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1.
A gastro retentive floating drug delivery system with multiple-unit minitab’s based on gas formation technique was developed
in order to prolong the gastric residence time and to increase the overall bioavailability of the drug. The system consists
of the drug-containing core units prepared by direct compression process, which are coated with three successive layers of
an inner seal coat, effervescent layer (sodium bicarbonate) and an outer gas-entrapped polymeric membrane of an polymethacrylates
(Eudragit RL30D, RS30D, and combinations of them). Only the system using Eudragit RL30D and combination of them as a gas-entrapped
polymeric membrane could float. The time to float decreased as amount of the effervescent agent increased and coating level
of gas-entrapped polymeric membrane decreased. The optimum system floated completely within 3 min and maintained the buoyancy
over a period of 12 h. The drug release was controlled and linear with the square root of time. Increasing coating level of
gas-entrapped polymeric membrane decreased the drug release. Both the rapid floating and the controlled release properties
were achieved in the multiple-unit floating drug delivery system developed in this present study. The analysis of the parameter
dissolution data after storage at 40 °C and 75% RH for 3 months showed, no significant change indicating the two dissolution
profiles were considered to be similar (f2 value is more than 50). 相似文献
2.
The present work investigates the feasibility of the design of a novel floating elementary osmotic pump tablet (FEOPT) to
prolong the gastric residence of a highly water-soluble drug. Diethylcarbamazine citrate (DEC) was chosen as a model drug.
The FEOPT consisted of an osmotic core (DEC, mannitol, and hydrophilic polymers) coated with a semipermeable layer (cellulose
acetate) and a gas-generating gelling layer (sodium bicarbonate, hydrophilic polymers) followed by a polymeric film (Eudragit
RL 30D). The effect of formulation variables such as concentration of polymers, types of diluent, and coat thickness of semipermeable
membrane was evaluated in terms of physical parameters, floating lag time, duration of floatation, and in vitro drug release. The Fourier transform infrared and X-ray diffraction analysis were carried out to study the physicochemical
changes in the drug excipients powder blend. The integrity of the orifice and polymeric film layer was confirmed from scanning
electron microscopy image. All the developed FEOPT showed floating lag time of less than 8 min and floating duration of 24 h.
A zero-order drug release could be attained for DEC. The formulations were found to be stable up to 3 months of stability
testing at 40°C/75% relative humidity. 相似文献
3.
Mutalik S Manoj K Reddy MS Kushtagi P Usha AN Anju P Ranjith AK Udupa N 《AAPS PharmSciTech》2008,9(2):651-659
The purpose of this study was to develop a once daily sustained release tablet of aceclofenac using chitosan and an enteric
coating polymer (hydroxypropyl methylcellulose phthalate or cellulose acetate phthalate). Overall sustained release for 24 h
was achieved by preparing a double-layer tablet in which the immediate release layer was formulated for a prompt release of
the drug and the sustained release layer was designed to achieve a prolonged release of drug. The preformulation studies like
IR spectroscopic and differential scanning calorimetry showed the absence of drug–excipient interactions. The tablets were
found within the permissible limits for various physicochemical parameters. Scanning electron microscopy was used to visualize
the surface morphology of the tablets and to confirm drug release mechanisms. Good equivalence in the drug release profile
was observed when drug release pattern of the tablet containing chitosan and hydroxypropyl methylcellulose phthalate (M-7)
was compared with that of marketed tablet. The optimized tablets were stable at accelerated storage conditions for 6 months
with respect to drug content and physical appearance. The results of pharmacokinetic studies in human volunteers showed that
the optimized tablet (M-7) exhibited no difference in the in vivo drug release in comparison with marketed tablet. No significant difference between the values of pharmacokinetic parameters
of M-7 and marketed tablets was observed (p > 0.05; 95% confidence intervals). However the clinical studies in large scale and, long term and extensive stability studies
at different conditions are required to confirm these results. 相似文献
4.
The purpose of this study was to develop a drug-loaded nanosystem that has the ability to achieve flexible yet rate-controlled
release of model drug isoniazid (INH) employing either an aqueous or emulsion-based salting-out approach. Formulation conditions
were aimed at reducing the polymeric size with subsequent rate-modulated INH release patterns from the polymeric nanosystem.
