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1.
The aim of the present investigation was to develop oral controlled release matrix tablet formulations of isoniazid using
hydroxypropyl methylcellulose (HPMC) as a hydrophilic release retardant polymer and to study the influence of various formulation
factors like proportion of the polymer, polymer viscosity grade, compression force, and release media on the in vitro release characteristics of the drug. The formulations were developed using wet granulation technology. The in vitro release studies were performed using US Pharmacopoeia type 1 apparatus (basket method) in 900 ml of pH 7.4 phosphate buffer
at 100 rpm. The release kinetics was analyzed using Korsmeyer–Peppas model. The release profiles were also analyzed using
statistical method (one-way analysis of variance) and f
2 metric values. The release profiles found to follow Higuchi’s square root kinetics model irrespective of the polymer ratio
and the viscosity grade used. The results in the present investigation confirm that the release rate of the drug from the
HPMC matrices is highly influenced by the drug/HPMC ratio and viscosity grade of the HPMC. Also, the effect of compression
force and release media was found to be significant on the release profiles of isoniazid from HPMC matrix tablets. The release
mechanism was found to be anomalous non-Fickian diffusion in all the cases. In the present investigation, a series of controlled
release formulations of isoniazid were developed with different release rates and duration so that these formulations could
further be assessed from the in vivo bioavailability studies. The formulations were found to be stable and reproducible. 相似文献
2.
The purpose of this research was to design oral controlled release (CR) matrix tablets of zidovudine (AZT) using hydroxypropyl
methylcellulose (HPMC), ethyl cellulose (EC) and carbopol-971P (CP) and to study the effect of various formulation factors
on in vitro drug release. Release studies were carried out using USP type 1 apparatus in 900 ml of dissolution media. Release kinetics
were analyzed using zero-order, Higuchi’s square root and Ritger–Peppas’ empirical equations. Release rate decreased with
increase in polymer proportion and compression force. The release rate was lesser in formulations prepared using CP (20%)
as compared to HPMC (20%) as compared to EC (20%). No significant difference was observed in the effect of pH of dissolution
media on drug release from formulations prepared using HPMC or EC, but significant difference was observed in CP based formulations.
Decrease in agitation speed from 100 to 50 rpm decreased release rate from HPMC and CP formulations but no significant difference
was observed in EC formulations. Mechanism of release was found to be dependent predominantly on diffusion of drug through
the matrix than polymer relaxation incase of HPMC and EC formulations, while polymer relaxation had a dominating influence
on drug release than diffusion incase of CP formulations. Designed CR tablets with pH independent drug release characteristics
and an initial release of 17–25% in first hour and extending the release up to 16–20 h, can overcome the disadvantages associated
with conventional tablets of AZT. 相似文献
3.
Esra Baloğlu Sinem Y. Karavana Ismail Yuksel Hyusein Timur Köse 《AAPS PharmSciTech》2010,11(1):181-188
Gel formulations of mebeverine hydrochloride (MbHCl) containing hydroxypropylmethylcellulose (HPMC), metolose (MTL), and poloxamer
407 (PLX) were prepared to be used in the treatment of different oral painful conditions. HPMC was used as a mucoadhesive
gel base while MTL and PLX were used to prepare sol–gel thermosensitive gels. MTL and PLX formulations showed proper sol–gel
transition temperature for intraoral application. Formulations were evaluated in terms of their viscosity, mechanical properties,
mucoadhesivity, stability, and in vitro drug release. The formulation prepared with 2% of HPMC K100M provided the highest viscosity at room temperature. However,
the viscosity of HPMC–PLX mixture showed a significant increase at body temperature. The greatest mucoadhesion was also noted
in HPMC–PLX combinations. Texture profile analysis exhibited the differences of the adhesion, hardness, elasticity, cohesiveness,
and compressibility of the formulations. The release profiles of MbHCl were obtained, and non-Fickian release was observed
from all the formulations. The formulations were stored at different temperature and relative humidity. No significant changes
were observed at the end of the 3 months. HPMC–PLX formulation of MbHCl was chosen for in vivo studies, and it remained longer than dye solution on the rabbit’s intraoral mucosal tissue. It was found worthy of further
clinical evaluation. 相似文献
4.
