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1.
Compaction of controlled-release coated pellets into tablets is challenging because of the fusion of pellets and the rupturing
of coated film. The difficulty in compaction intensifies with the use of extremely water-soluble drugs. Therefore, the present
study was conducted to prepare and compact pellets containing pseudoephedrine hydrochloride as an extremely water-soluble
model drug. The pellets were produced using an extrusion–spheronization technique. The drug-loaded pellets were coated to
extend the drug release up to 12-h employing various polymers, and then they were compressed into tablets using microcrystalline
cellulose Ceolus KG-801 as a novel tabletting excipient. The in vitro drug release studies of coated pellets and tablets were undertaken using the USP basket method in dissolution test apparatus
I. The amount of drug released was analyzed at a wavelength of 215 nm. The combined coatings of hydroxypropyl methylcellulose
and Kollicoat SR-30D yielded 12-h extended-release pellets with drug release independent of pH of dissolution medium following
zero-order kinetics. The drug release from the tablets prepared using inert Celous KG-801 granules as tabletting excipient
was found faster than that of coated pellets. However, a modification in drug release rate occurred with the incorporation
of inert Ceolus KG-801 pellets. The drug dissolution profile from tablets containing 40% w/w each of coated pellets and inert
granules along with 20% w/w inert pellets was found to be closely similar to that of coated pellets. Furthermore, the friability,
tensile strength, and disintegration time of the tablets were within the USP specifications. 相似文献
2.
Vaishali A. Kilor Nidhi P. Sapkal Jasmine G. Awari Bharti D. Shewale 《AAPS PharmSciTech》2010,11(1):336-343
In the present study, an attempt was made to prepare immediate-release enteric-coated pellets of aceclofenac, a poorly soluble
nonsteroidal anti-inflammatory drug that has a gastrointestinal intolerance as its serious side effect. Formulation of enteric-coated
pellets with improved solubility of aceclofenac could address both of these problems. To achieve these goals, pellets were
prepared by extrusion–spheronization method using pelletizing agents that can contribute to the faster disintegration and
thereby improve the solubility of the drug. Different disintegrants like β-cyclodextrin, kollidon CL, Ac-Di-Sol, and sodium
starch glycolate were tried in order to further improve disintegration time. The pellets were characterized for drug content,
particle size distribution, flow properties, infrared spectroscopy, surface morphology, disintegration rate, and dissolution
profile. The formulations, which showed best disintegration and dissolution profiles, were coated with Eudragit L100-55, an
enteric-coated polymer which does not dissolve at gastric pH but dissolves at intestinal pH, releasing the drug immediately
in the dissolution medium. The optimized enteric-coated formulation containing 20% κ-carrageenan, lactose, and sodium starch
glycolate as a disintegrant did inhibit the release of the drug for 2 h in 0.1 N HCl, whereas 87% of the drug was released
within 45 min. The improvement was substantial when it was compared with solubility of pure drug under the same conditions.
Thus, dissolution profiles suggested that combination of κ-carrageenan and sodium starch glycolate resulted into fast-disintegrating,
immediate-release pellets, overcoming the bioavailability problem of the poorly soluble drug, aceclofenac, and enteric coating
of these pellets avoids the exposure of aceclofenac to ulcer-prone areas of the gastrointestinal tract. 相似文献
3.