The emulsion-based salted-out nanosystems had particle sizes ranging from 77–414 nm and a zeta potential of −24 mV. The dispersant
dielectric constant was set at 78.5 and a conductivity of 3.99 mS/cm achieved. The reduced nanosystem size of the aqueous-based
approach has demonstrated an intrinsically enhanced exposure of methacrylic acid-ethyl acrylate to zinc sulphate which was
employed as a crosslinking reagent. This resulted in robustly interconnected polymeric supports in which INH was efficiently
embedded and subsequently released. The multi-layer perceptron data obtained showed that the aqueous and emulsion-based salting
out approaches had Power (law) (MSE = 0.020) and Linear (MSE = 0.038) relationships, respectively. Drug release from the nanosystems
occurred in two phases with an initial burst-release in aqueous-based nanosystems (30–100%) and significantly lower bursts
observed in emulsion-based nanosystems (20–65%) within the first 2 h. This was followed by a gradual exponential release phase
over the remaining 12 h. The nanosystems developed demonstrated the ability to control the release of INH depending on the
formulation approach adopted. 相似文献
5.
The purpose of this research was to develop the hydrodynamically balanced delivery system of Clarithromycin (CLA) which, after
oral administration should have the ability to prolong gastric residence time with the desired in vitro release profile for the localized action in the stomach, in the treatment of Helicobacter pylori (H.pylori) mediated peptic ulcer. By applying wet granulation technique floating tablets of Clarithromycin were prepared.
The proportion of sodium bicarbonate was varied to get the least possible lag time, also the polymer part varied to get the
desired release. In vivo radiographic studies were performed with Barium sulphate loaded formulation to justify the increased gastric residence time
of the dosage form in the stomach, based on the floating principle. The formulation developed using 66.2% Clarithromycin,
12% HPMC K4M polymer, 8% sodium bicarbonate gave floating lag time less than 3 min with a floating time of 12 h, and an in vitro release profile very near to the desired release. X-ray studies showed the enhanced gastric residence time of the tablet
to 220 ± 30 min. The mechanism of release of Clarithromycin from the floating tablets is anomalous diffusion transport and
follows zero order kinetics. In vivo radiographic studies suggest that the tablet has increased gastric residence time for the effective localized action of the
antibiotic (Clarithromycin) in the treatment of H.pylori mediated peptic ulcer. 相似文献
6.
Yoshida VM de Oliveira Junior JM Gonçalves MM Vila MM Chaud MV 《AAPS PharmSciTech》2011,12(2):658-664
The aim of this study was to develop and evaluate a floating multiparticulate gastroretentive system for the modified release
of zidovudine (AZT). AZT was used as a model drug water-soluble at therapeutic doses. The floating gastroretentive system
was obtained by co-precipitation, after solvent diffusion and evaporation. The proposed system was evaluated in vitro for particle morphology, lag time and floating time, loading rate, release profile, and the release kinetic of AZT release.
AZT’s physico-chemical characteristics were evaluated by differential scanning calorimetry (DSC), X-ray diffraction (XDR)
and infrared spectroscopy (IR). The particles obtained were sphere-shaped, hollow, and had porous walls. The floating was
immediate, and floating time was higher than 12 h. The loading rate was 34.0 ± 9.0%. The system obtained had an extended release.
DSC and XDR results showed a modification in AZT’s solid state. IR spectroscopy revealed that the chemical structure of the
AZT was unchanged. The hollow microballoons presented gastroretentive, floating, and extended-release properties. 相似文献
7.
