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1.
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
2.
A novel experimental approach describing the integration of drug substance and drug production design using particle engineering
techniques such as sonocrystallization, high shear wet milling (HSWM) and dry impact (hammer) milling were used to manufacture
samples of an active pharmaceutical ingredient (API) with diverse particle size and size distributions. The API instability
was addressed using particle engineering and through judicious selection of excipients to reduce degradation reactions. API
produced using a conventional batch cooling crystallization process resulted in content uniformity issues. Hammer milling
increased fine particle formation resulting in reduced content uniformity and increased degradation compared to sonocrystallized
and HSWM API in the formulation. To ensure at least a 2-year shelf life based on predictions using an Accelerated Stability
Assessment Program, this API should have a D [v, 0.1] of 55 μm and a D [v, 0.5] of 140 μm. The particle size of the chief excipient in the drug product formulation needed to be close to that of the
API to avoid content uniformity and stability issues but large enough to reduce lactam formation. The novel methodology described
here has potential for application to other APIs. 相似文献
3.
Bilayer nicotine mucoadhesive patches were prepared and evaluated to determine the feasibility of the formulation as a nicotine
replacement product to aid in smoking cessation. Nicotine patches were prepared using xanthan gum or carbopol 934 as a mucoadhesive
polymers and ethyl cellulose as a backing layer. The patches were evaluated for their thickness, weight and content uniformity,
swelling behavior, drug–polymers interaction, adhesive properties, and drug release. The physicochemical interactions between
nicotine and the polymers were investigated by Fourier transform infrared (FTIR) spectroscopy. Mucoadhesion was assessed using
two-arm balance method, and the in vitro release was studied using the Franz cell. FTIR revealed that there was an acid base interaction between nicotine and carbopol
as well as nicotine and xanthan. Interestingly, the mucoadhesion and in vitro release studies indicated that this interaction was strong between the drug and carbopol whereas it was weak between the
drug and xanthan. Loading nicotine concentration to non-medicated patches showed a significant decrease in the mucoadhesion
strength of carbopol patches and no significant effect on the mucoadhesion strength of xanthan patches. In vitro release studies of the xanthan patches showed a reasonable fast initial release profile followed by controlled drug release
over a 10-h period. 相似文献
4.
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
5.
The aim of this work was the formulation and characterization of alginate (ALG)–doxycycline (DOX) hydrogel microparticles
(MPs) embedded into Pluronic F127 thermogel for DOX intradermal sustained delivery. ALG–DOX MPs were formed by adding a solution
of the drug into a 1.5% polymer solution while stirring. The MPs were cross-linked by dispersion into a 1.2% CaCl2 solution. Free MPs were characterized in terms of size, drug content, and release behavior by HPLC and UV–vis. DOX and hydrogel
MPs were embedded into PF127, PF127-HPMC, and PF127-Methocel thermogels. The thermogels were characterized in terms of gelling
time, morphology, and release behavior. A target release period of 4–7 days was considered optimal. The hydrogel MPs were
about 20 μm in size with 90% of the population <59 μm. Drug content was about 35% (w/w). DOX released rapidly from the MPs, 90% within 2 days. An expected faster release was observed for free DOX from the thermogels
with 80–90% of drug released after 3.5–4 h even in the presence of 1% HPMC or Methocel. The release was sustained after embedding
the MPs into PF127 and PF127-HPMC thermogels. In particular, the PF127-HPMC thermogel showed an almost linear release, reaching
80% after 3 days and 90% up to 6 days. Although a further characterization and formulation assessment is required to optimize
MP characteristics, ALG/DOX-loaded hydrogel MPs, when embedded into a PF127-HPMC thermogel, show a potential for achieving
a 7-day sustained release formulation for DOX intradermal delivery. 相似文献
6.