The objective of the present study was to develop once-daily sustained-release matrix tablets of nicorandil, a novel potassium
channel opener used in cardiovascular diseases. The tablets were prepared by the wet granulation method. Ethanolic solutions
of ethylcellulose (EC), Eudragit RL-100, Eudragit RS-100, and polyvinylpyrrolidone were used as granulating agents along with
hydrophilic matrix materials like hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose, and sodium alginate.
The granules were evaluated for angle of repose, bulk density, compressibility index, total porosity, and drug content. The
tablets were subjected to thickness, diameter, weight variation test, drug content, hardness, friability, and in vitro release
studies. The granules showed satisfactory flow properties, compressibility, and drug content. All the tablet formulations
showed acceptable pharmacotechnical properties and complied with in-house specifications for tested parameters. According
to the theoretical release profile calculation, a oncedaily sustained-release formulation should release 5.92 mg of nicorandil
in 1 hour, like conventional tablets, and 3.21 mg per hour up to 24 hours. The results of dissolution studies indicated that
formulation F-I (drug-to-HPMC, 1∶4; ethanol as granulating agent) could extend the drug release up to 24 hours. In the further
formulation development process, F-IX (drug-to-HPMC, 1∶4; EC 4% wt/vol as granulating agent), the most successful formulation
of the study, exhibited satisfactory drug release in the initial hours, and the total release pattern was very close to the
theoretical release profile. All the formulations (except F-IX) exhibited diffusion-dominated drug release. The mechanism
of drug release from F-IX was diffusion coupled with erosion. 相似文献
5.
Kiran S. Bhise Ravindra S. Dhumal Biradar Shailesh Anant R. Paradkar Shivajirao S. Kadam 《AAPS PharmSciTech》2010,11(1):226-232
The purpose of this research was to address the utility of rheological study in understanding the influence of oppositely
charged polymers on release of naproxen sodium encapsulated in chitosan particles. The interaction between oppositely charged
κ-carrageenan (κ-Ca) and chitosan leads to relatively higher gel strength, which is proportional to the ability to retard
the drug release at acidic pH. The oscillatory tests within the linear viscoelastic range where the stress is proportional
to the applied strain were performed on the hydrated sample matrices containing chitosan-naproxen sodium spray-dried complexes
and k-Ca or hydroxypropyl methylcellulose (HPMC) in various ratios. It was observed that the effect of pH change on the dynamic
moduli in spray-dried complexes containing κ-Ca was much stronger than that with HPMC reflecting presence of strong ionic
interaction between κ-Ca and chitosan. The combination of oppositely charged polymers in different ratios proved to be useful
in modulating the rheological properties of the hydrated formulations and their release-retarding properties. Dynamic moduli
can be used to measure gel strength and are significant for the interpretation of oral sustained release spray-dried complexes. 相似文献
6.
Chaitanya Yogananda Gujjar Balaramesha Chary Rallabandi Ramesh Gannu Vallabh Subashrao Deulkar 《AAPS PharmSciTech》2016,17(2):350-357
Alcohol-induced dose dumping is a serious concern for the orally administered prolonged release dosage forms. The study was designed to optimize the independent variables, propylene glycol alginate (PGA), Eudragit RS PO (ERS) and coating in mucoadhesive quetiapine prolonged release tablets 200 mg required for preventing the alcohol-induced dose dumping. Optimal design based on response surface methodology was employed for the optimization of the composition. The formulations are evaluated for in vitro drug release in hydrochloric acid alone and with 40% v/v ethanol. The responses, dissolution at 120 min without alcohol (R1) and dissolution at 120 min with alcohol (R2), were statistically evaluated and regression equations are generated. PGA as a hydrophilic polymeric matrix was dumping the dose when dissolutions are carried in 0.1 N hydrochloric acid containing 40% v/v ethanol. ERS addition was giving structural support to the swelling and gelling property of PGA, and thus, was reducing the PGA erosion in dissolution media containing ethanol. Among the formulations, four formulations with diverse composition were meeting the target dissolution (30–40%) in both the conditions. The statistical validity of the mathematical equations was established, and the optimum concentration of the factors was established. Validation of the study with six confirmatory runs indicated high degree of prognostic ability of response surface methodology. Further coating with ReadiLycoat was providing an additional resistance to the alcohol-induced dose dumping. Optimized compositions showed resistance to dose dumping in the presence of alcohol. 相似文献
7.