Interpolyelectrolyte (IPE) complexation between carrageenan (CG) and Eudragit E (EE) was studied in 0.1 M HCl and was used
to develop floating matrix tablets aimed to prolong gastric-residence time and sustain delivery of the loaded drug. The optimum
EE/CG IPE complexation weight ratio (0.6) was determined in 0.1 M HCl using apparent viscosity measurements. The IPE complex
was characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. Metronidazole matrix tablets
were prepared by direct compression using EE, CG, or hybrid EE/CG with ratio optimal for IPE complexation. Corresponding effervescent
tablets were prepared by including Na bicarbonate as an effervescent agent. Tablets were evaluated for in vitro buoyancy and drug release in 0.1 M HCl. Both CG and EE–CG effervescent matrices (1:2 drug to polymer weight ratio, 60 mg
Na bicarbonate) achieved fast and prolonged floating with floating lag times less than 30 s and floating duration of more
than 10 h. The corresponding EE effervescent matrices showed delayed floating and rapid drug release, and completely dissolved
after 3 h of dissolution. CG matrices showed an initial burst drug release (48.3 ± 5.0% at 1 h) followed by slow drug release
over 8 h. EE–CG matrices exhibited sustained drug release in almost zero-order manner for 10 h (68.2 ± 6.6%). The dissolution
data of these matrices were fitted to different dissolution models. It was found that drug release followed zero-order kinetics
and was controlled by the superposition of the diffusion and erosion. 相似文献
8.
Chuong MC Palugan L Su TM Busano C Lee R Di Pretoro G Shah A 《AAPS PharmSciTech》2010,11(4):1650-1661
Vitamin B3 is made up of niacin (nicotinic acid) and its amide, niacinamide. Both have equivalent vitamin activity, but only niacin
(not niacinamide) is effective in lowering elevated low-density lipoprotein cholesterol and triglyceride levels in the blood.
Administration of an extended-release (ER) oral tablet would frequently encounter food. If hydrogel is used to formulate the
matrix of a biopharmaceutical classification system I drug (high solubility and high permeability), the dosage form absorbs
water and swells.. The softened outer layer may be slashed off by food present in the stomach, thus, exposing the core tablet
more readily for water absorption and speeding up drug release from its original designed rate. This project aimed to formulate
niacin CR pellets made of hydrophobic inert matrix. After niacin was melted with excipients and cooled, the mass was extruded
and spheronized into pellets. Size distribution and flowability were determined before pellets were filled into hard gelatin
capsule. The USP dissolution study revealed that a candidate formulation of 250 mg in strength released similar amount of
niacin as its commercial reference, niacin controlled-release 500 mg tablet, in 6 h (223.9 ± 23.8 mg, n = 4 versus 259.4 ± 2.6 mg, n = 3). The differential scanning calorimetry study of the pellets in capsules stored in 40°C for 4 weeks, and the content
assay of capsules in 40°C up to 6 months suggested that niacin was stable within the innovative formulation. In vitro release from this innovative ER capsules stored at 40°C up to 4 weeks were also investigated. 相似文献
9.
A novel gastro retentive controlled release drug delivery system of verapamil HCl was formulated in an effort to increase
the gastric retention time of the dosage form and to control drug release. Hydroxypropylmethylcellulose (HPMC), carbopol,
and xanthan gum were incorporated for gel-forming properties. Buoyancy was achieved by adding an effervescent mixture of sodium
bicarbonate and anhydrous citric acid. In vitro drug release studies were performed, and drug release kinetics was evaluated using the linear regression method. The optimized
intragastric floating tablet composed of 3:2 of HPMC K4M to xanthan gum exhibited 95.39% drug release in 24 h in vitro, while the buoyancy lag time was 36.2 s, and the intragastric floating tablet remained buoyant for >24 h. Zero-order and
non-Fickian release transport was confirmed as the drug release mechanism from the optimized formulation (F7). X-ray studies
showed that total buoyancy time was able to delay the gastric emptying of verapamil HCl intragastric floating tablet in mongrel
dogs for more than 4 h. Optimized intragastric floating tablet showed no significant change in physical appearance, drug content,
total buoyancy time, or in vitro dissolution pattern after storage at 40°C/75% relative humidity for 3 months. 相似文献
10.
The objective of the present study was to develop once-daily sustained-release matrix tablets of nicorandil, a novel potassium
channel opener used in cardiovascular diseases. The tablets were prepared by the wet granulation method. Ethanolic solutions
of ethylcellulose (EC), Eudragit RL-100, Eudragit RS-100, and polyvinylpyrrolidone were used as granulating agents along with
hydrophilic matrix materials like hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose, and sodium alginate.