Sustained release mucoadhesive amoxicillin tablets with tolerance to acid degradation in the stomach were studied. The sustained-release
tablets of amoxicillin were prepared from amoxicillin coated with ethyl cellulose (EC) and then formulated into tablets using
chitosan (CS) or a mixture of CS and beta-cyclodextrin (CD) as the retard polymer. The effects of various (w/w) ratios of EC/amoxicillin, the particle sized of EC coated amoxicillin and the different (w/w) ratios of CS/CD for the retard polymer, on the amoxicillin release profile were investigated. The physicochemical properties
of the EC coated amoxicillin particles and tablets were determined by scanning electron microscopy, Fourier-transform infrared
spectroscopy, X-ray diffraction, and differential scanning calorimetry. The result showed that the release profiles of amoxicillin
were greatly improved upon coating with EC, while the inclusion of CD to the CS retardant additionally prolonged the release
of the drug slightly. Overall, a sustained release of amoxicillin was achieved using amoxicillin coated with EC at a (w/w) ratio of 1:1 and a particle size of 75–100 μm. Therefore, the tablet formulation of amoxicillin may be an advantageous alternative
as an orally administered sustained-release formulation for the treatment of peptic ulcers. 相似文献
7.
Considering the advantageous for the rectal administration of non-steroidal anti-inflammatory drugs, the objective of this
study was to formulate and evaluate rectal mucoadhesive hydrogels loaded with diclofenac-sodium chitosan (DFS-CS) microspheres.
Hydroxypropyl methylcellulose (HPMC; 5%, 6%, and 7% w/w) and Carbopol 934 (1% w/w) hydrogels containing DFS-CS microspheres equivalent to 1% w/w active drug were prepared. The physicochemical characterization revealed that all hydrogels had a suitable pH for rectal
application (6.5–7.4). The consistency of HPMC hydrogels showed direct proportionality to the concentration of the gelling
agent, while carbopol 934 gel showed its difficulty for rectal administration. Farrow’s constant for all hydrogels were greater
than one indicating pseudoplastic flow. In vitro drug release from the mucoadhesive hydrogel formulations showed a controlled drug release pattern, reaching 34.6–39.7% after
6 h. The kinetic analysis of the release data revealed that zero-order was the prominent release mechanism. The mucoadhesion
time of 7% w/w HPMC hydrogel was 330 min, allowing the loaded microspheres to be attached to the surface of rectal mucosa. Histopathological
examination demonstrated the lowest irritant response to the hydrogel loaded with DFS-CS microspheres in response to other
forms of the drug. 相似文献
8.
Summary The thickness of the pre-epithelial mucus layer has been measured in different gut segments of rats kept under normal (ad libitum) feeding conditions, and after 48 h of fasting, using cryostat sections and celloidin stabilization from samples containing
luminal contents. The mucus layer of the stomach, duodenum, jejunum, ileum, caecum, proximal colon, colon transversum, distal
colon and rectum was studied in five groups of male rats (10, 40, 70 and 150 days of age, and older). Underad libitum feeding conditions, a distinct and continuous mucus layer, with a thickness of more than 3 μm, was only observed in the colon
transversum, in the distal colon, in the rectum and in the stomach. No pre-epithelial mucus layer was observed in the duodenum
and jejunum where the glycocalix from the apical membrane of the superficial cells appeared to be in a direct contact with
the luminal ingesta. In the ileum, caecum and the proximal colon, the surface epithelium of the mucosa was only partly covered
by a mucus layer of highly variable thickness. After 48 h of fasting, a mucus layer of 28.8 ± 25.6 μm and 93.3 ± 59.4 μm thickness,
respectively, was found in the duodenum and jejunum of adult rats, but no increase in the thickness of the mucus layer was
observed in the rat hind gut. 相似文献
9.