Meka Lingam Thadisetty Ashok Vobalaboina Venkateswarlu Yamsani Madhusudan Rao 《AAPS PharmSciTech》2008,9(4):1253-1261
A biphasic gastroretentive floating drug delivery system with multiple-unit mini-tablets based on gas formation technique
was developed to maintain constant plasma level of a drug concentration within the therapeutic window. The system consists
of loading dose as uncoated core units, and prolonged-release core units are prepared by direct compression process; the latter
were coated with three successive layers, one of which is seal coat, an effervescent (sodium bicarbonate) layer, and an outer
polymeric layer of polymethacrylates. The formulations were evaluated for quality control tests, and all the parameters evaluated
were within the acceptable limits. The system using Eudragit RL30D and combination of them as polymeric layer could float
within acceptable time. The drug release was linear with the square root of time. The rapid floating and the controlled release
properties were achieved in this present study. When compared with the theoretical release profile, the similarity factor
of formulation with coating of RS:RL (1:3)–7.5%, was observed to be 74, which is well fitted into zero-order kinetics confirming
that the release from formulation is close to desired release profile. The stability samples showed no significant change
in dissolution profiles (p > 0.05). In vivo gastric residence time was examined by radiograms, and it was observed that the units remained in the stomach for about 5 h. 相似文献
4.
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
5.
The present study was undertaken to evaluate the gum exudates of Terminalia catappa Linn. (TC gum) as a release retarding excipient in oral controlled drug delivery system. The rheological properties of TC
gum were studied and different formulation techniques were used to evaluate the comparative drug release characteristics.
The viscosity was found to be dependent on concentration and pH. Temperature up to 60°C did not show significant effect on
viscosity. The rheological kinetics evaluated by power law, revealed the shear thinning behavior of the TC gum dispersion
in water. Matrix tablets of TC gum were prepared with the model drug dextromethorphan hydrobromide (DH) by direct compression,
wet granulation and solid dispersion techniques. The dissolution profiles of the matrix tablets were compared with the pure
drug containing capsules using the USP Basket apparatus with 500 ml phosphate buffer of pH 6.8 as a dissolution medium. The
drug release from the compressed tablets containing TC gum was comparatively sustained than pure drug containing capsules.
Even though all the formulation techniques showed reduction of dissolution rate, aqueous wet granulation showed the maximum
sustained release of more than 8 h. The release kinetics estimated by the power law revealed that the drug release mechanism
involved in the dextromethorphan matrix is anomalous transport as indicated by the release exponent n values. Thus the study confirmed that the TC gum might be used in the controlled drug delivery system as a release-retarding
polymer. 相似文献
6.
This study compared the release behavior of single-unit (tablets, capsules) and multiple-unit (minitablets in capsules) controlled-release
systems of furosemide. The swelling and erosion behaviors of these systems, which contained the swellable hydrophilic polymers
sodium alginate (high viscosity) and Carbopol 974P, were compared. Swelling and erosion experiments showed a high degree of
swelling and limited erosion for the Carbopol preparations, whereas less swelling but greater erosion was observed for the
sodium alginate preparations. The sodium alginate preparations were eroded in 6 hours, while Carbopol preparations exhibited
limited erosion within this period of time. These results appear to be attributed to the physicochemical characteristics of
the polymers used in this study. Polymer characteristics greatly influenced the release of furosemide (model drug) from the
formulations prepared and tested. Sodium alginate had a less pronounced sustained release effect compared with Carbopol (ie,
in 8 hours all 3 sodium alginate dosage forms displayed complete release of furosemide, while only 30% of the drug was released
from Carbopol dosage forms). Finally, all 3 Carbopol dosage forms (single- and multiple-unit) displayed similar release behavior
while sodium alginate dosage forms displayed a different and more distinctive behavior. Minitablets and tablets showed a greater
sustained release effect compared with capsules. Evaluation of the release data indicates that the release mechanism for sodium
alginate formulations may be attributed to erosion/dissolution, while for Carbopol it may be attributed mainly to polymer
relaxation and diffusion of the drug from the polymer surface. 相似文献
7.
