共查询到20条相似文献,搜索用时 31 毫秒
1.
Atul C. Badhan Rajashree C. Mashru Punit P. Shah Arti R. Thakkar Nitin B. Dobaria 《AAPS PharmSciTech》2009,10(2):459-467
In the present work, sustained release gastroretentive minimatrices of amoxicillin have been designed and optimized using
central composite design. Effect of amount of xanthan gum, rate controlling polymers (HPMC K100M CR/PEO coagulant (1:1)),
carbopol 974P, and gas generating couple (sodium bicarbonate/citric acid (3:1)) was studied on dependent (response) variables,
i.e., buoyancy lag time, drug release at 1 h, time required for 95% drug release, swelling index, and bioadhesive strength.
Minimatrices were prepared by non aqueous granulation method using solution of PVP K30 in isopropyl alcohol. All the formulations
were found to contain 99.2% to 100.9% of amoxicillin per minimatrix. Optimum formulation (Formulation number AGT09) containing
high level of the independent variables was having buoyancy lag time of 7 min and drug release at 1 h was 32.5%. It required
9.39 h for 95% drug release while swelling index and bioadhesive strength were 341 and 17.9 dyn/cm2, respectively. This formulation was said to be optimum because it has minimum buoyancy lag time, requires maximum time for
95% drug release, and has higher bioadhesive capabilities. In vitro results of an optimized formulation indicate its sustained drug release and gastric retention capability, which may be very
useful for effective treatment of H. pylori infection. 相似文献
2.
Gazzi Shanker Chegonda K. Kumar Chandra Sekhara Rao Gonugunta B. Vijaya Kumar Prabhakar Reddy Veerareddy 《AAPS PharmSciTech》2009,10(2):530-539
The study aim was concerned with formulation and evaluation of bioadhesive buccal drug delivery of tizanidine hydrochloride
tablets, which is extensively metabolized by liver. The tablets were prepared by direct compression using bioadhesive polymers
such as hydroxylpropyl methylcellulose K4M, sodium carboxymethyl cellulose alone, and a combination of these two polymers.
In order to improve the permeation of drug, different permeation enhancers like beta-cyclodextrin (β-CD), hydroxylpropyl beta-cyclodextrin
(HP-β-CD), and sodium deoxycholate (SDC) were added to the formulations. The β-CD and HP-β-CD were taken in 1:1 molar ratio
to drug in formulations. Bioadhesion strength, ex vivo residence time, swelling, and in vitro dissolution studies and ex vivo permeation studies were performed. In vitro release of optimized bioadhesive buccal tablet was found to be non-Fickian. SDC was taken in 1%, 2%, and 3% w/w of the total tablet weight. Stability studies in natural saliva indicated that optimized formulation has good stability in
human saliva. In vivo mucoadhesive behavior of optimized formulation was performed in five healthy male human volunteers and subjective parameters
were evaluated. 相似文献
3.
Stomach-Specific Controlled Release Gellan Beads of Acid-Soluble Drug Prepared by Ionotropic Gelation Method 总被引:1,自引:0,他引:1
The purpose of the present work was the development and evaluation of stomach-specific controlled release mucoadhesive drug
delivery system prepared by ionotropic gelation of gellan beads, containing acid-soluble drug amoxicillin trihydrate, using
32 factorial design with concentration of gellan gum and quantity of drug as variables. The study showed that beads prepared
in alkaline cross-linking medium have higher entrapment efficiency than the acidic cross-linking medium. The entrapment efficiency
was in the range of 32% to 46% w/w in acidic medium, which increased up to 60% to 90% w/w in alkaline medium. Batches with lowest, medium, and highest drug entrapment were subjected to chitosan coating to form a
polyelectrolyte complex film. As polymer concentration increases, entrapment efficiency and particle size increases. Scanning
electron microscopy revealed spherical but rough surface due to leaching of drug in acidic cross-linking solution, dense spherical
structure in alkaline cross-linking solution, and rough surface of chitosan-coated beads with minor wrinkles. The in vitro drug release up to 7 h in a controlled manner following the Peppas model (r = 0.9998). In vitro and in vivo mucoadhesivity study showed that beads have good mucoadhesivity and more than 85% beads remained adhered to stomach mucosa
of albino rat even after 7 h. In vitro growth inhibition study showed complete eradication of Helicobacter pylori. These results indicate that stomach-specific controlled release mucoadhesive system of amoxicillin gellan beads may be useful
in H. pylori treatment. 相似文献
4.