Jaclyn Hosmer Rachel Reed M. Vitória L.B. Bentley Adwoa Nornoo Luciana B. Lopes 《AAPS PharmSciTech》2009,10(2):589-596
We evaluated the ability of microemulsions containing medium-chain glycerides as penetration enhancers to increase the transdermal
delivery of lipophilic (progesterone) and hydrophilic (adenosine) model drugs as well as the effects of an increase in surfactant
blend concentration on drug transdermal delivery. Microemulsions composed of polysorbate 80, medium-chain glycerides, and
propylene glycol (1:1:1, w/w/w) as surfactant blend, myvacet oil as the oily phase, and water were developed. Two microemulsions containing different concentrations
of surfactant blend but similar water/oil ratios were chosen; ME-lo contained a smaller concentration of surfactant than ME-hi
(47:20:33 and 63:14:23 surfactant/oil/water, w/w/w). Although in vitro progesterone and adenosine release from ME-lo and ME-hi was similar, their transdermal delivery was differently affected.
ME-lo significantly increased the flux of progesterone and adenosine delivered across porcine ear skin (4-fold or higher,
p < 0.05) compared to progesterone solution in oil (0.05 ± 0.01 μg/cm2/h) or adenosine in water (no drug was detected in the receptor phase). The transdermal flux of adenosine, but not of progesterone,
was further increased (2-fold) by ME-hi, suggesting that increases in surfactant concentration represent an interesting strategy
to enhance transdermal delivery of hydrophilic, but not of lipophilic, compounds. The relative safety of the microemulsions
was assessed in cultured fibroblasts. The cytotoxicity of ME-lo and ME-hi was significantly smaller than sodium lauryl sulfate
(considered moderate-to-severe irritant) at same concentrations (up to 50 μg/mL), but similar to propylene glycol (regarded
as safe), suggesting the safety of these formulations. 相似文献
10.
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
11.
Golam Kibria Monzurul Amin Roni Mohammad Shahriarul Absar Reza-ul Jalil 《AAPS PharmSciTech》2008,9(4):1240-1246
The present study was designed to investigate the effect of two plasticizers, i.e., triethyl citrate (TEC) and polyethylene
glycol 6000 (PEG 6000) on the in vitro release kinetics of diclofenac sodium from sustained-release pellets. Ammonio methacrylate copolymer type B (Eudragit RS
30 D) is used as the release-retarding polymer. Both plasticizers were used at 10% and 15% (w/w) of Eudragit RS 30 D. Pellets were prepared by powder layering technology and coated with Eudragit RS 30 D by air suspension
technique. Thermal properties of drug and drug-loaded beads were studied using differential scanning calorimeter (DSC). DSC
thermogram represented the identity of raw materials and exhibited no interaction or complexation between the active and excipients
used in the pelletization process. Dissolution study was performed by using USP apparatus 1. No significant difference was
observed among the physical properties of the coated pellets of different batches. When dissolution was performed as pure
drug, about 8.22% and 90% drug was dissolved at 2 h in 0.1 N HCl and at 30 min in buffer (pH 6.8), respectively. From all
formulations, the release of drug in acid media was very negligible (maximum 1.8 ± 0.08% at 2 h) but in buffer only 12% and
30% drug was released at 10 h from coated pellets containing TEC and PEG 6000, respectively, indicating that Eudragit RS 30
D significantly retards the drug release rate and that drug release was varied according to the type and amount of plasticizers
used. The amount of TEC in coating formulation significantly effected drug release (p < 0.001), but the effect of PEG 6000 was not significant. Formulations containing PEG 6000 released more drug (98.35 ± 2.35%)
than TEC (68.01 ± 1.04%) after 24 h. Different kinetic models like zero order, first order, and Higuchi were used for fitting
drug release pattern. Zero order model fitted best for diclofenac release in all formulations. Drug release mechanism was
derived with Korsmeyer equation. 相似文献
12.
