Current Drug Delivery (v.13, #3)

Meet Our Editorial Board Member by Per Artursson (299-299).

Characterization of pDNA-TMC Nanoparticle Interaction and Stability by Johanna Poecheim, Viorica Patrulea, Christian Reichert, Gerrit Borchard (301-308).
Formulation of nanoparticulate DNA vaccines requires the assessment of stability and integrity of the components implicated. Stability of cationic nanoparticles made of N-trimethyl chitosan and chondroitin sulfate (TMC nanoparticles) was investigated in aqueous solution and after freeze-drying by characterization of their size, polydispersity index (PDI), and zeta potential. Furthermore, the structural integrity of plasmid DNA (pDNA) on adsorption to the nanoparticle surface was investigated. Agarose gel electrophoresis showed DNA retention when applied with the nanocarrier, suggesting that pDNA adsorption on nanoparticles took place. In circular dichroism (CD) spectra, ellipticity of pDNA decreased at 280 nm and increased at 245 nm, and the maximum wavelength shifted from 275 nm to 285 nm when nanoparticles were present. Once released from the particles, the secondary structure of the plasmid was retained in its native form. pDNA release from pDNA-TMC nanoparticles was indicated by a rise in zeta potential from initially -32 mV (pDNA adsorbed to particles) to 14 mV during one hour, and to 36 mV after 24 hours. Unloaded TMC nanoparticles remained stable in suspension for 24 hours, maintaining diameters of around 200 nm, and zeta potential values of approximately 38 mV. Freeze-drying with sucrose could ensure storage for 30 days, with minimal increase in size (291 nm) and charge (62 mV). In conclusion, TMC nanoparticles may potentially be freeze-dried in the presence of sucrose to be stored for prolonged periods of time. Furthermore, pDNA was successfully adsorbed to the cationic nanoparticles and remained intact after being released.

Bacteriophage (from 'bacteria' and Greek ?????? phagein "to devour" or bacterial eaters) are bacterial viruses that infect and kill bacteria. Bacteriophages (shortly “phages”) are among the most common and diverse entities in the biosphere. The estimated number of phages on earth is about 1032. Bacteriophages are often isolated from environmental sources, such as water samples, etc. Felix d'Herelle, one of the discoverers of bacteriophages, was the one who suggested them for therapy of human and animal bacterial infections. This idea was very popular in the world until the advent of antibiotics commercial after which production of therapeutic phages ceased in most of the Western countries, but not in the former Soviet Union. The application of antibiotics in the clinical practice, besides the well-known side effects, entails, in addition, the appearance of the forms of bacteria, resistant to newly synthesized preparations. It was concluded that a European and global strategy to address this gap is urgently needed. Now, faced with the alarming growth of a variety of antibiotic resistant bacterial infections, Western researchers and governments are giving phages a serious look. The phages nowadays are seen as a possible therapy against multi-drug-resistant strains of many bacteria. The therapeutic action of bacteriophages significantly differs from antibiotics, which makes them still active against multi-drug-resistant bacteria. Bacteriophages have a number of other advantages in comparison with antibiotics. First of all, they are efficient against multi-drug-resistant bacteria. The aim of this review was to provide an overview of the past and current experiences in the field of phage therapy in the countries where it has been traditionally applied in the clinical practice. Although the style and quality of old Soviet scientific publications dedicated to phage therapy are not challenging the international standards, there is still valuable information which may not be neglected by modern researchers. This information is especially important as it remained unavailable for the Western scientists before because of the language barriers until now. The goal of this article is to encourage further research on this topic, and facilitate rapid decisions on the development of appropriate regulations, which would ultimately permit the use of phages as therapeutic or preventative medicines in daily clinical practice in the Western countries where multiplying drug-resistant bacteria gradually becomes the greatest life threatening problem.