The objective of present investigation was to develop venlafaxine hydrochloride-layered tablets for obtaining sustained drug
release. The tablets containing venlafaxine hydrochloride 150 mg were prepared by wet granulation technique using xanthan
gum in the middle layer and barrier layers. The granules and tablets were characterized. The in vitro drug dissolution study was conducted in distilled water. The tablets containing two lower strengths were also developed using
the same percentage composition of the middle layer. Kinetics of drug release was studied. The optimized batches were tested
for water uptake study. Radar diagrams are provided to compare the performance of formulated tablets with the reference products,
Effexor XR capsules. The granules ready for compression exhibited good flow and compressibility when xanthan gum was used
in the intragranular and extragranular fractions. Monolayer tablets failed to give the release pattern similar to that of
the reference product. The drug release was best explained by Weibull model. A unified Weibull equation was evolved to express
drug release from the formulated tablets. Lactose facilitated drug release from barrier layers. Substantial water uptake and
gelling of xanthan gum appears to be responsible for sustained drug release. The present study underlines the importance of
formulation factors in achieving same drug release pattern from three strengths of venlafaxine hydrochloride tablets. 相似文献
8.
Nicole Jedinger Simone Schrank Johannes M. Fischer Karlheinz Breinhälter Johannes Khinast Eva Roblegg 《AAPS PharmSciTech》2016,17(1):68-77
This study focused on the development of flexible (i.e., deformable) multiple-unit pellets that feature (i) a prolonged drug release, (ii) drug abuse deterrence, and (iii) a minimal risk of alcohol-induced dose dumping (ADD). Deformable pellets were prepared via an advanced continuous one-step hot-melt extrusion (HME) technique, with the drug (i.e., antipyrine and codeine phosphate) fed as an aqueous solution into the molten matrix material (i.e., cornstarch, gum arabic, and xanthan). Formulations that had suitable mechanical characteristics (i.e., high compression strength) were coated with a flexible Aquacoat® ARC film to ensure prolonged release and to avoid ADD. The pellets were characterized in terms of their mechanical properties and in vitro drug release behavior in alcoholic media. All formulations were abuse deterrent: they had a high compression strength and grinding the pellets into powder was impossible. Since the pellets comprising gum arabic and xanthan as a matrix did not remain intact during dissolution testing, they had a very fast drug release rate. Cornstarch-based pellets that swelled but remained intact in the dissolution media had a slower drug release. Coated cornstarch-based pellets had a prolonged release over 8 h and resistance to dose dumping in 20 and 40% ethanol. Our results indicate that cornstarch-based pellets manufactured via the advanced HME process followed by coating are a promising formulation that makes tampering difficult due to a high compression strength combined with robustness in alcoholic media. 相似文献
9.
Sirpa Vuorinen Jyrki Heinämäki Osmo Antikainen Mohammed Lahcini Timo Repo Jouko Yliruusi 《AAPS PharmSciTech》2009,10(2):566-573
Sugar end-capped poly-d,l-lactide (SPDLA) polymers were investigated as a potential release controlling excipient in oral sustained release matrix
tablets. The SPDLA polymers were obtained by a catalytic ring-opening polymerization technique using methyl α-d-gluco-pyranoside as a multifunctional initiator in the polymerization. Polymers of different molecular weights were synthesized
by varying molar ratios of monomer/catalyst. The matrix tablets were prepared by direct compression technique from the binary
mixtures of SPDLA and microcrystalline cellulose, and theophylline was used as a model drug. The tablet matrices showed in vitro reproducible drug release profiles with a zero-order or diffusion-based kinetic depending on the SPDLA polymer grade used.
Further release from the tablet matrices was dependent on the molecular weight of the SPDLA polymer applied. The drug release
was the fastest with the lowest molecular weight SPDLA grade, and the drug release followed zero-order rate. With the higher
molecular weight SPDLAs, more prolonged dissolution profiles for the matrix tablets (up to 8–10 h) were obtained. Furthermore,
the prolonged drug release was independent of the pH of the dissolution media. In conclusion, SPDLAs are a novel type of drug
carrier polymers applicable in oral controlled drug delivery systems. 相似文献
10.