The granules were evaluated for angle of repose, bulk density, compressibility index, total porosity, and drug content. The
tablets were subjected to thickness, diameter, weight variation test, drug content, hardness, friability, and in vitro release
studies. The granules showed satisfactory flow properties, compressibility, and drug content. All the tablet formulations
showed acceptable pharmacotechnical properties and complied with in-house specifications for tested parameters. According
to the theoretical release profile calculation, a oncedaily sustained-release formulation should release 5.92 mg of nicorandil
in 1 hour, like conventional tablets, and 3.21 mg per hour up to 24 hours. The results of dissolution studies indicated that
formulation F-I (drug-to-HPMC, 1∶4; ethanol as granulating agent) could extend the drug release up to 24 hours. In the further
formulation development process, F-IX (drug-to-HPMC, 1∶4; EC 4% wt/vol as granulating agent), the most successful formulation
of the study, exhibited satisfactory drug release in the initial hours, and the total release pattern was very close to the
theoretical release profile. All the formulations (except F-IX) exhibited diffusion-dominated drug release. The mechanism
of drug release from F-IX was diffusion coupled with erosion. 相似文献
11.
The purpose of this work was to develop and optimize gliclazide-loaded alginate–methyl cellulose mucoadhesive microcapsules
by ionotropic gelation using central composite design. The effect of formulation parameters like polymer blend ratio and cross-linker
(CaCl2) concentration on properties of gliclazide-loaded alginate–methyl cellulose microcapsules like drug encapsulation efficiency
and drug release were optimized. The optimized microcapsules were subjected to swelling, mucoadhesive, and in vivo studies. The observed responses coincided well with the predicted values from the optimization technique. The optimized microcapsules
showed high drug encapsulation efficiency (83.57 ± 2.59% to 85.52 ± 3.07%) with low T
50% (time for 50% drug release, 5.68 ± 0.09 to 5.83 ± 0.11 h). The in vitro drug release pattern from optimized microcapsules was found to be controlled-release pattern (zero order) with case II transport
release mechanism. Particle sizes of these optimized microcapsules were 0.767 ± 0.085 to 0.937 ± 0.086 mm. These microcapsules
also exhibited good mucoadhesive properties. The in vivo studies on alloxan-induced diabetic rats indicated the significant hypoglycemic effect that was observed 12 h after oral
administration of optimized mucoadhesive microcapsules. The developed and optimized alginate–methyl cellulose microcapsules
are suitable for prolonged systemic absorption of gliclazide to maintain lower blood glucose level and improved patient compliance. 相似文献
12.
Summary and Conclusions Decreasing the dose frequency of cefpodoxime proxetil increases patient compliance; patients prefer to take the drug once
daily. It also improves the rate of bacterial killing and hastens the cure from the indications, and therefore increases compliance.
The hydrophilic matrix of HPMC controlled the cefpodoxime proxetil release effectively for 24 hours; hence, the formulation
can be considered as a once-daily sustained-release tablet of cefpodoxime proxetil. The formulation showed acceptable pharmacotechnical
properties and assay requirements. In vitro dissolution studies indicated a sustained-release pattern throughout 24 hours
of the study that was comparable to the theoretical release profile. Drug release kinetics indicated that drug release was
best explained by Higuchi’s equation, as these plots showed the highest linearity (r
2=0.9734), but a close relationship was also noted with zero-order kinetics (r
2=0.9708). Korsmeyer’s plots indicated ann value of 0.57, which was indicative of an anomalous diffusion mechanism or diffusion coupled with erosion; hence, the drug
release was controlled by more than one process. Hixson-Crowell plots indicated a change in surface area and diameter of the
tablets with the progressive dissolution of the matrix as a function of time.
Published: September 22, 2006 相似文献
13.
