Showing papers in "Drug Delivery in 2009"
TL;DR: The result of this study gave insight that the issue of ceftriaxone stability in oral formulation could be adequately addressed by tactical engineering of lipid drug delivery systems such as lipospheres.
Abstract: The aim of this study was to formulate and evaluate in vitro, ceftriaxone sodium lipospheres dispersions for oral administration. Ceftriaxone sodium lipospheres were prepared by melt-emulsification using 30%w/w Phospholipon® 90H in Softisan® 154 as the lipid matrix containing increasing quantities of PEG 4000 (10, 20, 30, and 40%w/w). Characterization based on particle size, particle morphology, encapsulation efficiency, loading capacity and pH were carried out on the lipospheres. Microbiological studies of the ceftriaxone sodium-loaded lipospheres were performed using Escherichia coli as the model organism. In vitro permeation of ceftriaxone sodium from the lipospheres through artificial membrane (0.22 μm pore size) was carried out using Franz cell and simulated intestinal fluid (SIF) without pancreatin as acceptor medium. Photomicrographs revealed spherical particles within a micrometer range with minimal growth after 1 month (Maximum size = 64.76 ± 3.81 μm). Microbiological studies indicated that lipos...
64 citations
TL;DR: It was found that carbopol could impart the nanoparticles with bioadhesive properties, improving the rentention and uptake of nanoparticles in the arterial wall, benefiting the nanoparticle for efficient localization of therapeutic agents in restenosis site.
Abstract: Local delivery of antiproliferative drugs encapsulated in biodegradable nanoparticles has shown promise as an experimental strategy for preventing vascular restenosis development. The general aim of this work was to develop polymeric nanoparticle carriers with bioadhesive properties, and to evaluate its adjuvant potential for local, intramural delivery of rapamycin for inhibition of restenosis. The bioadhesive rapamycin-loaded PLGA nanoparticles were obtained by applying carbopol 940 of different concentrations as stabilizer and bioadhesive agent. The resultant nanoparticles were characterized concerning physicochemical properties such as morphology, particle size, zeta potential, entrapment efficiency, drug loading, drug release in vitro, stability in vitro as well as the arterial uptake and retention ability in an ex-vivo model. The results revealed that carbopol could serve as a better stabilizer in the preparation of rapamycin-loaded PLGA nanoparticles compared with PVA, and the physicochemical characteristics of the obtained PLGA nanoparticles were affected by the concentration of carbopol. Furthermore, it was found that carbopol could impart the nanoparticles with bioadhesive properties, improving the rentention and uptake of nanoparticles in the arterial wall, benefiting the nanoparticles for efficient localization of therapeutic agents in restenosis site. Cell viability assay results showed that blank PLGA-carbopol nanoparticles exhibited low toxicity and excellent biocompatibility and rapamycin-loaded nanoparticles with a smaller particle size (< 200 nm) had an increased antiproliferative effect on cells in comparison to free drug. These results indicated that this research might provide a potential experimental basis for the further study of carbopol stabilized bioadhesive nanoparticles against restenosis in vivo.
61 citations
TL;DR: Investigation of lipophilic and hydrophilic components of CBZ from matrix tablet formulations suggest that wet granulation followed by compression could be a suitable method to formulate sustained release CBZ tablets.
Abstract: The objective of this study was to investigate the effect of lipophilic (Compritol® 888 ATO) and hydrophilic components (combination of HPMC and Avicel) on the release of carbamazepine from granules and corresponding tablet. Wet granulation followed by compression was employed for preparation of granules and tablets. The matrix swelling behavior was investigated. The dissolution profiles of each formulation were compared to those of Tegretol® CR tablets and the mean dissolution time (MDT), dissolution efficiency (DE%), and similarity factor (f2 factor) were calculated. It was found that increase in the concentration of HPMC results in reduction in the release rate from granules and achievement of zero-order is difficult from the granules. The amount of HPMC plays a dominant role for the drug release. The release mechanism of CBZ from matrix tablet formulations follows non-Fickian diffusion shifting to Case II by the increase of HPMC content, indicating significant contribution of erosion. Increasing in drug loading resulted in acceleration of the drug release and in anomalous controlled-release mechanism due to delayed hydration of the tablets. These results suggest that wet granulation followed by compression could be a suitable method to formulate sustained release CBZ tablets.
55 citations
TL;DR: Findings imply that these polyelectrolyte-coated alginate microspheres show promise as release systems to improve biocompatibility and prolong lifetime of implantable glucose sensors.