Is Boric Acid Toxic to Reproduction in Humans? Assessment of the Animal Reproductive Toxicity Data and Epidemiological Study Results by Yalç|n Duydu, Nur|en Ba|aran, Aylin Ustünda|, Sevtap Ayd|n, Ulkü Unde|er, Osman Yavuz Ataman, Kaan Aydos, Yalç|n Düker, Katja Ickstadt, Brita Schulze Waltrup, Klaus Golka, Hermann Maximilian Bolt (324-329).
Boric acid and sodium borates are classified as toxic to reproduction in the CLP Regulation under “Category 1B” with the hazard statement of “H360FD”. This classification is based on the reprotoxic effects of boric acid and sodium borates in animal experiments at high doses. However, boron mediated reprotoxic effects have not been proven in epidemiological studies so far. The epidemiological study performed in Band?rma boric acid production plant is the most comprehensive published study in this field with 204 voluntarily participated male workers. Sperm quality parameters (sperm morphology, concentration and motility parameters), FSH, LH and testosterone levels were determined in all participated employees as the reproductive toxicity biomarkers of males. However, boron mediated unfavorable effects on reproduction in male workers have not been determined even in the workers under very high daily boron exposure (0.21 mg B/kg-bw/day) conditions. The NOAEL for rat reproductive toxicity is equivalent to a blood boron level of 2020 ng/g. This level is higher than the mean blood boron concentration (223.89 ± 69.49 ng/g) of the high exposure group workers in Band?rma boric acid production plant (Turkey) by a factor of 9. Accordingly, classifying boric acid and sodium borates under “Category 1B” as “presumed reproductive human toxicant in the CLP regulation seems scientifically not reasonable. The results of the epidemiological studies (including the study performed in China) support for a down-classification of boric acid from the category 1B, H360FD to category 2, H361d, (suspected of damaging the unborn child).

3,5-diiodo-L-thyronine: A Possible Pharmacological Agent? by Maria Coppola, Federica Cioffi, Maria Moreno, Fernando Goglia, Elena Silvestri (330-338).
Overweight and obesity related metabolic disorders, commonly sharing a pathogenic excess of body adiposity, are world-wide epidemic leading to increasing morbidity and mortality. The related conditions include, among the others, liver steatosis, insulin resistance, and cardiovascular risk. Effective and safe anti-obesity drugs are still needed. Likely without undesirable side effects, an ideal treatment should be able to counteract the numerous causes associated with excess of body adiposity putatively modulating the delicate balance between feeding and energy expenditure, untimely controlling the adipose mass. In the past, thyroid hormones have been tested in reducing weight and lipid accumulation, however, the concomitant induction of a thyrotoxicosis state limited their use. Recent studies in rodents revealed that 3,5- diiodo-L-thyronine (T2), an endogenous metabolite of thyroid hormones, exhibits interesting metabolic activities. Specifically, when exogenously administered, T2 increases the resting metabolic rate and elicits short-term beneficial hypolipidemic effects, without being thyrotoxic, at lest in high fat diet fed rats. Now, a matter of interest is whether T2 can be considered or not a potential anti-obesity pharmacological agent. Actually, very few studies have been performed as far as it concerns the effects of T2 in humans and further analyses on larger cohorts to test time of use- and dose-dependent actions as well as the putative occurrence of T2 induced undesirable side effects, are needed. Here, an updated overview of the current literature on T2 bioactivity is furnished with a particular focus on those effects which may be defined “beneficial” vs. “deleterious” ones above all in view of its putative pharmacological use.

PEO-PPO-PEO/Poly(DL-lactide-co-caprolactone) Nanoparticles as Carriers for SN-38: Design, Optimization and Nano-Bio Interface Interactions by Rozafa Koliqi, Simona Dimchevska, Nikola Geskovski, Gjorgji Petruševski, Marina Chacorovska, Biljana Pejova, Delyan R. Hristov, Sonja Ugarkovic, Katerina Goracinova (339-352).
Encapsulation of extremely hydrophobic substances such as SN-38 into nanoparticles, is a promising approach to solve the solubility issue and enable drug administration. Moreover, nanocarriers' tumor homing behavior, targeted and controlled release at the site of action will optimize therapeutic potency and decrease toxicity of the incorporated drug substance. However, the enormous drug hydrophobicity might limit the capacity for encapsulation as the premature drug precipitation will contribute to fast free drug crystal growth, low drug incorporation and huge waste of the active material. In this article we defined the optimal region for manufacturing of SN-38 loaded PEO-PPO-PEO/P(DL)LCL nanoparticles (NPs) with high efficacy of encapsulation, suitable particle size and different surface properties, using D-optimal design and nanoprecipitation as production method. Further we made an approach to investigate the interactions with macromolecules at the nano-bio interface which are predetermined by the physico-chemical and surface properties of the NPs, and are important determinants for the biological identity of the nanoparticles, the potential for evasion of the physiological barriers and the efficacy of localization at the site of action. Here we present in depth analysis of the behavior of two types of nanoparticles with different surface properties through structured protein interaction and bioreactivity experiments in order to presuppose NP performance and toxicological profile in biological environment.

