste evaluation also revealed that the cubosomes could well mask the drug's bitter taste. Conclusion and implications: These findings, thus, revealed that while the antimicrobial impact of AZ is not under the influence of loading in cubosomes, its taste could be well improved.

Preparation and characterization of Eudragit L 100-55/chitosan enteric nanoparticles containing omeprazole using general factorial design: in vitro/in vivo study.

BACKGROUND AND PURPOSE: Omeprazole (OMP) is broadly used for the treatment of gastroesophageal reflux and other acid-related diseases. The current study aimed to prepare enteric-coated nanoparticles containing OMP to achieve a stable powder formulation easily prescribed in children. EXPERIMENTAL APPROACH: The nanoparticles were formed by complex coacervation method using chitosan (CTS) and Eudragit L100/55 (EU) and the impact of various formulation variables (the concentrations of EU solution and its volume ratio to CTS solution) were assessed using 32 fractional design. The mean particle size (PS), zeta potential (ZP), encapsulation efficiency (EE), and drug loading (DL) were determined. Finally, the pharmacological effects of the optimized OMP enteric nanoparticles were evaluated by an in vivo antiulcer study using Sprague-Dawley rats. FINDINGS/RESULTS: The highest desirability value was for formulation F5 (containing EU concentration 4 mg/mL and EU/CTS volume ratio 2:1). PS, ZP, EE, and DL of the optimized OMP-loaded nanoparticles were confirmed 810 ± 14 nm, -38.2 ± 1.8 mV, 83.1± 4.2%, and 13.1± 1.5%, respectively. in vitro release studies showed the pH sensitivity of nanoparticles and OMP release was pH-dependent. in vivo pharmacological assessment revealed that the optimized formulation was able to protect rat stomach against ulcer formation induced by indomethacin compared to the group that received normal saline which demonstrated severe peptic ulcer and hemorrhagic spots. CONCLUSION AND IMPLICATION: Our results indicated that the enteric EU/CTS nanoparticles were successfully prepared via a complex coacervation method and their efficacy could be comparable with commercial OMP pellets.

Preparation and in vitro-in vivo evaluation of acyclovir floating tablets.

In the current study, floating dosage form containing acyclovir was developed to increase its oral bioavailability. Effervescent floating tablets containing 200 mg acyclovir were prepared by direct compression method with three different rate controlling polymers including Hydroxypropyl methylcellulose K4M, Carbapol 934, and Polyvinylpyrrolidone. Optimized formulation showed good floating properties and in vitro drug release characteristics with mean dissolution time and dissolution efficacy of about 4.76 h and 54.33%, respectively. X-ray radiography exhibited that the tablet would reside in the stomach for about 5 ± 0.7 h. After oral administration of floating tablet containing 200 mg acyclovir, the Cmax, Tmax , and AUC0-∞ of optimized gastroretentive formulation were found to be 551 ± 141 ng/mL, 2.75 ± 0.25 h and 3761 ± 909.6 ng/mL/h, respectively.

Synthesis and cytotoxicity evaluation of some new 6-nitro derivatives of thiazole-containing 4-(3H)-quinazolinone.

Quinazolinones are a group of fused heterocyclic compounds which have valuable biological properties including cytotoxic, antibacterial and antifungal activities. Thiazole group-containing compounds have been also reported to have a wide range of biological activities such as antitumor, anti-inflammatory, analgesic and antibacterial effects. Due to valuable cytotoxic effects of both thiazole groups and quinazoline derivatives, in this study a series of quinazolinone-thiazole hybrids were synthesized and evaluated for their cytotoxic effects on three cell lines including MCF-7, HT-29, and PC-3. Among tested compounds (quinazolinones and three intermediates), k5 and k6 showed highest cytotoxic activities against PC3 cell line. K6 and C were most active compounds against MCF7 and K6 showed best cytotoxicity on HT-29 cell line.

In vivo pharmacokinetics, biodistribution and anti-tumor effect of paclitaxel-loaded targeted chitosan-based polymeric micelle.