Abstract: Alginate microspheres loaded with dexamethasone were prepared by the droplet generator technique. Important parameters affecting drug release, including initial drug content, the type of polyelectrolyte coating, and a combination of different ratios of coated and uncoated microspheres were investigated to achieve in vitro dexamethasone delivery with approximately zero order release kinetics, releasing up to 100% of entrapped drug within 1 month, wherein dexamethasone released at a steady rate of 4.83 μg/day after an initial burst release period. These findings imply that these polyelectrolyte-coated alginate microspheres show promise as release systems to improve biocompatibility and prolong lifetime of implantable glucose sensors.
50 citations
TL;DR: The results suggest that the formulation of TIZ with an appropriate penetration enhancer may be useful in the development of a therapeutic system to deliver TIZ across the skin for a prolonged period, i.e. 24 hr.
Abstract: The effects of chemical enhancers and sonophoresis on the transdermal permeation of tizanidine hydrochloride (TIZ) across mouse skin were investigated. Parameters including drug solubility, apparent partition coefficient (APC), drug permeation, and degradation in skin were determined. Low frequency ultrasound was also applied in the presence and absence of chemical enhancers to assess whether drug permeation improved. APC values indicated that TIZ preferentially partitions into intercellular spaces and does not form a reservoir, with the drug also exhibiting good enzymatic stability in skin. Most of the enhancers studied significantly increased the permeation rate of TIZ through full thickness mouse skin in comparison with TIZ formulated in phosphate buffer. Maximum enhancement was observed for TIZ formulated as a suspension in 50% v/v aqueous ethanol containing 5% v/v citral. Sonophoresis significantly (p < 0.05) increased the cumulative amount of TIZ permeating through the skin at 15 and 30 min in comparison to passive diffusion. A synergistic effect was noted when sonophoresis was applied in the presence of chemical enhancers. The results suggest that the formulation of TIZ with an appropriate penetration enhancer may be useful in the development of a therapeutic system to deliver TIZ across the skin for a prolonged period, i.e. 24 hr. The application of ultrasound in association with chemical enhancers, such as the combination of 5% v/v citral in 50% v/v aqueous ethanol, could further serve as a non-oral and non-invasive drug delivery modality for the immediate therapeutic effect of muscle relaxants such as TIZ.
49 citations
TL;DR: Controlled release in situ gels consisting of carbopol and cellulose derivatives showed an increase in viscosity, gelling capacity, and adhesiveness as the concentration of each polymeric component was increased.
Abstract: The objective of the present study was to design controlled release ophthalmic delivery systems for ciprofloxacin based on polymeric carriers that undergo sol-to-gel transition upon change in pH or in the presence of cations in an attempt to prolong the effect of ciprofloxacin and improve its ocular bioavailability. Carbopol and alginates polymers were used to confer gelation properties to the formulations. Hydroxypropyl methylcellulose and methylcellulose were combined with carbopol to increase the viscosity of the gels and to reduce the concentration of the incorporated carbopol. The release exponents (n) for the designed systems were close to 1, indicating that the drug release occurred by zero-order kinetics. Controlled release in situ gels consisting of carbopol and cellulose derivatives showed an increase in viscosity, gelling capacity, and adhesiveness as the concentration of each polymeric component was increased. On the other hand, these parameters possessed lowest values when alginate was used a...
42 citations
TL;DR: Results suggest that a microneedle can be an ideal tool for transdermal delivery products and reduce the need for permeation enhancers.
Abstract: Non-invasive transdermal delivery using microneedle arrays was recently introduced to deliver a variety of large and hydrophilic compounds into the skin, including proteins and DNA. In this study, ...
33 citations
TL;DR: Findings suggest that Pgp-mediated MDR in cancer cells may be more effectively modulated by optimizing the composition of liposomes for loading PGP-substrate anti-cancer drugs.