Claudia Juliano Massimo Cossu Paola Pigozzi Giovanna Rassu Paolo Giunchedi 《AAPS PharmSciTech》2008,9(4):1153-1158
The aim of this work was to investigate the suitability of some polymeric films as buccal systems for the delivery of the
antiseptic drug chlorhexidine diacetate, considered as a valid adjunct in the treatment of oral candidiasis. Six different
film formulations, mono- or double-layered, containing 5 or 10 mg of chlorhexidine diacetate, respectively, and alginate and/or
hydroxypropylmethylcellulose and/or chitosan as excipients, were prepared by a casting-solvent evaporation technique and characterized
in terms of drug content, morphology (scanning electron microscopy), drug release behavior, and swelling properties. Moreover,
the in vivo concentrations of chlorhexidine diacetate in saliva were evaluated after application of a selected formulation on the oral
mucosa of healthy volunteers. The casting-solvent evaporation proved to be a suitable technique for preparing soft, flexible,
and easily handy mono- or double-layered chlorhexidine-loaded films. Some prepared formulations showed favorable in vitro drug release rates and swelling properties. The behavior of a selected formulation, chosen on the basis of its in vitro release results, was preliminarily investigated in vivo after application in the oral cavity of healthy volunteers. The films were well tolerated and the salivary chlorhexidine
concentrations were maintained above the minimum inhibitory concentration for Candida albicans for almost 3 h. These preliminary results indicate that polymeric films can represent a valid vehicle for buccal delivery
of antifungal/antimicrobial drugs. 相似文献
5.
The aim of the present study was to develop and evaluate a buccal adhesive tablet containing ondansetron hydrochloride (OH).
Special punches and dies were fabricated and used while preparing buccal adhesive tablets. The tablets were prepared using
carbopol (CP 934), sodium alginate, sodium carboxymethylcellulose low viscosity (SCMC LV), and hydroxypropylmethylcellulose
(HPMC 15cps) as mucoadhsive polymers to impart mucoadhesion and ethyl cellulose to act as an impermeable backing layer. The
formulations were prepared by direct compression and characterized by different parameters such as weight uniformity, content
uniformity, thickness, hardness, swelling index, in vitro drug release studies, mucoadhesive strength, and ex vivo permeation study. As compared with the optimized formulation composed of OH—5 mg, CP 934—30 mg, SCMC LV—165 mg, PEG 6000—40 mg,
lactose—5 mg, magnesium stearate—1.5 mg, and aspartame—2 mg, which gave the maximum release (88.15%), non-bitter (OH) that
form namely ondansetron base and complexed ondansetron was used in order to make the selected formulation acceptable to human.
The result of the in vitro release studies and permeation studies through bovine buccal mucosa revealed that complexed ondansetron gave the maximum
release and permeation. The stability of drug in the optimized adhesive tablet was tested for 6 h in natural human saliva;
both the drug and device were found to be stable in natural human saliva. Thus, buccal adhesive tablet of ondansetron could
be an alternative route to bypass the hepatic first-pass metabolism and to improve the bioavailability of (OH). 相似文献
6.
The purpose of this study was to develop a dosage form that was easy to administer and provides rapid release of the drug
roxithromycin, using modified polysaccharides as rapidly disintegrating excipients. Modified polysaccharides co grinded treated
agar (C-TAG) and co grinded treated guar gum (C-TGG) were prepared by subjecting pure polysaccharides namely agar and guar
gum respectively to sequential processes of wetting, drying and co grinding with mannitol (1:1). The modified polysaccharides
were characterized by Scanning Electron Microscopy and Diffuse Reflectance Spectroscopy and evaluated for particle size distribution,
derived properties, swelling index and biodegradability. Optimization studies based on 22 factorial designs, with friability and disintegration time as response parameters were used to formulate orodispersible tablets
of roxithromycin and evaluated for wetting time, water absorption ratio and in vitro drug release at salivary pH 6.4 and physiological pH 7.4. Results indicated that lower levels of modified polysaccharides
namely C-TAG in F3 and C-TGG in F7 and higher levels of microcrystalline cellulose, exhibited least disintegration times without friability concerns. In vitro release of optimized formulations F3 and F7, both at salivary pH and physiological pH was found to be more than 90% within 30 min as compared to 27.82% at the same time
point of conventional formulation. Stability studies carried out as per ICH Q1A guidelines suggested the formulations to be
stable for a period of 6 months. Thus the approach of using modified polysaccharides as fast disintegrating excipient can
be used to formulate a stable orodispersible formulation. 相似文献
7.