Bajerová M Krejčová K Rabišková M Muselík J Dvořáčková K Gajdziok J Masteiková R 《AAPS PharmSciTech》2011,12(4):1348-1357
The aim of this study was to develop novel hydrogel-based beads and characterize their potential to deliver and release a
drug exhibiting pH-dependent solubility into distal parts of gastrointestinal (GI) tract. Oxycellulose beads containing diclofenac
sodium as a model drug were prepared by the ionotropic external gelation technique using calcium chloride solution as the
cross-linking medium. Resulting beads were characterized in terms of particle shape and size, encapsulation efficacy, swelling
ability and in vitro drug release. Also, potential drug–polymer interactions were evaluated using Fourier transform infrared spectroscopy. The
particle size was found to be 0.92–0.96 mm for inactive (oxycellulose only) and 1.47–1.60 mm for active (oxycellulose–diclofenac
sodium) beads, respectively. In all cases, the sphericity factor was between 0.70 and 0.81 with higher values observed for
samples containing higher polymer and drug concentrations. The swelling of inactive beads was found to be strongly influenced
by the pH and composition (i.e. Na+ concentration) of the selected media (simulated gastric fluid vs. phosphate buffer pH 6.8). The encapsulation efficiency of the prepared particles ranged from 58% to 65%. Results of dissolution
tests showed that the drug loading inside of the particles influenced the rate of its release. In general, prepared particles
were able to release the drug within 12–16 h after a lag time of 4 h. Fickian diffusion was found as the predominant drug release mechanism. Thus, this novel particulate system showed
a good potential to deliver drugs specifically to the distal parts of the human GI tract. 相似文献
13.
The effects of six different polyglycerol esters of fatty acids (PGEs) and two different particle sizes produced using various
processing parameters on the physicochemical properties and stability of the β-carotene emulsions during digestion in simulated
gastric fluid (SGF) were investigated. β-Carotene emulsions were prepared by high-pressure homogenization using β-carotene
(0.1% w/w) in soybean oil as the oil phase and 1% (w/w) PGE in Milli-Q water as the water phase. The particle size of β-carotene emulsions was measured by a laser diffraction technique,
and the stability of emulsions was interpreted in terms of the increase in particle size and span value of emulsion droplets
and the retention of β-carotene during digestion in SGF. The average particle size ranges of emulsions were 0.17 to 0.27 μm
for fine emulsions and 1.16 to 1.59 μm for coarse emulsions. In the prepared β-carotene emulsions, the particle size decreased
with increasing polymerization of the glycerol in PGEs, and the higher polymerization of the glycerol also increased the stability
of emulsions during digestion in SGF. Although the β-carotene content in the emulsions significantly decreased with increasing
digestion period, loss of β-carotene was more severe in unstable emulsions than in stable emulsions, suggesting that the particles
incorporated into droplets could provide some protective barrier for decreasing the β-carotene degradation. Therefore, β-carotene
emulsions stabilized by PGEs with high polymerization of the glycerol may be useful for further applications in food and drug
formulations. Decaglycerol monooleate (MO750) was demonstrated to be the most effective emulsifier in stabilizing β-carotene
emulsions in this study. 相似文献
14.
T. Dennis Thomas 《In vitro cellular & developmental biology. Plant》2009,45(5):591-598
Protoplast culture and plant regeneration of an important medicinal plant Tylophora indica were achieved through callus regeneration. Protoplasts were isolated from leaf mesophyll cells and cultured at a density
of 5 × 105 protoplasts per gram fresh weight, which is required for the highest frequency of protoplast division (33.7%) and plating
efficiency (9.3%). The first division was observed 2 d after plating and the second division after 4 d. Culture medium consists
of Murashige and Skoog (MS) liquid medium with 4 μM 2,4-D, 0.4 M mannitol and 3% (w/v) sucrose with pH adjusted to 5.8. After 45 d of culture at 25°C in the dark, protoplasts formed colonies consisting of about
100 cells. The protoplast-derived microcalli were visible to the naked eye within 60 d of culture and reached a size of 0.2–0.4 mm
in diameter after 90 d. Calli of 0.2–0.4-mm size were transferred to MS medium supplemented with 2,4-D (4 μM), 3% (w/v) sucrose and 0.8% (w/v) agar, formed friable organogenic calli (7-8 mm size) after 8 wk under incubation in normal light period supplemented with
200 μmol m−2 S−1 of day light fluorescent illumination. The calli were transferred to MS medium supplemented with thidiazuron (TDZ) (1–7 μM)
and naphthalene acetic acid (NAA) (0.2–0.4 μM) for regeneration. The calli developed shoot buds after 3–4 wk, and the frequencies
of calli-forming shoots varied from 5% to 44%. Optimum shoot regeneration occurred on MS medium supplemented with 5 μM TDZ
and 0.4 μM NAA. On this medium, 44% cultures responded with an average number of 12 shoots per callus. Whole plants were recovered
following rooting of shoots in 1/2 MS medium supplemented with 3 μM indole 3-butyric acid. 相似文献
15.