Abstract: Multidrug resistance (MDR) caused by high expression of P-glycoprotein (Pgp) in cancer patients remains one of the major obstacles to successful therapy of cancer. Earlier studies have shown that the incorporation of Pgp-substrate drugs in liposomes may provide a strategy to circumvent Pgp-mediated drug efflux. The present study investigated the impact of liposome composition on the efflux of Pgp-substrate incorporated in liposomes. Liposomes with varying compositions were loaded with rhodamine 123, a fluorescent probe frequently used as a Pgp-substrate, and the retention of rhodamine was compared in two breast cancer cell lines: wild-type cells with no detectable Pgp expression (MCF-7/WT) and Pgp-expressing cells resulting from stable transfection of the MDR1 gene (MCF-7/Pgp). Pgp-expression decreased the rhodamine retention in MCF-7 cells, suggesting that Pgp is functional. Liposome loading increased rhodamine retention in MCF-7/Pgp cells, but not in MCF-7/WT cells. Surface charge of liposomes did not affect the rhodamine retention, whereas the incorporation of cholesterol and polyethyleneglycol-attached lipids was effective in further increasing the rhodamine retention in MCF-7/Pgp cells. Since further study demonstrated that the rate of rhodamine release from liposomes tended to be inversely correlated with rhodamine retention by cells, it seems likely that more rigid liposomes are able to sequester rhodamine more efficiently, thereby inhibiting direct interactions of rhodamine with Pgp proteins. Taken together, these findings suggest that Pgp-mediated MDR in cancer cells may be more effectively modulated by optimizing the composition of liposomes for loading Pgp-substrate anti-cancer drugs.
31 citations
TL;DR: Uptake, intracellular localization, cytotoxicity, and biological activity of siRNA were significantly dependent on the kind of CPP used and the length of the cationic peptides in the conjugate.
Abstract: To achieve the effective intracellular delivery of siRNA and silence specific genes, various types of conjugates between cell-penetrating peptides (CPPs; Transportan, Penetratin, Tat) and cationic peptides were developed. Uptake, intracellular localization, cytotoxicity, and biological activity of siRNA were significantly dependent on the kind of CPP used and the length of the cationic peptides in the conjugate. Transportan-based conjugates yielded both high internalization of siRNA and strong gene silencing activity, while Penetratin- and Tat-based conjugates did not. These different properties of CPPs emphasize the importance of careful peptide selection and design when attempting the application of CPP technology.
30 citations
TL;DR: At ratio of 10:50 PEI-Tat/E7DNA (w/w), both humoral and cellular immune responses were significantly enhanced as compared with E7DNA construct and induced Th1 response, which could have promising applications in gene therapy.
Abstract: DNA vaccination is a promising approach for inducing both humoral and cellular immune responses. The mode of plasmid DNA delivery is critical to make progress in DNA vaccination. Using human papillomavirus type 16 E7 as a model antigen, this study evaluated the effect of peptide-polymer hybrid including PEI600-Tat conjugate as a novel gene delivery system on the potency of antigen-specific immunity in mice model. At ratio of 10:50 PEI-Tat/E7DNA (w/w), both humoral and cellular immune responses were significantly enhanced as compared with E7DNA construct and induced Th1 response. Therefore, this new delivery system could have promising applications in gene therapy.
30 citations
TL;DR: Micellar DM-PIT-1 micellar preparations can be used for targeted combination therapy against TRAIL-resistant cancers and demonstrated high in vitro cytotoxicity against various cancer cells.
Abstract: The purpose of this study was to develope and characterize a micellar formulations of N-{[(2-hydroxy-5- nitrophenyl)amino]carbonothioyl}-3,5-dimethylbenzamide (DM-PIT-1)—a new small molecule non-lipid antagonist of phopshotidylinositol-3.4.5-triphopshate and inhibitor of the PI3-kinase pathway. Micelle-forming PEG2000-PE was used to solubilize DM-PIT-1. To improve the specificity of the micellar DM-PIT-1, cancer-targeting anti-nucleosomal mAb2C5 antibodies as well as Tumor necrosis factor- Related Apoptosis-Inducing Ligand (TRAIL) were attached to the surface of polymeric micelles. DM-PIT-1 was effectively incorporated (> 70%) into 14–16 nm micelles, which had a negative surface zeta potential of 4–5 mV. Micellar DM-PIT-1 demonstrated high in vitro cytotoxicity against various cancer cells. An improved potency of the dual-activity DM-PIT-1/TRAIL combination nanoparticles in inducing death of TRAIL-resistant cancer cells was shown. Efficacy of the TRAIL therapy was enhanced by combining it with the 2C5 ant...
TL;DR: The ability of MSM to deliver EDTA into an eye provides an opportunity for regional chelation therapy and these studies suggest that MSM could also be an adjuvant for delivering ciprofloxacin and other chemical compounds to specific, local tissue sites.