The major aims of the present study were (1) to select a multiple-unit formulation that matched the in vitro dissolution profile
of single-unit sustained-release commercial capsules, (2) to compare the sustaining/controlling efficacy of the selected multiple-unit
formulation with that of the single-unit commercial conventional tablet and sustained-release capsules, and (3) to determine
whether an in vitro-in vivo correlation exists for single- and multiple-unit formulations. Ibuprofen (20%–60% wt/wt)-loaded
multiple-unit polystyrene microparticles were prepared by an emulsion-solvent evaporation method from an aqueous system. The
in vitro release profiles obtained in phosphate buffer of pH 6.8 for drug-loaded polystyrene microparticles and for commercial
sustained-release capsules (Fenlong-SR, 400 mg) were compared. Since the microparticles with 30% ibuprofen load showed a release
profile comparable to that of the Fenlong-SR release profile, the microparticles with this drug load were considered to be
the optimized/selected formulation and, therefore, were subjected to stability study and in vivo study in human volunteers.
A single-dose oral bioavailability study revealed significant differences in Cmax, Tmax, t1/2a, t1/2e, Ka, Ke, and AUC between the conventional tablet and optimized or Fenlong-SR capsule dosage forms. However, all the parameters, with
the exception of Ka along with relative bioavailability (F) and retard quotient (RΔ), obtained from the optimized ibuprofenloaded microparticles were lower than that obtained from the commercial Fenlong-SR
formulation. Furthermore, linear relationship obtained between the percentages dissolved and absorbed suggests a means to
predict in vivo absorption by measuring in vitro dissolution.
Published: September 1, 2006 相似文献
11.
The effect of concentration of hydrophilic (hydroxypropyl methylcellulose [HPMC]) and hydrophobic polymers (hydrogenated castor
oil [HCO], ethylcellulose) on the release rate of tramadol was studied. Hydrophilic matrix tablets were prepared by wet granulation
technique, while hydrophobic (wax) matrix tablets were prepared by melt granulation technique and in vitro dissolution studies
were performed using United States Pharmacopeia (USP) apparatus type II. Hydrophobic matrix tablets resulted in sustained
in vitro drug release (>20 hours) as compared with hydrophilic matrix tablets (<14 hours). The presence of ethylcellulose
in either of the matrix systems prolonged the release rate of the drug. Tablets prepared by combination of hydrophilic and
hydrophobic polymers failed to prolong the drug release beyond 12 hours. The effect of ethylcellulose coating (Surelease)
and the presence of lactose and HPMC in the coating composition on the drug release was also investigated. Hydrophobic matrix
tablets prepared using HCO were found to be best suited for modulating the delivery of the highly water-soluble drug, tramadol
hydrochloride. 相似文献
12.
The objective of the study was to develop guar gum matrix tablets for oral controlled release of water-soluble diltiazem hydrochloride.
Matrix tablets of diltiazem hydrochloride, using various viscosity grades of guar gum in 2 proportions, were prepared by wet
granulation method and subjected to in vitro drug release studies. Diltiazem hydrochloride matrix tablets containing either
30% wt/wt lowviscosity (LM1), 40% wt/wt medium-viscosity (MM2), or 50% wt/wt high-viscosity (HM2) guar gum showed controlled
release. The drug release from all guar gum matrix tablets followed first-order kinetics via Fickian-diffusion. Further, the
results of in vitro drug release studies in simulated gastrointestinal and colonic fluids showed that HM2 tablets provided
controlled release comparable with marketed sustained release diltiazem hydrochloride tablets (D-SR tablets). Guar gum matrix
tablets HM2 showed no change in physical appearance, drug content, or in dissolution pattern after storage at 40°C/relative
humidity 75% for 6 months. When subjectd to in vivo pharmacokinetic evaluation in healthy volunteers, the HM2 tablets provided
a slow and prolonged drug release when compared with D-SR tablets. Based on the results of in vitro and in vivo studies it
was concluded that that guar gum matrix tablets provided oral controlled release of water-soluble diltiazem hydrochloride.