A water-insoluble anti-tumor agent, paclitaxel (PTX) was successfully incorporated into novel-targeted polymeric micelles based on tocopherol succinate-chitosan-polyethylene glycol-folic acid (PTX/TS-CS-PEG-FA). The aim of the present study was to evaluate the pharmacokinetics, tissue distribution and efficacy of PTX/TS-CS-PEG-FA in comparison to Anzatax® in tumor bearing mice. The micellar formulation showed higher in vitro cytotoxicity against mice breast cancer cell line, 4T1, due to the folate receptor-mediated endocytosis. The IC50 value of PTX, a concentration at which 50% cells are killed, was 1.17 and 0.93 µM for Anzatax® and PTX/TS-CS-PEG-FA micelles, respectively. The in vivo anti-tumor efficacy of PTX/TS-CS-PEG-FA, as measured by reduction in tumor volume of 4T1 mouse breast cancer injected in Balb/c mice was significantly greater than that of Anzatax®. Pharmacokinetic study in tumor bearing mice revealed that the micellar formulation prolonged the systemic circulation time of PTX and the AUC of PTX/TS-CS-PEG-FA was obtained 0.83-fold lower than Anzatax®. Compared with Anzatax®, the Vd, T1/2ß and MRT of PTX/TS-CS-PEG-FA was increased by 2.76, 2.05 and 1.68-fold, respectively. As demonstrated by tissue distribution, the PTX/TS-CS-PEG-FA micelles increased accumulation of PTX in tumor, therefore, resulted in anti-tumor effects enhancement and drug concentration in the normal tissues reduction. Taken together, our evaluations show that PTX/TS-CS-PEG-FA micelle is a potential drug delivery system of PTX for the effective treatment of the tumor and systematic toxicity reduction, thus, the micellar formulation can provide a useful alternative dosage form for intravenous administration of PTX.

A Rapid and Sensitive HPLC Method for Quantitation of Paclitaxel in Biological Samples using Liquid-Liquid Extraction and UV Detection: Application to Pharmacokinetics and Tissues Distribution Study of Paclitaxel Loaded Targeted Polymeric Micelles in Tumor Bearing Mice.

A simple, rapid, and sensitive reversed-phase HPLC method was developed and validated for determination of paclitaxel (PTX) in plasma, various organs and tumor tissues of tumor-bearing mice. Tissue specimens of liver, kidneys, spleen, lungs, heart and tumor were separately homogenized in normal saline. Plasma or tissue homogenate (250 µl) containing PTX and internal standard (diazepam) were extracted by diethyl ether (6 ml). The separation was achieved on a µ-Bondapak C18 HPLC column using sodium acetate buffer solution (0.01 M)/acetonitrile (58/42 v/v) at pH 5 ± 0.1 and flow rate of 1.9 mL/min. The effluent was monitored at 227 nm and column temperature was adjusted at 58ºC. The internal standard and PTX were eluted at 4.2 and 5.2 min, respectively and no interfering peaks were observed. Calibration curves were linear over the concentration range of 0.25-10 µg/ml of PTX in plasma and 0.3-20 µg/ml PTX in tissue homogenates with acceptable precision and accuracy (<15%). The mean recoveries of the drug after plasma extraction was 87.4% ± 3.6 while those of tissue homogenates ranged from 62.1± 4.5 to 75.5± 3.2 depending on the type of tissues studied. PTX was stable in samples with no evidence of degradation during 3 freeze-thaw cycles and 3 months storage at -70 °C. The developed HPLC method was applied to quantify PTX in the mouse plasma and tissues after intravenous administration of 10 mg equivalent PTX/Kg dose of PTX-loaded tocopherol succinate-chitosan-polyethylene glycol-folate (TS-CS-PEG-FA) micelles formulation or Anzatax® (Cremophor® EL- based formulation of PTX) to female Balb/c mice.

Development and in vitro/in vivo evaluation of a novel targeted polymeric micelle for delivery of paclitaxel.

In this study a novel receptor-targeted micelle delivery system based on tocopherol succinate-chitosan-polyethylene glycol-folic acid (TS-CS-PEG-FA) was synthesized and loaded with paclitaxel (PTX). Physicochemical properties of the micelles such as critical micelle concentration, micelle size, entrapment efficiency, stability, release properties, cellular uptake and in vitro cytotoxicity were investigated in detail. Furthermore, the pharmacokinetics and tissue distributions of PTX-loaded micelles were evaluated in Balb/c mice and compared with Anzatax(®) (PTX in Cremophor EL(®)). Particle sizes and zeta potentials of the micelles were in the range of 162.3-277.1 nm and 18.5-28.3 mV, respectively. The drug entrapment efficiencies of the micelles were within 53.6-82.5% (w/w). Cytotoxicity assay demonstrated increased cytotoxic activity of PTX-loaded TS-CS-PEG-FA micelles compared to free PTX. The Vd and t1/2ß of PTX-loaded TS-CS-PEG-FA were increased by 2.76- and 2.05-fold, respectively, while the plasma AUC of the micelles was only 0.76-fold lower than those of Anzatax(®) As demonstrated by tissue distribution, the PTX/TS-CS-PEG-FA micelles increased accumulation of PTX in tumor tissue. Therefore, the targeted chitosan derived micelle offered a stable and effective delivery system for PTX cancer chemotherapy.