Abstract: Pharmacologic chelators do not effectively penetrate cell membranes and blood-brain barrier. This study assesses methylsulfonylmethane (MSM) as a permeability enhancer and an excipient to facilitate EDTA transport across biologic membranes, and to make possible localized, regional chelation. Topical application of MSM with C(14)EDTA onto the rat cornea led to uptake of the C(14)EDTA in all tested ocular tissues. Without MSM, EDTA did not penetrate the eye. The ability of MSM to deliver EDTA into an eye provides an opportunity for regional chelation therapy. Additionally, these studies suggest that MSM could also be an adjuvant for delivering ciprofloxacin and other chemical compounds to specific, local tissue sites.
TL;DR: The anesthetic activity of mucoadhesive LDC-CHG hydrogels was assessed in vivo after application on the buccal mucosa, compared to commercial semisolid formulations containing the same drug.
Abstract: Hydrogels for the buccal application of the anesthetic drug lidocaine hydrochloride (LDC) were prepared using chitosan glutamate (CHG), a soluble salt of chitosan, or a binary mixture of CHG and glycerin, at different weight ratios. The in vitro drug release was studied at the pH value of saliva to assess the effect of the different formulations on drug delivery. The anesthetic activity of mucoadhesive LDC-CHG hydrogels was assessed in vivo after application on the buccal mucosa, compared to commercial semisolid formulations containing the same drug. LDC-loaded hydrogels can be proposed for the symptom relief of aphthosis or other painful mouth diseases.
TL;DR: The NaCMC gel formulation of MTC with mucoadhesive properties with increased permeation rate is promising for prolonging nasal residence time and thereby nasal absorption.
Abstract: Nasal drug delivery is an interesting route of administration for metoclopramide hydrochloride (MTC) in preventing different kind of emesis. Currently, the routes of administration of antiemetics are oral or intravenous, although patient compliance is often impaired by the difficulties associated with acute emesis or invasiveness of parenteral administration. In this perspective, nasal dosage forms (solution, gel, and lyophilized powder) of MTC were prepared by using a mucoadhesive polymer sodium carboxymethylcellulose (NaCMC). In vitro and ex vivo drug release studies were performed in a modified horizontal diffusion chamber with cellulose membrane and excised cattle nasal mucosa as diffusion barriers. The tolerance of nasal mucosa to the formulation and its components were investigated using light microscopy. In vivo studies were carried out for the optimized formulations in sheep and the pharmacokinetics parameters were compared with oral solution and IV dosage form. The release of MTC from solution an...
TL;DR: The results of transfection showed that Folate-chitosan–CHETA−Sln enhanced the reporter gene expression against a folate receptor over-expressing cell line (SKOV3 cells) and did not induce obvious cytotoxicity against HEK 293 cells.
Abstract: Compared to viral carriers, non-viral gene delivery systems showed good biocompatibility and safety, but low transfection efficiencies. Fortunately, the mechanism of folic acid uptake by cells to promote targeting and internalization could improve transfection rates. In this study, folate-chitosan and one kind of cholesterol derivatives CHETA (Cholest-5-en-3beta-yl[2-[[4-[(carboxymethyl)dithio]-1-iminobutyl]amino]ethyl] carbamate, C(36)H(61)N(3)O(4)S(2)) were synthesized to prepare the charge changing Solid Lipid Nanoparticles (Folate-chitosan-CHETA-Sln) by a reverse micelle-double emulsion method. The resulted particles showed the distributions of size and zeta potential were 254.5 +/- 20 nm and -40.5 +/- 0.8 mV, respectively. The image observed by scanning electron microscopy (SEM) showed that Folate-chitosan-CHETA-Sln was spherical in shape. Moreover, after reaction with a disulfide reducing agent dithiothreitol (DTT), the zeta potential changed from negative to positive (20.5 +/- 1.9 mV). The results of transfection showed that Folate-chitosan-CHETA-Sln enhanced the reporter gene expression against a folate receptor over-expressing cell line (SKOV3 cells) compared to a folate receptor deficient cell line (A549 cells) and did not induce obvious cytotoxicity against HEK 293 cells. In addition, the presence of serum did not affect the transfectivity of Folate-chitosan-CHETA-Sln complexes. In conclusion, Folate-chitosan-CHETA-Slns with proper physical characteristics and high transfection efficiency might act as a novel non-viral gene delivery system.
TL;DR: It is suggested that the oral dry emulsion formulation could improve the intestinal absorption of AC by increasing its gastrointestinal absorption.