In the present study, an attempt has been made to design controlled release colon-specific formulations of indomethacin by
employing pH responsive polymers Eudragit (L100 or S100) in matrix bases comprised of xanthan gum. The prepared tablets were
found to be of acceptable quality with low-weight variation and uniform drug content. In vitro release studies indicated rapid swelling and release of significant percentage of drug in the initial period from matrix
tablets composed of xanthan gum alone. Addition of pH responsive polymers Eudragit (L100 or S100) to xanthan gum matrix resulted
in negligible to very low drug release in the initial period in acidic to weakly acidic medium. Furthermore, with increase
in pH of the dissolution medium due to dissolution of Eudragit L100/Eudragit S100 that resulted in the formation of a porous
matrix, faster but controlled drug release pattern was observed. Thus, a sigmoidal release pattern was observed from the designed
formulations suitable for colonic delivery. Drug release mechanism in all cases was found to be of super case II type, indicating
erosion to be the primary cause of drug release. Since the drug release from almost all the matrix bases in the initial phase
was negligibly low and followed with controlled release for about 14–16 h, it was concluded that a matrix design of this composition
could have potential applications as a colon-specific drug delivery device with additional advantage of easy scale-up and
avoidance of all-or-none phenomenon associated with coated colon-specific systems. 相似文献
8.
Modified-release multiple-unit tablets of loratadine and pseudoephedrine hydrochloride with different release profiles were
prepared from the immediate-release pellets comprising the above two drugs and prolonged-release pellets containing only pseudoephedrine
hydrochloride. The immediate-release pellets containing pseudoephedrine hydrochloride alone or in combination with loratadine
were prepared using extrusion–spheronization method. The pellets of pseudoephedrine hydrochloride were coated to prolong the
drug release up to 12 h. Both immediate- and prolonged-release pellets were filled into hard gelatin capsule and also compressed
into tablets using inert tabletting granules of microcrystalline cellulose Ceolus KG-801. The in vitro drug dissolution study conducted using high-performance liquid chromatography method showed that both multiple-unit capsules
and multiple-unit tablets released loratadine completely within a time period of 2 h, whereas the immediate-release portion
of pseudoephedrine hydrochloride was liberated completely within the first 10 min of dissolution study. On the other hand,
the release of pseudoephedrine hydrochloride from the prolonged release coated pellets was prolonged up to 12 hr and followed
zero-order release kinetic. The drug dissolution profiles of multiple-unit tablets and multiple-unit capsules were found to
be closely similar, indicating that the integrity of pellets remained unaffected during the compression process. Moreover,
the friability, hardness, and disintegration time of multiple-unit tablets were found to be within BP specifications. In conclusion,
modified-release pellet-based tablet system for the delivery of loratadine and pseudoephedrine hydrochloride was successfully
developed and evaluated. 相似文献
9.
Two groups of fluconazole mucoadhesive buccal discs were prepared: (a) Fluconazole buccal discs prepared by direct compression
containing bioadhesive polymers, namely, Carbopol 974p (Cp), sodium carboxymethyl cellulose (SCMC), or sodium alginate (SALG)
in combination with hydroxypropyl methylcellulose (HPMC) or hydroxyethyl cellulose (HEC). (b) Fluconazole buccal discs prepared
by freeze drying containing different polymer combinations (SCMC/HPMC, Cp/HPMC, SALG/HPMC, and chitosan/SALG). The prepared
discs were evaluated by investigating their release pattern, swelling capacity, mucoadhesion properties, and in vitro adhesion time. In vivo evaluation of the buccal disc and in vivo residence times were also performed. Fluconazole salivary concentration after application of fluconazole buccal systems to
four healthy volunteers was determined using microbiological assay and high-performance liquid chromatography. SCMC/HPMC buccal
disc prepared by direct compression could be considered comparatively superior mucoadhesive disc regarding its in vitro adhesion time, in vivo residence time, and in vitro/in vivo release rates of the drug. Determination of the amount of drug released in saliva after application of the selected fluconazole
disc confirmed the ability of the disc to deliver the drug over a period of approximately 5 h and to reduce side effects and
possibility of drug interaction encountered during systemic therapy of fluconazole, which would be beneficial in the case
of oral candidiasis. 相似文献
10.