Therapeutic drug monitoring (TDM) is a valuable tool for tailoring the dosage of the prescribed medication(s) to the individual pharmacokinetic characteristics of a patient. In psychiatry and neurology, however, proven evidence that TDM should be used for treatment with the multiple neuropsychiatric medications is restricted to few compounds. Well-designed clinical trials on medical and economic benefits of TDM are rare. The use of TDM is limited in most countries to few antiepileptics, especially carbamazepine, phenobarbital and phenytoin, some mood stabilizers, especially lithium and valproic acid, some antidepressants, especially tricyclic antidepressants and some antipsychotics, primarily clozapine because these drugs have a narrow therapeutic index. On the other hand, specific indications and distinct problems can make TDM most useful for individualized pharmacotherapy with almost any neuropsychiatric drug. Potential benefits of TDM can, however, only be reaped if the method is adequately integrated into the clinical treatment process. The TDM expert group of the Arbeitsgemeinschaft fur Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) issued consensus guidelines for the best practice of TDM in psychiatry and neurology. A first version was published in 2004. These guidelines were extended in 2011 and are actually updated (see: www.agnp.de). Exemplified by single cases it is shown here how to use TDM consensus guidelines for problem solving in psychiatry and neurology. Studies on depressed patients give evidence for tricyclic antidepressants, venlafaxine and citalopram that TDM could become a standard of care in psychiatry and neurology. There is potential to accelerate improvement. Reducing phases of suffering will not only have medical benefits for the patients but also an impact on costs for the health system which needs to be clarified by controlled studies.

Development and Optimization of Self-emulsifying Drug Delivery Systems (SEDDS) for Enhanced Dissolution and Permeability of Rosuvastatin by H. Y. Karasulu, E. Gündo|du, T. Turgay, U. Ö. Türk, S. Apayd|n, I. Yild|r|m |im|ir, C. Yilmaz, E. Karasulu (362-370).
Rosuvastatin calcium is commonly used statin for treatment of dyslipidemia. It has low bioavailability. The aim of this study was to develop new rosuvastatin calcium self-emulsifying drug delivery systems (SEDDS) as an alternative formulation and to evaluate the permeability of rosuvastatin calcium SEDDS by using Caco-2 cells. Rosuvastatin calcium SEDDSs were developed by using pseudo ternary phase diagram and characterized by using heating cooling cycle, robustness to dilution, stability and in vitro drug release and permeability. The permeability studies of rosuvastatin calcium SEDDS (Papp (A?B) for F1-RS=1.492x10-5±0.413x10-5 and Papp (A?B) for F2-RS=1.254x10-5±0.19x10-5) across Caco-2 cells showed that permeability value from apical to basolateral was higher than permeability value of commercial formulation (Papp (A?B) =7.13x10-5±0.668x10-5). In conclusion, SEDDS as a drug carrier may be used as an effective and alternative hyperlipidemia therapy for oral delivery of rosuvastatin calcium.

Contribution of Electrochemistry to the Biomedical and Pharmaceutical Analytical Sciences by Jean-Michel Kauffmann, Stephanie Patris, Marie Vandeput, Ahmad Sarakbi, Abdul Karim Sakira (371-377).
All analytical techniques have experienced major progress since the last ten years and electroanalysis is also involved in this trend. The unique characteristics of phenomena occurring at the electrode-solution interface along with the variety of electrochemical methods currently available allow for a broad spectrum of applications. Potentiometric, conductometric, voltammetric and amperometric methods are briefly reviewed with a critical view in terms of performance of the developed instrumentation with special emphasis on pharmaceutical and biomedical applications.