The release kinetics of four model aroma compounds from coarse (d
32 = 1.0 μm) and fine (d
32 = 0.25 μm) eicosane and hydrogenated palm stearin (HPS) emulsions prepared with either solid or liquid lipid droplets were
measured using a model mouth instrument. For both lipids, the release of aroma compounds from emulsions with solid droplets
was higher than from emulsions with liquid droplets. This difference was greater for less polar aroma compounds. The release
from solid eicosane droplets increased with particle size but no such effect was observed for HPS emulsions, however, the
release from solid eicosane was higher than solid HPS. The initial aroma release profile of the solid droplet emulsion matches
that of a similar liquid oil emulsion but requires much less added aroma.
Meeting presentation: Presented at 98th AOCS Annual Meeting and Expo in Quebec City, Canada. 相似文献
14.
Diego A. Chiappetta Ángel M. Carcaboso Carlos Bregni Modesto Rubio Guillermo Bramuglia Alejandro Sosnik 《AAPS PharmSciTech》2009,10(1):1-6
The aim of this work was to develop indinavir pediatric anti-HIV/AIDS formulations enabling convenient dose adjustment, ease
of oral administration, and improved organoleptic properties by means of the generation of drug-loaded microparticles made
of a polymer that is insoluble under intake conditions and dissolves fast in the stomach in order to completely release the
active agent. Indinavir-loaded microparticles made of a pH-dependent polymeric excipient soluble at pH < 5, Eudragit E100,
were prepared using a double emulsion solvent diffusion technique and the in vitro release profiles characterized. Finally, taste masking properties were evaluated in blind randomized sensory experiments
by ten healthy human volunteers. The use of a w/o/o emulsion system resulted in indinavir loads around 90%. Thermal analysis
of the microparticles by differential scanning calorimetry revealed that indinavir appeared mainly dispersed at the molecular
level. Concentrations of residual organic solvents as determined by gas chromatography were below the upper limits specified
by the European Pharmacopeia for pharmaceutical oral formulations. Then, the behavior of drug-containing microparticles in
aqueous media at different pH values was assessed. While they selectively dissolved in gastric-like medium, in tap water (intake
conditions), the matrix remained almost unchanged and efficiently prevented drug dissolution. Finally, sensoring taste tests
performed by volunteers indicated that systems with indinavir loads ∼15% displayed acceptable taste. This work explored the
production of indinavir-containing microparticles based on a common pharmaceutical excipient as a means for the improvement
of medicines of drugs involved in the treatment of HIV/AIDS. For systems containing about 15% drug, taste studies confirmed
the acceptability of the formulation. In pediatric regimes, this composition would require an acceptable amount of formulation
(0.7–1.5 g).
Diego A. Chiappetta and ángel M. Carcaboso contributed equally to this work. 相似文献
15.
Siahi-Shadbad MR Asare-Addo K Azizian K Hassanzadeh D Nokhodchi A 《AAPS PharmSciTech》2011,12(4):1176-1182
The objective of this study was to investigate the release behaviour of propranolol hydrochloride from psyllium matrices in
the presence hydrophilic polymers. The dissolution test was carried out at pH 1.2 and pH 6.8. Binary mixtures of psyllium
and hydroxypropyl methylcellulose (HPMC) used showed that an increase in the percentage of HPMC in the binary mixtures caused
a significant decrease in the release rate of propranolol. Psyllium–alginate matrices produced lower drug release as compared
to when the alginate was the matrix former alone. When sodium carboxy methyl cellulose (NaCMC) was incorporated into the psyllium,
the results showed that matrices containing the ratio of psyllium–NaCMC in the 1:1 ratio are able to slow down the drug release
significantly as compared to matrices made from only psyllium or NaCMC as retardant agent suggesting that there could be a
synergistic effect between psyllium and NaCMC. The double-layered tablets showed that the psyllium and HPMC in the outer shell
of an inner formulation of psyllium alone had the greatest effect of protecting the inner core and thus producing the lowest
drug release (DE = 38%, MDT = 93 min). A significant decrease in the value of n in Q = kt
n
from 0.70 to 0.51 as the psyllium content was increased from 50 to 150 mg suggests that the presence of psyllium in HPMC
matrices affected the release mechanism. Psyllium powder had the ability in the combination with other hydrophilic polymers
to produce controlled release profiles. Care and consideration should as such be taken when formulating hydrophilic matrices
in different combinations. 相似文献
16.