Yangjie Wei Michael P. Nedley Sarit B. Bhaduri Xavier Bredzinski Sai H. S. Boddu 《AAPS PharmSciTech》2015,16(2):455-465
Several attempts have been made to mask the bitter taste of oral formulations, but none have been made for injectable formulations. This study aims to mask the bitter taste of dental lidocaine HCl (LID) injection using hydroxypropyl-β-cyclodextrin (HP-β-CD) and sodium saccharin. Inclusion complexes of LID and HP-β-CD were prepared by the solution method in 1:1 and 1:2 M ratios. Inclusion complexes in solution were studied using phase solubility in phosphate buffer solutions (pH 8, 9, and 10). Freeze-dried inclusion complexes were characterized using differential scanning calorimetry (DSC), X-ray, Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and in vitro release. Injectable formulations were prepared using inclusion complexes and characterized for stability and for taste using an Alpha MOS ASTREE electronic tongue (ETongue). The association constants of HP-β-CD with lidocaine-free base and its ionized form were found to be 26.23 ± 0.00025 and 0.8694 ± 0.00045 M−1, respectively. Characterization studies confirmed the formation of stable inclusion complexes of LID and HP-β-CD. Injectable formulations were found to be stable for up to 6 months at 4°C, 25°C, and 40°C. The taste evaluation study indicated that HP-β-CD (1:1 and 1:2 M ratios) significantly improved the bitter taste of LID injectable formulation. In conclusion, inclusion complex in the 1:1 M ratio with 0.09% sodium saccharin was considered to be optimum in masking the bitter taste of LID.KEY WORDS: bitter taste, HP-β-CD, inclusion complex, injectable, lidocaine HCl, taste masking 相似文献
11.
The objective of this study was to prepare and characterize beads of Gelucire 43/01 for floating delivery of metformin hydrochloride
(MH). The beads were evaluated for particle size, surface morphology, percent drug entrapment, percent yield, differential
scanning calorimetry (DSC), in vitro floating ability, and in vitro drug release. Aging effect on storage was evaluated using hot stage microscopy (HSM), DSC, scanning electron microscopy,
and in vitro floating ability. The formed beads were sufficiently hard and spherical in shape. Photomicrographs show that the surface
was porous in nature. The average particle diameter of beads was found to be in the size range of 3.85 to 3.95 mm, and percent
entrapment was 83.07% to 86.13%. The beads demonstrated favorable in vitro floating ability. The analysis of DSC thermograms revealed no physical interaction between the lipid and the drug in the
prepared beads. Prepared formulations showed better controlled release behavior when compared with its conventional dosage
form and comparable release profile with marketed sustained release product. HSM photomicrograph showed presence of some unmelted
portion even at 43°C and completely melts on 51°C in aged sample. It was found that there was no significant effect on floating
ability of aged beads since it remains floats up to 8 h study period. Thus, it is concluded that beads of Gelucire 43/01 could
be serve as an effective carrier for highly water-soluble antihyperglycemic drugs like MH for the controlled delivery. 相似文献
12.
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
13.
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
14.
Spectrofluorimetric determination of acotiamide hydrochloride trihydrate in the presence of its oxidative degradation product 下载免费PDF全文
Khalid A. M. Attia Mohammed W. I. Nassar Ahmed El‐Olemy Sherif Ramzy 《Luminescence》2018,33(4):806-811
Acotiamide hydrochloride trihydrate is a novel gastroprokinetic drug which has been recently approved for the treatment of patients with functional dyspepsia. This study presents the first reported to investigate the fluorimetric behavior of acotiamide hydrochloride trihydrate in the presence of its oxidative degradation product. All variables that affect fluorescence intensity were studied and optimized. The described method involved the measurement of native fluorescence of the drug in ethanol at 404 nm after excitation at 326 nm. Calibration plot was found to be linear over the concentration range 0.1–0.9 μg/ml. The specificity of the method has been tested via selective determination of the studied drug in its synthetic mixtures with its degradation product. The proposed method has been successfully applied to the analysis of the drug in its new pharmaceutical dosage form and the results have been statistically compared with the reported HPLC method showing no significant differences by applying t‐test and F‐test. 相似文献
15.
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
16.
The objective of this work was to develop matrix sustained-release tablets of highly water-soluble tramadol HCl using natural
gums (xanthan [X gum] and guar [G gum]) as cost-effective, nontoxic, easily available, and suitable hydrophilic matrix systems
compared with the extensively investigated hydrophilic matrices (ie, hydroxypropyl methylcellulose [HPMC]/carboxymethyl cellulose
[CMC] with respect to in vitro drug release rate) and hydration rate of the polymers. Matrix tablets of tramadol (dose 100
mg) were produced by direct compression method. Different ratios, of 100∶0, 80∶20, 60∶40, 20∶80, 0∶100 of G gum (or X):HPMC,
X gum:G gum, and triple mixture of these polymers (G gum, X gum, HPMC) were applied. After evaluation of physical characteristics
of tablets, the dissolution test was, performed in the phosphate buffer media (pH 7.4) up to 8 hours. Tablets with only X
had the highest mean dissolution time (MDT), the least dissolution efficiency (DE8%), and released the drug following a zero-order model via swelling, diffusion, and erosion mechanisms. Guar gum alone could
not efficiently control the drug release, while X and all combinations of natural gums with HPMC could retard tramadol HCl
release. However, according to the similarity factor (f
2), pure HPMC and H8G2 were the most similar formulations to Topalgic-LP as the reference standard.