Bioactive Secondary Metabolites from a Thai Collection of Soil and Marine-Derived Fungi of the Genera Neosartorya and Aspergillus by War War May Zin, Chadaporn Prompanya, Suradet Buttachon, Anake Kijjoa (378-388).
Background: Fungi are microorganisms which can produce interesting secondary metabolites with structural diversity. Although terrestrial fungi have been extensively investigated for their bioactive secondary metabolites such as antibiotics, marine-derived fungi have only recently attracted attention of Natural Products chemists.
Methods: Our group has been working on the secondary metabolites produced by the cultures of the fungi of the genera Neosartorya and Aspergillus, collected from soil and marine environments from the tropical region for the purpose of finding new leads for anticancer and antibacterial drugs.
Results: This review covers only the secondary metabolites of four soil and six marine-derived species of Neosarorya as well as a new species of marine-derived Aspergillus, investigated by our group. In total, we have isolated fifty three secondary metabolites which can be categorized as polyketides (two), isocoumarins (six), terpenoids (two), meroterpenes (fourteen), alkaloids (twenty eight) and cyclic peptide (one). The anticancer and antibacterial activities of these fungal metabolites are also discussed.
Conclusion: Among fifty three secondary metabolites isolated, only the alkaloid eurochevalierine and the cadinene sesquiterpene, isolated from the soil fungus N. pseudofisheri, showed relevant in vitro cytostatic activity against glioblastoma (U373) and non-small cell lung cancer (A549) cell lines while the meroditerpene aszonapyrone A exhibited strong antibacterial activity against multidrug-resistant Gram-positive bacteria and also strong antibiofilm activity in these isolates.

This review will focus on newest results leading to the discovery of new bioactive saponins by using a combination of successive advanced procedures in extraction, isolation, structure elucidation and bioassays. Microwave- and ultrasonic-assisted extractions, two recent advanced methods have been increasingly used in the last decade. Then, a multistep purification procedure was achieved by flash chromatography, vacuum liquid chromatography, low, medium- and high-pressure liquid chromatography on silica gel and reversed-phase silica gel RP-18 (VLC, LPLC, MPLC, HPLC). These successive chromatographic steps have been implemented in the author's laboratory in order to avoid the time-consuming traditional partitions between butanol and water, dialysis procedures or precipitations in diethyl/ether. The structural elucidation of complex saponins possessing from 5 to 8 sugar units is performed by a combination of extensive spectroscopic techniques including 1D- and 2D-NMR experiments (1H, 13C, DEPT, COSY, NOESY, TOCSY, HSQC, HMBC) and mass spectrometry (FAB-MS HRESIMS). The bioassays have been mainly carried out in the field of cancerology and inflammation, two closely related areas, and also in the field of immunology with recent literature results on Quillaja saponins in order to explore some structure/activity relationships. The more recent results of the author's laboratory will be presented with examples of saponins from the tropical plant biodiversity (Pittosporaceae, Polygalaceae, Mimosaceae, Sapindaceae, Apiaceae, Dioscoreaceae, and Asparagaceae). Furthermore, some new trends reported in the literature will be briefly reviewed concerning dereplication, and metabolomic approachs which are currently of considerable importance in the field of natural product discovery.

In this paper, we reported the development of a micro-flow label-free impedimetric biosensor based on the use of thin-film interdigitated gold array microelectrodes (IDA) for the detection of carbohydrate antigen 125 (CA125). The immunosensor is developed through the electropolymerization of anthranilic acid (AA) on the surface of IDA electrodes followed by the covalent attachment of anti-CA125 monoclonal antibody. CA125 protein affinity reaction was then evaluated by means of electrochemical impedance spectroscopy (EIS). The sensor was characterized by electrochemical techniques and scanning electron microscopy (SEM). Using the optimized experimental conditions, the developed immunosensor showed a good analytical performance for CA125 detection from 0 to 100 U/mL with estimated limit of detection (LOD = 3Sblank/Slope) of 7 U/mL.