Abstract: A redispersible dry emulsion (DE) formulation of atorvastatin calcium (AC) was developed to enhance the in vitro dissolution of AC, thereby increasing its gastrointestinal absorption. The spray-drying technology was used where Plurol Oleique CC 497 was chosen as the oil phase. Effects of carriers, surfactants, and homogenizers on the characteristics of DE containing AC were systematically investigated. The final formulation consisted of dextrin and Poloxamer 188 as carrier and surfactant, respectively, and was homogenized by a high pressure homogenizer before spray drying. The in vitro release of AC from the optimized DE was significantly higher than that of pure AC powder (76% vs. 30% at 24 hr). The in vitro intestinal absorption of AC from the DE formulation was 0.77 microg/cm(2) at 2 hr, which was a 2.33-fold increase compared to the pure unformulated AC powder. These results suggest that the oral dry emulsion formulation could improve the intestinal absorption of AC.
TL;DR: This study evaluated thiolated poly(acrylic acid) nanoparticles as a valuable tool to protect insulin from degradation by serinproteases of the intestine and demonstrated that the obtained nanoparticles are capable of protecting 44.89% of the initial insulin amount from tryptic degradation, 21.33 ± 5.34% from chymotryptic degradation, and 45.01±1.40% from degradation in comparison to insulin solutions.
Abstract: This study evaluated thiolated poly(acrylic acid) nanoparticles as a valuable tool to protect insulin from degradation by serinproteases of the intestine. Nanaoparticles were characterized concerning particle size, zeta potential, and drug load. Furthermore, in vitro release studies were performed. Within in vitro degradation studies with trypsin, alpha-chymotrypsin, and elastase it could be demonstrated that the obtained nanoparticles are capable of protecting 44.47 +/- 0.89% of the initial insulin amount from tryptic degradation, 21.33 +/- 5.34% from chymotryptic degradation, and 45.01 +/- 1.40% from degradation by elastase compared to insulin solutions.
TL;DR: Labrasol may have potential clinical benefits in improving the ocular drug delivery of baicalin and has been investigated in vitro, using isolated rabbit corneas.
Abstract: Purpose: To investigate the use of Labrasol in ocular drug delivery system.Methods: The in vivo ocular irritation of Labrasol was tested by pathological section observation using rabbits. The effects of Labrasol on corneal permeability of baicalin was investigated in vitro, using isolated rabbit corneas. The pharmacokinetics was evaluated by microdialysis in the rabbit aqueous humors.Results: The results of the ocular irritation studies showed that Labrasol was non-irritant at the concentrations studied (0.5–3.0%(v/v)), while Labrasol produced slight irritation at a concentration of 5.0%(v/v). For the in vitro study, with Labrasol at concentrations of 1.5%, 2.0%, and 3.0%(v/v), the apparent permeability coefficient (Papp) was 1.69-, 3.14-, and 2.23- fold of baicalin solution, respectively. In the pharmacokinetics studies, the AUC value of baicalin solution with 2.0% and 3.0%(v/v) Labrasol were 4.7- and 5.6-fold of that of the control group (p < 0.01), and the Cmax value of baicalin solution with 2.0% and ...
TL;DR: A new method to prepare magnetite chitosan microspheres conjugated with methotrexate (MTX) for the controlled release of MTX as a magnetic targeting drug delivery system is developed.
Abstract: The purpose of the present study is to develop a new method to prepare magnetite chitosan microspheres conjugated with methotrexate (MTX) for the controlled release of MTX as a magnetic targeting drug delivery system. MTX was first conjugated to the chitosan chain via a peptide bond and then a suspension cross-linking technique was used for the production of magnetic chitosan microspheres with glutaraldehyde as the cross-linker. The MTX-loading capacity of the magnetic chitosan microspheres was determined and drug release experiments were also carried out to discuss the MTX release behavior. All the data support that the magnetic chitosan-MTX microspheres prepared in this method would have great potential application in magnetic targeting drug delivery technology.
TL;DR: The results of this investigation indicated rapid and larger extent of drug transport to the rat brain resulting in rapid induction of sleep followed by prolonged duration of sleep in rats following intranasal administration of mucoadhesive microemulsions.