Published: June 30, 2005 相似文献
13.
Priscileila C. FerrariFagner M. Souza Leandro GiorgettiGiselle F. Oliveira Marco V. ChaudHumberto G. Ferraz Raul C. Evangelista 《Carbohydrate polymers》2012,87(4):2526-2531
The purpose of this study was to prepare and characterize coated pellets for controlled drug delivery. The influence of chitosan (CS) in pellets was evaluated by swelling, in vitro drug release and intestinal permeation assays. Pellets were coated with an enteric polymer, Kollicoat® MAE 30 DP, in a fluidized-bed apparatus and the coating formulations were based on a factorial design. Metronidazole (MT) released from coated and uncoated pellets were assessed by dissolution method using Apparatus I. Intestinal permeation was evaluated by everted intestinal sac model in rats, used to study the absorption of MT from coated pellets containing CS or not through the intestinal tissue. Although the film coating avoided drug dissolution in gastric medium, the overall drug release and intestinal permeation were dependent on the presence of CS. Thus, pellets containing CS show potential as a system for controlled drug delivery. 相似文献
14.
Xiaoyu Zhang Qi Li Mingzhu Ye Zhinan Zhao Jiayi Sun Xinggang Yang Weisan Pan 《AAPS PharmSciTech》2018,19(2):610-620
The objective of this study was to prepare time-controlled release etodolac pellets to facilitate drug administration according to the body’s biological rhythm, optimize the drug’s desired effects, and minimize adverse effects. The preparation consisted of three laminal layers from center to outside: the core, the swelling layer, and the insoluble polymer membrane. Factors influenced the core and the coating films were investigated in this study. The core pellets formulated with etodolac, lactose, and sodium carboxymethyl starch (CMS-Na) were prepared by extrusion-spheronization and then coated by a fluidized bed coater. Croscarmellose sodium (CC-Na) was selected as the swelling agent, and ethyl cellulose (EC) as the controlled release layer. The prepared pellets were characterized by scanning electron microscopy and evaluated by a dissolution test and a pharmacokinetic study. Compared with commercial available capsules, pharmacokinetics studies in beagle dogs indicated that the prepared pellets release the drug within a short period of time, immediately after a predetermined lag time. A good correlation between in vitro dissolution and in vivo absorption of the pellets was exhibited in the analysis. 相似文献
15.
The purpose of the present study was to investigate the potential use of two PEGylated derivatives of rosin (PD) as sustained
release film forming materials. The derivatives differed chemically by their acid numbers—PD-1 with 120.93 and PD-2 with 88.19.
The derivative films were characterized for surface morphology, water uptake-weight loss, angle of contact, water vapor transmission
rate, mechanical properties and permeability study. Dissolution of diclofenac sodium (DS) and propranolol hydrochloride (PHL)
as model drugs was studied from coated pellets. The films of derivatives with and without plasticizers were smooth and continuous.
PD-2 films developed greater numbers of pores when in contact with phosphate buffer pH 6.8. The low weight loss, low angles
of contact and high water vapor transmission rate of PD-2 films were related to presence of higher concentration of PEG esters.
Higher tensile strength and percent elongation of PD-2 films was due to greater degree of internal plasticization of the derivative.
The permeability of films to model drugs propranolol hydrochloride and diclofenac sodium was inversely proportional to the
film thickness and dibutyl phthalate concentration in them; the permeability being greatest in PD-2 films containing 10% PEG
200. Dissolution rate of propranolol hydrochloride was higher from the coated pellets. The dissolution data followed zero
order, Baker–Lonsdale equation and Hixon–Crowell equation of release kinetics with high correlation coefficients. The mechanism
of drug release from these coated systems however followed class II transport (n > 1.0). The derivatives investigated could successfully retard release of the model drugs and offers an alternative to the
conventionally used polymers. 相似文献
16.