Cyclic Peptide Containing Hydrophobic and Positively Charged Residues as a Drug Delivery System for Curcumin by Amir Nasrolahi Shirazi, Naglaa Salem El-Sayed, Rakesh Kumar Tiwari, Kathy Tavakoli, Keykavous Parang (409-417).
Due to the low water solubility and hydrophobic nature of curcumin, an efficient cellular uptake is critical for its biological activity. We have previously developed a number of homochiral L-cyclic peptides containing arginine and tryptophan as cell-penetrating peptides. Among the synthesized peptides, [WR]5 containing five arginine and five tryptophan residues was found to be the most efficient one. Here, we have compared the application of [WR]5 to improve the intracellular uptake of curcumin by using both peptide-curcumin conjugate and physical mixture (peptide + curcumin) strategies. Flow cytometry results showed that the intracellular uptake of curcumin (50 ?M) was enhanced through the physical mixing with [WR]5 by 5.7 folds compared to that of curcumin alone in human leukemia (CCRFCEM) cells after 3 h. When [WR]5 was conjugated with curcumin, the intracellular uptake was enhanced by 4 fold. These data suggest that the physical mixture can work more efficiently in enhancing the cellular delivery of curcumin. Furthermore, the antiproliferative activity of curcumin was enhanced by 20% and ?13% through the physical mixture and the conjugate, respectively, in CCRF-CEM cells after 72 h.

Cellular signaling associated with cardiac ?-adrenergic receptors (?-AR) is composed of coupled mechanism among ? 1-/?2-AR and Gs proteins with contribution of constitutive ?3-AR coupling to Gi proteins. However, down-regulation of ?-ARs in the heart under pathological conditions is mediated with a signaling G proteins-included mechanism. Additionally, there are serious conflicting data on this field in literature yet. Although some of these conflictions are generally related with either experimental protocols for different approaches or different animal models. To treat cardiovascular disorders, generally, various types of ?-blockers are used while their action mechanisms are not fully known yet. Furthermore, although ?-blockers are generally used to block the activated ?-ARs, they can be used to scavenge free radicals under oxidative stress. Studies, in whole-system, organ or cellular levels, showed that some ?-blockers, including timolol, have protective-actions against increased oxidative stress in diseased heart via ROSscavenging. Additionally, it has been mentioned that some ?-blockers nicely prevented the development of heart failure in both experimental and clinical studies by restoring sarcoplasmic reticulum (SR) Ca2+ release channels, RyR2. Since diabetic cardiomyopathy is recognized due to its diminished responsiveness to ?1-AR agonist stimulation in the heart with an up-regulation of ? 3-AR, inducing a strong negative inotropic effect on left ventricular function, it has been shown that treatment of streptozotocin-diabetic rats with timolol provided a marked cardio-protection. Importantly, it has been also documented that timolol treatment-dependent cardio-protection in diabetic rats includes basically prevention of RyR2- hyperphosphorylation, which, in turn, block Ca2+-leakage from SR via scavenging oxidative agents to control redox-state of cardiomyocytes. This action of timolol in diabetic heart is very similar to other known antioxidants, such as N-acetylcysteine or selenium compounds. In this review article, antioxidant-like action of timolol in diabetic cardiomyopathy was summarized in way of comparison with the benefits obtained with other antioxidants in the similar animal model.

Development of a Suitable Dissolution Method for the Combined Tablet Formulation of Atorvastatin and Ezetimibe by RP-LC Method by Kose Ozkan Cansel, Esim Ozgur, Kurbanoglu Sevinc, Savaser Ayhan, Ozkan Sibel A, Ozkan Yalcin (424-432).
Pharmaceutical preparations of ezetimibe and atorvastatin are generally used to regulate the lipid level in blood. It decreases the secondary events for patients with high cholesterol and clinical cardiovascular disease such as non-fatal or fatal heart attack. There is no any pharmacopoeia method available for the dissolution testing recommended by the FDA. Development of dissolution tests method is very critical parameter especially for the pharmaceutical preparations that contain Class II drugs (slightly soluble, good permeable). In the proposed method, the effects of pH and surfactant on the dissolution of poorly water soluble combined drug therapy with a different pKa values in an in vitro environment is investigated. The content of our study was designed to answer these open-ended questions. The optimized test conditions achieved under sink conditions with USP apparatus 2 at a paddle rotation speed of 75 rpm and 900 ml in 0.01 M Acetate buffer (pH= 6.8) containing 0.45% SDS as a dissolution medium. Quantification of dissolution samples were analyzed with a new fully validated RP-LC method with UV detection at 242 nm.