The objectives of this study were to develop and evaluate a novel self-emulsifying floating drug delivery system (SEFDDS)
that resulted in improved solubility, dissolution, and controlled release of the poorly water-soluble tetrahydrocurcumin (THC).
The formulations of liquid self-emulsifying drug delivery system (SEDDS; mixtures of Labrasol, Cremophor EL, Capryol 90, Labrafac
PG) were optimized by solubility assay and pseudo-ternary phase diagram analysis. The liquid SEDDS was mixed with adsorbent
(silicon dioxide), glyceryl behenate, pregelatinized starch, sodium starch glycolate, and microcrystalline cellulose and transformed
into pellets by the extrusion/spheronization technique. The resulting pellets with 22% liquid SEDDS had a uniform size and
good self-emulsification property. The microemulsions in aqueous media of different self-emulsifying floating pellet formulations
were in a particle size range of 25.9–32.5 nm. Use of different weight proportions of glyceryl behenate and sodium starch
glycolate in pellet formulations had different effects on the floating abilities and in vitro drug release. The optimum formulation (F2) had a floating efficiency of 93% at 6 h and provided a controlled release of THC
over an 8-h period. The release rate and extent of release of THC liquid SEDDS (80% within 2 h) and self-emulsifying floating
pellet formulation (80% within 8 h) were significantly higher than that of unformulated THC (only 30% within 8 h). The pellet
formulation was stable under intermediate and accelerated storage conditions for up to 6 months. Controlled release from this
novel SEFDDS can be a useful alternative for the strategic development of oral solid lipid-based formulations. 相似文献
17.
The objective of the present research was to investigate the feasibility of using non-ionic surfactant vesicles (niosomes)
as carriers for the ophthalmic controlled delivery of a water soluble local antibiotic; gentamicin sulphate. Niosomal formulations
were prepared using various surfactants (Tween 60, Tween 80 or Brij 35), in the presence of cholesterol and a negative charge
inducer dicetyl phosphate (DCP) in different molar ratios and by employing a thin film hydration technique. The ability of
these vesicles to entrap the studied drug was evaluated by determining the entrapment efficiency %EE after centrifugation
and separation of the formed vesicles. Photomicroscopy and transmission electron microscopy as well as particle size analysis
were used to study the formation, morphology and size of the drug loaded niosomes. Results showed a substantial change in
the release rate and an alteration in the %EE of gentamicin sulphate from niosomal formulations upon varying type of surfactant,
cholesterol content and presence or absence of DCP. In-vitro drug release results confirmed that niosomal formulations have exhibited a high retention of gentamicin sulphate inside the
vesicles such that their in vitro release was slower compared to the drug solution. A preparation with 1:1:0.1 molar ratio of Tween 60, cholesterol and DCP
gave the most advantageous entrapment (92.02% ± 1.43) and release results (Q8h = 66.29% ± 1.33) as compared to other compositions. Ocular irritancy test performed on albino rabbits, showed no sign of
irritation for all tested niosomal formulations. 相似文献
18.
Valence M. K. Ndesendo Viness Pillay Yahya E. Choonara Lisa C. du Toit Eckhart Buchmann Leith C. R. Meyer Riaz A. Khan Uwe Rosin 《AAPS PharmSciTech》2010,11(2):793-808
The purpose of this study was to develop and evaluate the bioadhesivity, in vitro drug release, and permeation of an intravaginal bioadhesive polymeric device (IBPD) loaded with 3′-azido-3′-deoxythymidine
(AZT) and polystyrene sulfonate (PSS). Modified polyamide 6,10, poly(lactic-coglycolic acid), polyacrylic acid, polyvinyl
alcohol, and ethylcellulose were blended with model drugs AZT and PSS as well as radio-opaque barium sulfate (BaSO4) and then
compressed into caplet devices on a tableting press. One set of devices was coated with 2% w/v pentaerythritol polyacrylic acid (APE-PAA) while another remained uncoated. Thermal analysis was performed on the constituent
polymers as well the IBPD. The changes in micro-environmental pH within the simulated human vaginal fluid due to the presence
of the IBPD were assessed over a period of 30 days. Textural profile analysis indicated that the bioadhesivity of the APE-PAA-coated
devices (3.699 ± 0.464 N; 0.0098 ± 0.0004 J) was higher than that of the uncoated devices (1.198 ± 0.150 N; 0.0019 ± 0.0001 J).