The purpose of this research was to prepare and evaluate sustained release mucoadhesive tablets of Itraconazole. It is practically
insoluble in aqueous fluids hence its solid dispersion with Eudragit E100 was prepared by spray drying. This was formulated
in matrix of hydrophilic mucoadhesive polymers Carbopol 934P (CP) and Methocel K4M (HPMC). The formulation was optimized using
a 32 factorial design. Amounts of CP and HPMC were taken as formulation variables for optimizing response variables i.e. mucoadhesion
and dissolution parameters. The optimized mucoadhesive formulation was orally administered to albino rabbits, and blood samples
collected were used to determine pharmacokinetic parameters. The solid dispersion markedly enhanced the dissolution rate of
itraconazole. The bioadhesive strength of formulation was found to vary linearly with increasing amount of both polymers.
Formulations exhibited drug release fitting Peppas model with value of n ranging from 0.61 to 1.18. Optimum combination of polymers was arrived at which provided adequate bioadhesive strength and
fairly regulated release profile. The experimental and predicted results for optimum formulations were found to be in close
agreement. The formulation showed C
max 1898 ± 75.23 ng/ml, t
max of the formulation was 2 h and AUC was observed to be 28604.9 ng h/ml 相似文献
8.
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
9.
Rui Li Peng Quan Dong-Fei Liu Fang-Di Wei Qing Zhang Qun-Wei Xu 《AAPS PharmSciTech》2009,10(4):1137-1144
The present work was aimed at the influence of ethanol on the complex formation of hydroxypropyl-β-cyclodextrin (HP-β-CD)
with oleanolic acid (OA) and ursolic acid (UA), two insoluble isomeric triterpenic acids. Phase solubility studies were carried
out to evaluate the solubilizing power of HP-β-CD, in association with ethanol, toward OA and UA. A mathematical model was
applied to explain and predict the solubility of OA and UA influenced by HP-β-CD and ethanol. The solid complexes were prepared
by evaporating the filtrate of samples which was prepared in different complexing media. The solubility of OA is much higher
than that of UA in all the tested aqueous solutions. The solubility of OA and UA can be increased over 900 and 200 times,
respectively, by forming complex with HP-β-CD. Ethanol (0.5%, v/v) can help the formation of OA-HP-β-CD complex, but is harmful to the formation of UA-HP-β-CD complex. Increasing solubility
in water can be achieved by adding ethanol into the complexing media, but the concentration of ethanol should be optimized.
The ring E of the chemical compounds has a great influence on the complexing process. 相似文献
10.
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
11.
The purpose of this work was to evaluate the potential of grewia gum (GG) as a suspending agent in pharmaceutical oral formulation using ibuprofen as model drug. Ibuprofen pediatric suspension (25 mg/5 mL) was formulated with grewia gum (0.5% w/v) as the suspending agent. Similar suspensions of Ibuprofen containing either sodium carboxymethylcellulose (Na-CMC) or hydroxymethylpropylcellulose (HPMC) were also produced. The suspensions were evaluated for ease of redispersion, sedimentation, rheological properties, and the effect of aging on the rheological properties at 25°C. The particle size and particle size distributions of the dispersed solute were determined. The redispersion time was 19, 11, and 0.5 min, respectively, for formulation containing Na-CMC, HPMC, and GG .The sedimentation volumes were 0.05, 0.05, and 0.125 mL, respectively, for Na-CMC, HPMC, and GG . Viscosities of suspensions at spindle speed of 25 rpm were of the order: GG > HPMC > Na-CMC when freshly prepared and of the order: HPMC > GG > Na-CMC within 6 months of storage. The particles size was 72.72, 73.82, 81.93, and 83.41 μm, respectively, for suspensions containing Na-CMC, ibuprofen alone, HPMC, and GG. Greatest hysteresis was observed in formulation containing HPMC. All the formulations were stable. It was our conclusion that the difference in the physicochemical properties of ibuprofen pediatric formulations was influenced more by the suspending agent used in the formulations than the drug. GG combined better redispersion with minimal changes in viscosity on storage compared to Na-CMC and HPMC as suspending agent. Thus GG may serve as a good suspending agent requiring no further aid in suspension redispersibility.KEY WORDS: grewia gum, oral pharmaceutical formulations, physicochemical properties, potential suspending agent 相似文献
12.