Abstract: The aim of this investigation was to prepare and characterize microemulsions/mucoadhesive microemulsions of Diazepam (D), Lorazepam (L) and Alprazolam (A), evaluate their pharmacodynamic performances by performing comparative sleep induction studies in male albino rats to assess their role in effective management of insomnia patients. Microemulsions of Diazepam (DME), Lorazepam (LME) and Alprazolam (AME) were prepared by titration method and characterized for drug content, globule size distribution and zeta potential, nasal toxicity and sleep induction. DME, LME and AME were transparent and stable with mean globule size and zeta potential in the range of 95.6 nm to 141.7 nm and -2.205 to -0.111 mV respectively. The prepared microemulsions exhibited reversible nasal toxicity. Onset of sleep and duration of sleep were observed in the following order: Lorazepam > Alprazolam>Diazepam. Faster onset of sleep following intranasal administration of microemulsions ( 45 min) for all three drugs suggested selective nose-to-brain transport of drug(s). Intranasal administration of microemulsion based formulations resulted in even faster onset of sleep (<12 min) with intranasal mucoadhesive microemulsion(s) resulting in fastest onset of sleep (<9 min). Duration of sleep was longest with the intranasal mucoadhesive microemulsions. These results are suggestive of larger extent of distribution of drug(s) to brain after intranasal administration of mucoadhesive microemulsion(s). These results are further corroborated with by loss or rightening reflex and startle reflex at earlier time points (within 10 min and 15 min respectively) with mucoadhesive microemulsions. Thus, the results of this investigation indicated rapid and larger extent of drug transport to the rat brain resulting in rapid induction of sleep followed by prolonged duration of sleep in rats following intranasal administration of mucoadhesive microemulsion(s). However, the role of microemulsion based formulations developed in this investigation in clinical practice can only be established after animal studies in two different animal models followed by extensive clinical trials.
TL;DR: The testosterone may be used as an effective ligand for the site-specific delivery of anti-cancer agents to various ARs positive carcinomas.
Abstract: In the present investigation, testosterone (T) was evaluated as a targeting ligand to direct the site-specific delivery of 5-Fluorouracil (5-FU) bearing liposomes to the androgen receptor (ARs) positive tumors and other organs like prostate, brain, and testis. The testosterone was conjugated with the distearoyl phosphatidyl ethanolamine (DSPE) and then this lipid conjugate, Testosterone-DSPE (T-DSPE) was used as one of the components of the liposome. The liposomes were prepared by cast film method using T-DSPE, egg PC, and cholesterol. Further these liposomes were characterized for vesicle shape, average size, polydispersity index, drug entrapment, and in vitro drug release. It was observed that the prepared liposomes were spherical in shape with an average size of 232 ± 21 nm and 0.181 ± 0.064 polydispersity index. The in vitro drug release study showed 79.50 ± 2.81 percent drug release in 24 h. In vivo performance of the developed liposomes was evaluated using organ distribution study in male albino rat...
TL;DR: Initial evidence is provided for the potential use of iontophoresis for enhanced transdermal delivery of penbutolol sulfate in porcine ear skin throughIontophoretic transport and steady-state fluxes calculated from the linear portion of the cumulative amount versus time curves.
Abstract: Iontophoretic transport of penbutolol sulfate across porcine ear skin was studied. Passive transdermal flux of the drug in phosphate-buffered saline was 7.65 μg/cm2 hr. There was statistically significant flux enhancement when direct current iontophoresis was applied. Iontophoresis (0.11 mA/cm2, 0.17 mA/cm2, and 0.22 mA/cm2) for 6 hr, resulted in net transport of 87.36 μg/cm2, 137.51 μg/cm2, and 201.12 μg/cm2 of penbutolol sulfate, respectively. After 24 hr, cumulative amount of penbutolol transported were 201.63, 300.76, and 359.98 μg/cm2, respectively. There was a 2.20- (0.11 mA/cm2), 3.26- (0.17 m/Acm2), and 4.28-fold (0.22 mA/cm2) enhancement in transcutaneous steady-state flux values compared to passive delivery. Steady-state fluxes of penbutolol sulfate also increased proportionally to current density. Steady-state fluxes calculated from the linear portion of the cumulative amount versus time curves for penbutolol sulfate were 16.68, 24.97, and 32.76 μg/cm2/hr at current densities of 0.11, 0.17, and...
TL;DR: It has been demonstrated that spray-drying is a powerful method to prepare dry powders for pulmonary delivery and Fourier transform infra-red spectrum of powders indicated that the honokiol nanoparticles were successfully incorporated into microparticles.