Published: March 17, 2006 相似文献
17.
AbstractThe purpose of this research was to develop cubosomal mucoadhesive in situ nasal gel to enhance the donepezil HCl delivery to the brain. Glycerol mono-oleate (GMO) and surfactant poloxamer 407 were used to prepare cubosomes. The developed formulations were characterized for particle size (PS), poly dispersity index (PDI), zeta potential (ZP), entrapment efficiency (EE), transmission electron microscopy (TEM), in vitro drug release and in vivo bio-distribution study in blood and brain tissue. Central composite design was used for the optimization purpose and the selected formulation (containing GMO 2?g and poloxamer 1.5%) was prepared in presence of gellan gum and konjac gum as gelling agent and mucoadhesive agent respectively. The optimal cubosomal dispersion and optimal cubosomal mucoadhesive in situ nasal gel were subjected to in vivo bio-distribution studies in rat model. It showed significantly higher transnasal permeation and better distribution to the brain, when compared to the drug solution. Thus, the formulated cubosomal mucoadhesive in situ gel could be considered as a promising carrier for brain targeting of CNS acting drugs through the transnasal route. 相似文献
18.
In the current study, the potential of a novel combination of a galactomannan with acarbose (100 mg) was evaluated for attaining
a desired hypoglycaemic effect over a prolonged period of time. Three major antidiabetic galactomannans viz., fenugreek gum, boswellia gum, and locust bean gum were selected in order to achieve a synergistic effect in the treatment
alongwith retardation in drug release. In vitro studies indicated that batches containing various proportions of fenugreek gum (AF40-60) were able to control drug release
for a longer duration of approximately 10–12 h. In contrast, the matrices prepared using boswellia and locust bean gum were
able to sustain the release for relatively shorter durations. Drug release mainly followed first-order release kinetics owing
to the highly soluble nature of the drug. In vivo study depicted a significant reduction (p < 0.001) in the postprandial blood glucose and triglyceride levels in the diabetic rats on treatment with formulation AF40.
Thus, the developed system provides a better control of the postprandial glycaemic levels and it also obviates the need of
conventional multiple dosing of acarbose. Furthermore, it also reduces the occurrence of side effects like diarrhea and loss
of appetite. 相似文献
19.
The aim of this paper was to evaluate the performance of different swellable polymers in the form of layered matrix tablets
to provide controlled therapeutic effect of metoprolol tartrate for twice daily administration. Seven different swellable
polymers (carrageenan, hydroxypropylmethyl cellulose, pectin, guar gum, xanthan gum, chitosan, and ethyl cellulose) were evaluated
alone or in combination as release-retardant layer. Tablets were tested for weight variation, hardness, diameter/thickness
ratio, friability, and drug content uniformity and subjected to in vitro drug-release studies. In addition, the target-release profile of metoprolol tartrate was plotted using its clinical pharmacokinetic
data, and the release profiles of the tablets were evaluated in relation to the plotted target release profile. Carrageenan
was determined as the best polymer in two-layered matrix tablet formulations due to its better accordance to the target release
profile and was selected for preparing three-layered matrix tablets. Carrageenan formulations exhibited super case II release
mechanism. Accelerated stability testing was performed on two- and three-layered matrix tablet formulations of carrageenan.
The tablets were stored at 25°C/60% relative humidity and 40°C/75% relative humidity for 6 months and examined for physical
appearance, drug content, and release characteristics. At the end of the storage time, formulations showed no change either
in physical appearance, drug content, or drug-release profile. These results demonstrated the suitability of three-layered
tablet formulation of carrageenan to provide controlled release and improved linearity for metoprolol tartrate in comparison
to two-layered tablet formulation. 相似文献
20.
Max R. Taylor Lucy A. Lawson Virginia G. Lockard William R. Lockwood 《Mycopathologia》1984,88(2-3):173-180
Electron microscopic examination of yeasts of Blastomyces dermatitidis, exposed in vitro to concentrations of lidocaine that occur when the drug is used for topical anesthesia, showed that lidocaine rapidly damaged intracellular structures. The extent of damage was dependent on the concentration of drug and length of exposure. The observed ultrastructural changes were very similar to those reported for other drugs that directly damage membranes. This relationship suggests that the antifungal effect of lidocaine is the result of direct membrane damage. 相似文献