Ana Paula Badan Ribeiro Renato Grimaldi Luiz Antonio Gioielli Adenilson Oliveira dos Santos Lisandro Pavie Cardoso Lireny A. Guaraldo Gonçalves 《Food biophysics》2009,4(2):106-118
Blends of soybean oil (SO) and fully hydrogenated soybean oil (FHSBO), with 10, 20, 30, 40, and 50% (w/w) FHSBO content were interesterified under the following conditions: 20 min reaction time, 0.4% sodium methoxide catalyst,
and 500 rpm stirring speed, at 100 °C. The original and interesterified blends were examined for triacylglycerol composition,
thermal behavior, microstructure, crystallization kinetics, and polymorphism. Interesterification produced substantial rearrangement
of the triacylglycerol species in all the blends, reduction of trisaturated triacylglycerol content and increase in monounsaturated–disaturated
and diunsaturated–monosaturated triacylglycerols. Evaluation of thermal behavior parameters showed linear relations with FHSBO
content in the original blends. Blend melting and crystallization thermograms were significantly modified by the randomization.
Interesterification caused significant reductions in maximum crystal diameter in all blends, in addition to modifying crystal
morphology. Characterization of crystallization kinetics revealed that crystal formation induction period (τ
SFC) and maximum solid fat content (SFCmáx) were altered according to FHSBO content in the original blends and as a result of the random rearrangement. Changes in Avrami
constant (k) and exponent (n) indicated, respectively, that—as compared with the original blends—interesterification decreased crystallization velocities
and modified crystallization processes, altering crystalline morphology and nucleation mechanism. X-ray diffraction analyses
revealed that interesterification altered crystalline polymorphism. The interesterified blends showed a predominance of the
β′ polymorph, which is of more interest for food applications. 相似文献
16.
The myxosporean Thelohanellus
rhabdalestus n. sp. (Myxozoa: Bivalvulida), a parasite of the freshwater fish Rhabdalestes maunensis (Fower) collected from the Kwanza River, Angola, is described based on light and electron microscopical studies. The parasite
occurs in irregular, milky-whitish, cyst-like plasmodia (up to 0.8 mm in diameter) in close contact with the liver and heart.
The spores are pyriform, with slight tapering anterior and round posterior ends, and measure 16.8 ± 0.5 μm (n = 50) long,
10.2 ± 0.6 μm (n = 50) wide and 5.6 ± 0.8 μm (n = 25) thick. The spore wall is partly surrounded by a discontinuous, closely
adhered, external coat of electron-dense material of variable thickness (up to c.35 nm). A single flask-shaped polar capsule [7.2 ± 0.3 μm (n = 50) long and 4.0 ± 0.4 μm (n = 50) in diameter] lies close
to the apex of the spores and contains a polar filament with six or seven (rarely eight) coils oblique to its longitudinal
axis. Based on morphological and ultrastructural differences, compared with other members of Thelohanellus Kudo, 1933, and judging from the host-specificity of previously described species, we consider this species new to science.
This is the first reported myxosporean from the Angolan fauna. 相似文献
17.
The purpose of this work was to develop w/o emulsions that could be safely used to promote transdermal delivery of 5-fluorouracil
(5-FU). Two pseudo-ternary phase diagrams comprising oleoyl-macrogol glycerides, water, and a surfactant/co-surfactant (S/CoS)
mixture of lecithin, ethanol, and either coco glucoside or decyl glucoside were investigated for their potential to develop
promising 5-FU emulsions. Six systems were selected and subjected to thermodynamic stability tests; heat–cool cycles, centrifugation,
and finally freeze–thaw cycles. All systems passed the challenges and were characterized for transmission electron microscopy,
droplet size, rheological behavior, pH, and transdermal permeation through newly born mice skin in Franz diffusion cells.