In addition, BaSO4-facilitated X-ray imaging revealed that the IBPD adhered to pig vaginal tissue over the experimental period
of 30 days. Controlled drug release kinetics was obtained over 72 days. During a 24-h permeation study, an increase in drug
flux for both AZT (0.84 mg cm−2 h−1) and PSS (0.72 mg cm−2 h−1) was realized up to 12 h and thereafter a steady-state was achieved. The diffusion and dissolution dynamics were mechanistically
deduced based on a chemometric and molecular structure modeling approach. Overall, results suggested that the IBPD may be
sufficiently bioadhesive with desirable physicochemical and physicomechanical stability for use as a prolonged intravaginal
drug delivery device. 相似文献
19.
The present investigation was aimed at developing cytarabine-loaded poly(lactide-coglycolide) (PLGA)-based biodegradable nanoparticles
by a modified nanoprecipitation which would have sustained release of the drug. Nine batches were prepared as per 32 factorial design to optimize volume of the co-solvent (0.22–0.37 ml) and volume of non-solvent (1.7–3.0 ml). A second 32 factorial design was used for optimization of drug: polymer ratio (1:5) and stirring time (30 min) based on the two responses,
mean particle size (125 ± 2.5 nm), and percentage entrapment efficiency (21.8 ± 2.0%) of the Cyt-PLGA nanoparticles. Optimized
formulation showed a zeta potential of −29.7 mV indicating good stability; 50% w/w of sucrose in Cyt-PLGA NP was added successfully as cryoprotectant during lyophilization for freeze-dried NPs and showed
good dispersibility with minimum increase in their mean particle sizes. The DSC thermograms concluded that in the prepared
PLGA NP, the drug was present in the amorphous phase and may have been homogeneously dispersed in the PLGA matrix. In vitro drug release from the pure drug was complete within 2 h, but was sustained up to 24 h from PLGA nanoparticles with Fickian
diffusion. Stability studies showed that the developed PLGA NPs should be stored in the freeze-dried state at 2–8°C where
they would remain stable in terms of both mean particle size and drug content for 2 months. 相似文献
20.
Muhammad Harris Shoaib Saniah Al Sabah Siddiqi Rabia Ismail Yousuf Kamran Zaheer Muhammad Hanif Saeed Rehana Sabahat Jabeen 《AAPS PharmSciTech》2010,11(2):708-718
The objective of the present study was to develop a once-daily sustained-release (SR) matrix tablet of famotidine. Nine different
formulations (F1–F9) were prepared by direct compression method using Avicel PH101 as filler/binder in the range of 41–27%
in F1–F3, 18–22% in F4–F7, and 16–18% in F8–F9 and hydroxypropyl methylcellulose (4,000 cps) as hydrophilic matrix was used
in F1–F3 from 19% to 30%, around 40% in F4–F7, and 42–45% in F8–F9. Talc and Aerosil were added in the ratio of 0.7–1.2%.
The tablets were subjected to various physical parameters including weight variation test, hardness, thickness, diameter,
friability, and in vitro release studies. Assay was also performed according to the USP 30 NF 25 procedure. The results of the physical parameters
and assay were found to be within the acceptable range. In vitro dissolution results indicated that formulation F4–F7, having around 40% of rate control polymer, produced a SR pattern throughout
24 h. F1–F3 showed drug release at a faster rate, while F8–F9 released much slower, i.e., <80% in 24 h. Model-dependent and
model-independent methods were used for data analysis and the best results were observed for F4 in zero order (r
2 = 0.984) and F6 in Korsmeyer and Higuchi (r
2 = 0.992 and 0.988). The parameter n indicated anomalous diffusion, while β in Weibull showed a parabolic curve with higher initial slope. The f
2 similarity test was performed taking F4 as a reference formulation. Only the F5–F7 formulations were similar to the reference
formulation F4. The mean dissolution time was around 10 h for the successful formulation. 相似文献