Ibrić S Jovanović M Djurić Z Parojcić J Petrović SD Solomun L Stupar B 《AAPS PharmSciTech》2003,4(1):62-70
The purpose of the present study was to model the effects of the concentration of Eudragit L 100 and compression pressure
as the most important process and formulation variables on the in vitro release profile of aspirin from matrix tables formulated
with Eudragit L 100 as matrix substance and to optimize the formulation by artificial neural network. As model formulations,
10 kinds of aspirin matrix tablets were prepared. The amount of Eudragit L 100 and the compression pressure were selected
as causal factors. In vitro dissolution time profiles at 4 different sampling times were chosen as responses. A set of release
parameters and causal factors were used as tutorial data for the generalized regression neural, network (GRNN) and analyzed
using a computer. Observed results of drug release studies indicate that drug release rates vary widely between investigated
formulations, with a range of 5 hours to more than 10 hours to complete dissolution. The GRNN model was optimized. The root
mean square value for the trained network was 1.12%, which indicated that the optimal GRNN model was reached. Applying the
generalized distance function method, the optimal tablet formulation predicted by GRNN was with 5% of Eudragit L 100 and tablet
hardness 60N. Calculated difference (f
1 2.465) and similarity (f
2 85.61) factors indicate that there is no difference between predicted and experimentally observed drug release profiles for
the optimal formulation. This work illustrates the potential for an artificial neural network, GRNN, to assist in development
of extended release dosage forms. 相似文献
13.
《Journal of liposome research》2013,23(2):181-198
AbstractThe efficacy of gel formulations containing free and liposomal foscarnet has been evaluated in a murine model of cutaneous Herpes simplex virus type-1 infection. Both formulations were applied topically 3 times daily for 4 days and initiated 24 h post-infection. The penetration of liposomes incorporated into the gel in infected skin tissues was better than that of liposomes dispersed in buffer. Therein, their localization mostly matched that of viral antigen detected by immunoperoxydase staining. Despite these facts, the efficacy of gel formulations of both free and liposomal foscarnet in preventing the development of a zosteriform rash in mice was similar. Electron microscopic examination revealed that liposomes incorporated into the gel formed aggregates together with the micelles of gel. Diffusion studies showed that liposomes were trapped within these aggregates and were hardly able to diffuse across a polycarbonate membrane. In addition, although the liposomes were shown to be highly stable in vitro, the formation of these aggregates destabilized their membrane resulting in a premature release of foscarnet from liposomes. The efficacy of both gel formulations was higher than that of solutions of free or liposomal foscarnet suggesting that the gel formulation is a suitable matrix for the delivery of drugs. Thus, strategies aimed at reducing the interaction of liposomes with the gel could be a convenient approach to improve the efficacy of liposome-encapsulated drug over the free drug. 相似文献
14.
The development of an optimized gastric floating drug delivery system is described. Statistical experimental design and data
analysis using response surface methodology is also illustrated. A central, composite Box-Wilson design for the controlled
release of calcium was used with 3 formulation variables: X1 (hydroxypropyl methylcellulose [HPMC] loading), X2 (citric acid loading), and X3 (magnesium stearate loading). Twenty formulations were prepared, and dissolution studies and floating kinetics were performed
on these formulations. The dissolution data obtained were then fitted to the Power Law, and floating profiles were analyzed.
Diffusion exponents obtained by Power Law were used as targeted response variables, and the constraints were placed on other
response variables. All 3 formulation variables were found to be significant for the release properties (P<,05), while only HPMC loading was found to be significant for floating properties. Optimization of the formulations was achieved
by applying the constrained optimization. The optimized formulation delivered calcium at the release rate of 40 mg/hr, with
predicted n and T50% values at 0.93 and 3.29 hours, respectively. Experimentally, calcium was observed to release from the optimized formulation
with n and T50% values of 0.89 (±0.10) and 3.20 (±0.21) hours, which showed an excellent agreement. The quadratic mathematical model developed
could be used to further predict formulations with desirable release and floating properties. 相似文献
15.
Dhaval P. Patel Chitral Mallikarjuna Setty Gaurav N. Mistry Santnu L. Patel Tarun J. Patel Pritesh C. Mistry Amar K. Rana Pritesh K. Patel Rishabh S. Mishra 《AAPS PharmSciTech》2009,10(2):437-442
Transdermal films of the furosemide were developed employing ethyl cellulose and hydroxypropyl methylcellulose as film formers.
The effect of binary mixture of polymers and penetration enhancers on physicochemical parameters including thickness, moisture
content, moisture uptake, drug content, drug–polymer interaction, and in vitro permeation was evaluated. In vitro permeation study was conducted using human cadaver skin as penetration barrier in modified Keshary–Chein diffusion cell.