The systems had spherical droplets ranging in diameter from 1.81 to 2.97 μm, pH values ranging from 7.50 to 8.49 and possessed
Newtonian flow. A significant (P < 0.05) increase in 5-FU permeability parameters as steady-state flux, permeability coefficient was achieved with formula
B5 comprising water (5% w/w), S/CoS mixture of lecithin/ethanol/decyl glucoside (14.67:12.15:18.18% w/w, respectively) and oleoyl-macrogol glycerides (50% w/w). When applied to shaved rat skin, this system was well tolerated with only moderate skin irritation that was recovered within
12 h. Indeed, minor histopathologic changes were observed after 5-day treatment. Further studies should be carried out, in
the future, to investigate the potentiality of this promising system to promote transdermal delivery of 5-FU through human
skin. 相似文献
18.
Pasquale Del Gaudio Paola Russo Maria Rosaria Lauro Paolo Colombo Rita P. Aquino 《AAPS PharmSciTech》2009,10(4):1178-1185
In this paper, ketoprofen and ketoprofen lysinate were used as model drugs in order to investigate release profiles of poorly
soluble and very soluble drug from sodium alginate beads manufactured by prilling. The effect of polymer concentration, viscosity,
and drug/polymer ratio on bead micromeritics and drug release rate was studied. Ketoprofen and ketoprofen lysinate loaded
alginate beads were obtained in a very narrow dimensional range when the Cross model was used to set prilling operative conditions.
Size distribution of alginate beads in the hydrated state was strongly dependent on viscosity of drug/polymer solutions and
frequency of the vibration. The release kinetics of the drugs showed that drug release rate was related with alginate concentration
and solubility of the drug. Alginate solutions with concentration higher than 0.50% (w/w) were suitable to prepare ketoprofen gastro-resistant formulation, while for ketoprofen lysinate alginate, concentration
should be increased to 1.50% (w/w) in order to retain the drug in gastric environment. Differential scanning calorimetry thermograms and Fourier transform
infrared analyses of drug-loaded alginate beads indicated complex chemical interactions between carboxyl groups of the drug
and polymer matrix in drug-loaded beads that contribute to the differences in release profile between ketoprofen and ketoprofen
lysinate. Total release of the drugs in intestinal medium was dependent on the solubility of the drug and was achieved between
4 and 6 h. 相似文献
19.
Ali Nokhodchi Ononuju N. Okwudarue Hadi Valizadeh Mohammad N. Momin 《AAPS PharmSciTech》2009,10(4):1243-1251
The aim of the present study was to explore the cogrinding technique as a tool to slow down the drug release from capsule
formulations. To this end, the physical mixtures of theophylline–magnesium stearate were prepared and subjected to different
milling times (1, 15, 30, 120 min). In order to investigate the effect of magnesium stearate concentration on drug release,
various concentrations of magnesium stearate (1%, 3%, 5%, and 10%, w/w) were used. The dissolution rate of the drug from coground samples and physical mixtures were determined at pH 6.5 according
to USP. The results showed that all coground formulations showed slower release rates than their physical mixture counterparts.
The effect of cogrinding time on the drug release was complex. Cogrinding time had no significant effect on drug release when
the amount of magnesium stearate was 1% (w/w). When the amount of magnesium stearate was increased from 1% to 3% and cogrinding time increased from 1 to 5 min, there
was a significant reduction in drug release. Beyond 5-min cogrinding, the drug release increased again. For coground samples
containing 5% or 10% (w/w) magnesium stearate, generally, the highest drug release was obtained at higher cogrinding time. This was due to a significant
increase in surface area of particles available for dissolution as proven by scanning electron microscopy results. Fourier
transform infrared and differential scanning calorimetry results ruled out any significant interaction between theophylline
and magnesium stearate in solid state. 相似文献
20.
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