Abstract: It has been demonstrated that spray-drying is a powerful method to prepare dry powders for pulmonary delivery. This paper prepared dispersible dry powders based on chitosan and mannitol containing honokiol nanoparticles as model drug. The results showed that the prepared microparticles are almost spherical and have appropriate aerodynamic properties for pulmonary delivery (aerodynamic diameters was between 2.8–3.3 μm and tapped density ranging from 0.14–0. 18 g/cm3). Moreover, surface morphology and aerodynamic properties of the powders were strongly affected by the content of mannitol. Fourier transform infra-red (FTIR) spectrum of powders indicated that the honokiol nanoparticles were successfully incorporated into microparticles. In vitro drug release profile was also observed. The content of mannitol in powders significantly influenced the release rate of honokiol from matrices.
TL;DR: Physicochemical properties, e.g. membrane rigidity, size distribution, surface potential, osmolarity, and viscosity, were determined for various liposomal lipid compositions and hydrating buffers to establish in vitro stability and in vivo fate.
Abstract: The major mechanism of removing cyanide from the body is its enzymatic conversion by a sulfurtransferase, e.g. rhodanese, to the less toxic thiocyanate in the presence of a sulfur donor. Earlier results demonstrated that externally administered encapsulated rhodanese significantly enhances the in vivo efficacy of the given sulfur donor. Present studies are focused on liposomal carrier systems encapsulating rhodanese. Physicochemical properties, e.g. membrane rigidity, size distribution, surface potential, osmolarity, and viscosity, were determined for various liposomal lipid compositions and hydrating buffers to establish in vitro stability and in vivo fate. Lipid composition was also optimized to achieve maximum encapsulation efficiency.
TL;DR: The release of the model drug from CD modified hydrogels show that especially covalently bonded β-cyclodextrin can change both the release rate and the release profile of ibuprofen.
Abstract: Hydrogels are water swollen networks of polymers and especially hydrogels consisting of poly vinylpyrrolidone/poly ethyleneglycol-dimethacrylate (PVP/PEG-DMA) blends show promising wound care properties. Enhanced functionality of the hydrogels can be achieved by incorporating drugs and other substances that may assist wound healing into the gel matrix. Controlling the release of active compounds from the hydrogels may be possible by carefully modifying the polymer matrix. For this purpose, cyclodextrins (CD) were grafted to the polymer matrix in 4–5 w/w% in an attempt to retard the release of water-soluble drugs. Ibuprofenate (IBU) was chosen as model drug and loaded in IBU/CD ratios of 0.6, 1.2, and 2.5. Vinyl derivatives of α-, β- and γ-CD were produced, added to the prepolymer blend and cured by UV-light. During this curing process the CD derivatives were covalently incorporated into the hydrogel matrix. The modified hydrogels were loaded with ibuprofenate by swelling. The release of the model drug fro...
TL;DR: The higher the pH of the phosphate buffered saline, the greater the amount of cumulative release of insulin-loaded NOCC nanoparticles, and thus they could protect insulin from acid.
Abstract: The aim of this research was to develop pH-sensitive insulin-loaded NOCC (N,O-carboxymethyl chitosan) nanoparticles for the controlled release of insulin via the oral route. Thus, in this study, insulin-loaded NOCC nanoparticles were prepared by ionic gelation of NOCC with TPP (tripolyphosphate). NOCC nanoparticles were formed at conditions of 2 mg/ml of NOCC and 1 mg/ml of TPP. It was found that the encapsulation efficiency and process yield decreased with increasing NOCC to TPP weight ratio. Furthermore, the cumulative release of insulin from insulin-loaded NOCC nanoparticles decreased with decreasing NOCC-to-TPP weight ratio, but it increased with decreasing the initial concentration of insulin. The higher the pH of the phosphate buffered saline, the greater the amount of cumulative release of insulin-loaded NOCC nanoparticles, and thus they could protect insulin from acid.
TL;DR: These biodegradable, self-assembling dextrin conjugates may be regarded as new potential complexing agents for hydrophobic drugs and, in particular, for fenretinide, to increase drug solubility, bioavailability, and thus therapeutic efficacy.