Ofloxacin Loaded Electrospun Fibers for Ocular Drug Delivery: Effect of Formulation Variables on Fiber Morphology and Drug Release by Ay|egül Karata|, Aslihan Hilal Algan, Nursel Pekel-Bayramgil, Fatih Turhan, Nurten Altanlar (433-443).
Ofloxacin (OFL) loaded poly(?-caprolactone) (PCL) and PCL: poly(butylene succinate) PBS fibers as a drug delivery system in the treatment of ocular infections were prepared by electrospinning. In particular, the effect of some formulation variables including polymer:drug ratio (9:1, 8:2 and 7:3 w/w), solvent systems like dichloromethane (DCM), N,N-dimethylformamide (DMF), N,Ndimethylacetamide (DMAc) and dimethylsulfoxide (DMSO), polymer blends of PCL:PBS at 80:20, 60:40 and 40:60 ratios on fiber morphology, fiber size were investigated. The morphology and diameter of the electrospun fibers were investigated by scanning electron microscopy (SEM) images also the thermal properties were evaluated by differential scanning calorimetry (DSC). The drug release behaviour from fibers and in vitro antibacterial activity were also studied. It was noticed that the average fiber diameter decreased with decreasing polymer amount in initial composition meanwhile the release of drug increased with increasing amount of drug in formulations. Solvent system of DCM:DMF at 80:20 ratio improved fiber morphology and resulted in a reduction in fiber diameter. It was found that smooth surface, flexible fibers with uniform morphology were obtained with 80:20 ratio of PCL:PBS compositions. All fibers showed a burst release of OFL. The initial amount of the released OFL was found to vary as a function of PCL:OFL ratio and polymer composition in the fiber. The microbiological activity of optimized formulation was evaluated using P. aeruginosa, S. epidermidis, S. Aureus and E. coli strains and the results of this study clearly demonstrated that freely released OFL from fibers inhibited the growth of the tested bacteria. The process of electrospinning had no adverse effect on the activity of incorporated drug in fibers.

Characterization and Antioxidant Activity of Quercetin/Methyl-?-Cyclodextrin Complexes by Kadri Güleç, Müzeyyen Demirel (444-451).
Quercetin (Qu), a polyphenolic flavonoid, is one of the most effective plant originated antioxidants. Despite the potential use of Qu in clinical trials, low water solubility, stability problems and the scarcity of cellular bioavailability limit its applications. The purpose of this study was to enhance aqueous solubility, dissolution rate and antioxidant activity of Qu by complexation with Methyl-?- cyclodextrin (M-?-CD). Analyses results showed that the aqueous solubility, dissolution rate and antioxidant activity of the complex were increased 254-fold, ~3-fold and 10% respectively compared to the pure Qu. Complexes were prepared by freeze-drying and evaporation method. The characteristics of the complexes were evaluated by DSC, XRD, 1H-NMR, FT-IR, SEM, encapsulation efficacy, in-vitro dissolution rate analyses. Antioxidant activity studies on complexes carried out with DPPH tests. Analyses results showed that the formation of the complexes resulted in enhanced solubility with increased its antioxidant activity of Qu.

Development of Itraconazole Liquisolid Compact: Effect of Polyvinylpyrrolidone on the Dissolution Properties by Wei Gong, Yuli Wang, Lei Sun, Jiahui Yang, Li Shan, Meiyan Yang, Chunsheng Gao (452-461).
The aim of this work was to utilize the liquisolid technique to enhance dissolution of itraconazole (ITZ). Liquisolid tablets of ITZ were formulated by using N-methyl-2-pyrrolidone as liquid vehicle, polyvinylpyrrolidone (PVP) as a precipitation inhibitor and magnesium aluminometasilicate Neusilin® as a carrier and coating material. The effect of PVP level on stability of liquid medication, physicomechnanical properties and dissolution rate of liquisolid compacts was studied in detail. The crystallinity of formulated drug and the interaction between excipients were examined by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). All the liquisolid tablets showed higher drug dissolution rates than the conventional, directly compressed tablets. The flowability of liquisolid powders was slightly improved as the proportion of PVP in ITZ-NMP mixture increased. Moreover, the stability of liquid medication and wetting ability of liquisolid tablets were improved by PVP. The presence of low amount of PVP (? 1%) in liquisolid formulation could enhance dissolution of ITZ liquisolid tablets, whereas the percentage of PVP over 5% decreased the dissolution of ITZ from liquisolid tablets. Both DSC and XRPD suggested reduction or loss of ITZ crystallinity upon liquisolid formulations indicating that the drug was almost solubilized and molecularly dispersed with excipients within the liquisolid matrix. It could be shown that increased solubility, wetting properties and surface area available for dissolution contributed to the improvement of the dissolution of ITZ from liquisolid tablets.