The aim of this study was to examine the effect of pellet size, pectin type, pectin concentration, and dissolution medium on the swelling and drug release behavior of spherical pellets containing theophylline and coated with 2 different calcium pectinates, using a multi-level factorial design approach. The spherical pellets were prepared by an extrusion-spheronization method and then coated with calcium pectinate using the diffusion-controlled interfacial complexation technique, which provides a defect-free and uniform coating on solid cores. Theophylline release from the pellets was slowed by the application of the coatings. The time to release 50% of the payload (ie, T50) in an acidic medium was approximately 7 minutes from uncoated small pellets and was 55 minutes after an amidated calcium pectinate coat was applied; a comparable coat on large pellets showed a T50 of 93 minutes. Drug release profiles of dry coated pellets showed a lag time (all less than 20 minutes) when the gel coat hydrated and swelled, followed by a zero-order release. It was found that the release rate was controlled by the pellet size, pectin type, pectin concentration, and dissolution medium. 相似文献
17.
Etodolac (ET) is a nonsteroidal anti-inflammatory drug with proved potential antitumor and uric acid lowering effects. It
shows dissolution rate-dependent bioavailability. This work was carried out to improve the dissolution rate of etodolac using
three carriers of known potential to improve solubility and hence dissolution rate of poorly soluble drugs through coevaporation
technique. The polymeric surfactant inutec, 2-hydroxypropyl-β-cyclodextrin, and tromethamine were used at three different
drug/carrier ratios. The dissolution rate of ET at pH 1.2 and 6.8 is improved in all of the solid dispersion systems compared
to that of the pure drug and physical mixtures. DSC of coevaporates at 1:5 drug/carrier ratio providing the fastest dissolution
rate suggested loss of ET crystallinity which was further confirmed by X-ray diffraction. Inutec-based coevaporate was chosen
for the formulation of ET chewable tablets. Chewable tablets (F3) that met the USP monograph specifications for ET tablets,
with 86% dissolved amount within 15 min, was chosen for in vivo absorption study in comparison with pure ET-filled hard gelatin capsules. The results showed significantly higher mean C
max and shorter mean T
max (about 2 h earlier) and about 1.32-fold higher mean AUC0–24 values for the F3 chewable tablets compared to ET-filled capsules. 相似文献
18.
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
19.
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
20.
The purpose of the research was to evaluate Sterculia foetida gum as a hydrophilic matrix polymer for controlled release preparation. For evaluation as a matrix polymer; characterization
of Sterculia foetida gum was done. Viscosity, pH, scanning electronmicrographs were determined. Different formulation aspects considered were:
gum concentration (10–40%), particle size (75–420 μm) and type of fillers and those for dissolution studies; pH, and stirring
speed were considered. Tablets prepared with Sterculia foetida gum were compared with tablets prepared with Hydroxymethylcellulose K15M. The release rate profiles were evaluated through
different kinetic equations: zero-order, first-order, Higuchi, Hixon-Crowell and Korsemeyer and Peppas models. The scanning
electronmicrographs showed that the gum particles were somewhat triangular. The viscosity of 1% solution was found to be 950
centipoise and pH was in range of 4–5. Suitable matrix release profile could be obtained at 40% gum concentration. Higher
sustained release profiles were obtained for Sterculia foetida gum particles in size range of 76–125 μm. Notable influences were obtained for type of fillers. Significant differences were
also observed with rotational speed and dissolution media pH. The in vitro release profiles indicated that tablets prepared from Sterculia foetida gum had higher retarding capacity than tablets prepared with Hydroxymethylcellulose K15M prepared tablets. The differential
scanning calorimetry results indicated that there are no interactions of Sterculia foetida gum with diltiazem hydrochloride. It was observed that release of the drug followed through surface erosion and anomalous
diffusion. Thus, it could be concluded that Sterculia foetida gum could be used a controlled release matrix polymer. 相似文献