Abstract: This study relates to the preparation of a series of amphiphilic dextrins and their evaluation as complexing agents for anti-tumor hydrophobic drugs such as fenretinide, paclitaxel, etoposide, and camptothecin. The amphiphilic dextrins were obtained by conjugation of low molecular weight dextrin (average molecular weight 1670, average polymerization degree 9.33 glucose monomer) with hydrocarbon chains at substitution degree of about 0.1 mole hydrocarbon chain per mole of glucose monomer, as confirmed by 1H-NMR spectra. The conjugates were highly soluble in water and dissolved with formation of nano-aggregates endowed with hydrophobic inner cores able to host hydrophobic drugs by complexation. Complexation raised hydrophobic drugs aqueous solubility; the best results were obtained with fenretinide. Solid complexes with fenretinide were prepared by using three different approaches: the kneading method, the co-solubilisation method, and the co-precipitation method. Kneading method provided the complexes endowed with the best functional properties. Thermogravimetric analysis on solid samples suggested a notable thermal stability up to 300 degrees C for both the conjugated dextrins and the solid complexes. In differential scanning calorimetry profiles no significant differences were observed among amphiphilic dextrins and complexed drug, indicating that the guest molecule exists in an amorphous state in the solid matrices. Particle size analysis confirmed the dimensional suitability of the complexes for parenteral administration. Moreover, sustained drug release, in vitro, has been observed from all the complexes analyzed. Regarding the biological effects, the cytotoxicity of complexed fenretinide towards HTLA-230 neuroblastoma cell line was always higher than the free drug, suggesting that complexation increased drug bioavailability. These findings, taken together, indicated that these biodegradable, self-assembling dextrin conjugates may be regarded as new potential complexing agents for hydrophobic drugs and, in particular, for fenretinide, to increase drug solubility, bioavailability, and thus therapeutic efficacy.
TL;DR: In this article, the development and delivery properties of swellable drug-polyelectrolyte matrices prepared with complexes of the acid form of carboxymethylcellulose (HCMC) were obtained by neutralization of HCMC with two basic drugs.
Abstract: This article reports the development and delivery properties of swellable drug-polyelectrolyte matrices prepared with complexes of the acid form of carboxymethylcellulose (HCMC). Drug-polyelelectrolyte complexes (HCMC-D) were obtained by neutralization of HCMC with two model basic drugs (atenolol and metoclopramide). Characterization through FT-infrared spectroscopy, power X-ray diffraction, and DSC indicates the ionic nature of the interaction between the carboxylic groups of HCMC and the basic group of D. Matrices prepared by compacting (HCMC-D) alone or in a mixture with sodium carboxymethylcellulose were subjected to measurements of solvent up-take, dynamics of swelling, and release kinetics. Delivery rate of mixed matrices is a function of its composition and may be widely modulated. They exhibited anomalous delivery kinetics with Korsmeyer exponent n in the range 0.67–0.87. Experimental results indicate that the erosion of the hydrogel layer is the main delivery process.
TL;DR: The mannosylating group grafted into bilayer membrane resulted in a decrease in drug entrapment, owing to competitive binding, and the in vitro drug absorptions through everted sacs of mice ileum of both ManN-ACV-lip and PAM-ACv-lip were significantly higher than those of conventional ACV liposomes or suspension.
Abstract: The aim of this study was to develop mannosylated liposomes as bioadhesive carriers for oral drug delivery. Two kinds of acyclovir (ACV)-entrapped mannosylated liposomes, i.e. ManN-ACV-lip and PAM-ACV-lip, were prepared by the use of mannosamine HCl (ManN) and p-aminophenyl-alpha-D-mannopyranoside (PAM), respectively. The mean sizes, drug entrapment efficiency, and loading capacity values of all liposomal formulations were in the ranges of 233-371 nm, 82-95%, and 42-47%, respectively. The mean size of PAM-ACV-lip was significantly smaller than those of conventional ACV liposomes and ManN-ACV-lip due to the more conical packing parameter of mannose-conjugated phospholipid. The mannosylating group grafted into bilayer membrane resulted in a decrease in drug entrapment, owing to competitive binding. The in vitro drug absorptions through everted sacs of mice ileum of both mannosylated ACV liposomes were significantly higher than those of conventional ACV liposomes or suspension.
TL;DR: Development and study of the stability of transdermal methimazole formulae as alternative to oral administration and studies of release in vitro were carried out showing that the selected excipients do not pose an obstacle to the cession of methimzole, even though the PLO samples were made more slowly.
Abstract: Our objective has been the development and study of the stability of transdermal methimazole formulae as alternative to oral administration. Preparation of F-127 and PLO Pluronic gel (Pluronic lecitin organogel) are described, as well as their characteristics from transmission electron microscopy. The possible structural and rheological changes to both transdermal forms were studied in terms of composition, temperature and time. The trial period was from 24 hr to 3 months after preparation. Furthermore, identical tests were carried out on formulae conserved for 1 year after production to check their integrity. Studies of release in vitro were carried out showing that the selected excipients do not pose an obstacle to the cession of methimazole, even though the PLO samples were made more slowly.