Co-delivery of paclitaxel and α-tocopherol succinate by novel chitosan-based polymeric micelles for improving micellar stability and efficacious combination therapy.

The aim of this study was to develop chitosan derivative polymeric micelles for co-delivery of paclitaxel (PTX) and α-tocopherol succinate (α-TS) to the cancer cells to improve the therapeutic efficiency and reduce side effects of PTX. In this study, amphiphilic tocopheryl succinate-grafted chitosan oligosaccharide was synthesized and physically loaded by PTX and α-TS with entrapment efficiency of 67.9% and 73.2%, respectively. Physical incorporation of α-TS into the micelles increased the hydrophobic interaction between PTX and the micelles core, which improved micelle stability, reduced the micelle size and also sustained the PTX release from the micelles. The mean particle size and zeta potential of αTS/PTX-loaded micelles were about 133 nm and +25.2 mV, respectively, and PTX release was completed during 6-9 d from the micelles. Furthermore, the cytotoxicity of α-TS/PTX-loaded micelles against human ovarian cancer cell line cancer cell in vitro was higher than that of PTX-loaded micelles and the free drug solution. Half maximal inhibitory concentration values of PTX after 48-h exposure of the cells to the PTX-loaded micelles modified and unmodified with α-TS were 110 and 188 ng/ml, respectively.

Development, characterizations and biocompatibility evaluations of intravitreal lipid implants.

BACKGROUND: The treatment of posterior eye diseases is always challenging mainly due to inaccessibility of the region. Many drugs are currently delivered by repeated intraocular injections. OBJECTIVES: The purpose of this study was to investigate the potential applications of natural triglycerides as alternative carriers to synthetic polymers in terms of drug release profile and also biocompatibility for intraocular use. MATERIALS AND METHODS: In vitro/in vivo evaluations of intravitreal implants fabricated from the physiological lipid, glyceride tripalmitate containing clindamycin phosphate as a model drug was performed. The micro-implants with average diameter of 0.4 mm were fabricated via a hot melt extrusion method. The extrudates were analyzed using scanning electron microscopy, differential scanning calorimetry, and in vitro drug dissolution studies. For biocompatibility, the implants were implanted into rabbit eyes. Clinical investigations including fundus observations, electroretinography as well as histological evaluations were performed. RESULTS: In vitro tests guaranteed usefulness of the production method for preparing the homogenous mixture of the drug and lipid without affecting thermal and crystalinity characteristics of the components. In vitro releases indicated a bi-phasic pattern for lower lipid ratios, which were completed by the end of day three. With higher lipid ratios, more controlled release profiles were achieved until about ten days for a lipid ratio of 95%. Clinical observations did not show any abnormalities up to two months after implantation into the rabbit eye. CONCLUSIONS: These results suggest that although the implant could not adequately retard release of the present drug model yet, due to good physical characteristics and in vivo biocompatibility, it can represent a suitable device for loading wide ranges of therapeutics in treatment of many kinds of retinochoroidal disorders.

Development of a prolonged-release gastroretentive tablet formulation of ciprofloxacin hydrochloride: pharmacokinetic characterization in healthy human volunteers.

The fluroquinolone anti-biotic ciprofloxacin is primarily dissolved and absorbed from the upper part of the GI tract. We, therefore, aimed to develop a prolonged release gastroretentive (GT) formulation of ciprofloxacin that could be administered once daily with a conventional tablet (CT). A variety of polymers and effervescent properties were utilized to optimize the desired disposition profile. Tablets were prepared by the direct compression technique and evaluated for physical properties, swelling, floating, and drug release. In vivo studies were also carried out on the optimized GT formulation and CT in healthy volunteers. A very sensitive and reliable HPLC method was developed to measure plasma concentration of ciprofloxacin. The duration of floating times were predominantly >24 h and floating lag times <20 s. The drug release mechanism followed zero order kinetics. C(max), T(max), and AUC(0-∞) of GT vs CT were 0.945±0.29 vs 2.1±0.46 µg/ml, 6.0±1.42 vs 1.42±0.59 h and 8.54±1.87 vs 9.45±2.12 µg/ml/h, respectively. Pharmacokinetic parameters indicate that the developed GT formulation extended the pharmacokinetic profile achieved with CT. The C(max)/MIC and AUC(0-∞)/MIC, which are indicative of eradication of pathogens, following co-administration of GT with CT were comparable to those of twice-daily administration of CT alone.