Bioavailability Enhancement of Rizatriptan Benzoate by Oral Disintegrating Strip: In vitro and In vivo Evaluation by S. T. Bhagawati, Ankita D. Chonkar, Swapnil J. Dengale, Sreenivasa M. Reddy, Krishnamurthy Bhat (462-470).
Oral disintegrating strips containing rizatriptan benzoate, a selective 5-hydroxy tryptamine receptor agonist with anti migraine property, was developed using polyvinyl alcohol, sodium alginate and hydroxyl propyl methylcellulose as the base materials. The analytical and bioanalytical methods were developed and validated using HPLC (PDA and flouroscence detectors). The dissolution study performed on the strips revealed that all the five formulations, release the drug within eight minutes. Under ICH accelerated stability conditions, strips were stable at 40°C and 75% humidity for eight weeks. Furthermore, pharmacokinetic properties of oral strip were compared with rizatriptan benzoate marketed tablet. Oral disintegrating strip and tablet showed significantly higher bioavailability. Oral strip exhibited better pharmacokinetic parameters than rizatriptan marketed tablet. The Tmax, Cmax, AUC and t1/2 for oral strip were found to be 1.00 h, 64.13±19.46 ng/mL, 352.00±71.57 ng/mL/h and 3.09±1.03 h respectively, whereas, tablet showed 1.5 h, 38.00±13.43 ng/mL, 210.38± 40.37ng/mL/h and 1.66±0.31 h respectively. These findings confirm that the rizatriptan benzoate oral disintegrating strip is potentially a useful tool for an effective treatment of migraine with improved bioavailability, rapid onset of action and with increased patient compliance.

Evaluation of Isolated Fractions of Aloe vera Gel Materials on Indinavir Pharmacokinetics: In vitro and in vivo Studies by Lonette Wallis, Maides Malan, Chrisna Gouws, Dewald Steyn, Suria Ellis, Efrem Abay, Lubbe Wiesner, Daniel P. Otto, Josias Hamman (471-480).
Aloe vera is a plant with a long history of traditional medicinal use and is consumed in different products, sometimes in conjunction with prescribed medicines. A. vera gel has shown the ability to modulate drug absorption in vitro. The aim of this study was to fractionate the precipitated polysaccharide component of A. vera gel based on molecular weight and to compare their interactions with indinavir pharmacokinetics. Crude polysaccharides were precipitated from a solution of A. vera gel and was fractionated by means of centrifugal filtration through membranes with different molecular weight cut-off values (i.e. 300 KDa, 100 KDa and 30 KDa). Marker molecules were quantified in the aloe leaf materials by means of nuclear magnetic resonance spectroscopy and the average molecular weight was determined by means of gel filtration chromatography linked to multi-angle-laser-light scattering and refractive index detection. The effect of the aloe leaf materials on the transepithelial electrical resistance (TEER) of Caco-2 cell monolayers as well as indinavir metabolism in LS180 cells was measured. The bioavailability of indinavir in the presence and absence of the aloe leaf materials was determined in Sprague-Dawley rats. All the aloe leaf materials investigated in this study reduced the TEER of Caco-2 cell monolayers, inhibited indinavir metabolism in LS 180 cells to different extents and changed the bioavailability parameters of indinavir in rats compared to that of indinavir alone. These indinavir pharmacokinetic modulation effects were not dependent on the presence of aloverose and also not on the average molecular weight of the isolated fractions.