In vitro skin permeation study showed that binary mixture, ethyl cellulose (EC)/hydroxypropyl methylcellulose (HPMC), at 8.5:1.5 ratio
provided highest flux and also penetration enhancers further enhanced the permeation of drug, while propylene glycol showing
higher enhancing effect compared to dimethyl sulfoxide and isopropyl myristate. Different kinetic models, used to interpret
the release kinetics and mechanism, indicated that release from all formulations followed apparent zero-order kinetics and
non-Fickian diffusion transport except formulation without HPMC which followed Fickian diffusion transport. Stability studies
conducted as per International Conference on Harmonization guidelines did not show any degradation of drug. Based on the above
observations, it can be reasonably concluded that blend of EC–HPMC polymers and propylene glycol are better suited for the
development of transdermal delivery system of furosemide. 相似文献
16.
Different hydroxypropyl methylcellulose (HPMC)/anhydrous dibasic calcium phosphate (ADCP) matrix tablets have been developed aiming to evaluate the influence of both components ratio in the control release of a water-soluble drug (theophylline). In order to characterise the matrix tablets, swelling, buoyancy and dissolution studies have been carried out in different aqueous media (demineralised water, progressive pH medium, simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid). The HPMC/ADCP ratio has turned out to be the determinant in the matrix behaviour: the HPMC characteristic swelling behaviour was modulated, in some cases, by the ADCP characteristic acidic dissolution. When the HPMC/ADCP ratio was ≥0.69, buoyancy, continuous swelling and low theophylline dissolution rate from the matrices (H1, H2 and H3) were observed in all dissolution media. Consequently, these formulations could be adequate as gastro-retentive drug delivery systems. Additionally, HPMC/ADCP ratio ≤0.11 (H5 and H6) induces a pH-dependent drug release which could be applied to design control drug release enteric formulations (with a suitable enteric coating). Finally, a HPMC/ADCP ratio between 0.11 and 0.69 (H4) yield a gastrointestinal controlled drug release, due to its time-dependent buoyancy (7 h) and a total drug delivery in 17 h in simulated colonic fluid.Key words: anhydrous dibasic calcium phosphate, hydroxypropyl methylcellulose, matrix tablets, oral controlled release, theophylline 相似文献
17.
Psoriasis is a chronic, autoimmune skin disease affecting approximately 2% of the world's population. Clobetasol propionate
which is a superpotent topical corticosteroid is widely used for topical treatment of psoriasis. Conventional dosage forms
like creams and ointments are commonly prefered for the therapy. The purpose of this study was to develop a new topical delivery
system in order to provide the prolonged release of clobetasol propionate and to reduce systemic absorption and side effects
of the drug. Clobetasol propionate loaded-poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres were prepared by oil-in-water
emulsion–solvent evaporation technique. Particle size analysis, morphological characterization, DSC and XRD analyses and in vitro drug release studies were performed on the microparticle formulations. Emulgel formulations were prepared as an alternative
for topical delivery of clobetasol propionate. In vitro drug release studies were carried out from the emulgel formulations containing pure drug and drug-loaded microspheres. In
addition, the same studies were performed to determine the drug release from the commercial cream product of clobetasol propionate.
The release of clobetasol propionate from the emulgel formulations was significantly higher than the commercial product. In
addition, the encapsulation of clobetasol propionate in the PLGA microspheres significantly delayed the drug release from
the emulgel formulation. As a result, the decrease in the side effects of clobetasol propionate by the formulation containing
PLGA microspheres is expected. 相似文献
18.
An oral sustained release dosage form of cinnarizine HCl (CNZ) based on gastric floating matrix tablets was studied. The release
of CNZ from different floating matrix formulations containing four viscosity grades of hydroxypropyl methylcellulose, sodium
alginate or polyethylene oxide, and gas-forming agent (sodium bicarbonate or calcium carbonate) was studied in simulated gastric
fluid (pH 1.2). CNZ release data from the matrix tablets were analyzed kinetically using Higuchi, Peppas, Weibull, and Vergnaud
models. From water uptake, matrix erosion studies, and drug release data, the overall release mechanism can be explained as
a result of rapid hydration of polymer on the surface of the floating tablet and formation of a gel layer surrounding the
matrix that controls water penetration into its center. On the basis of in vitro release data, batch HP1 (CNZ, HPMC-K100LV, SBC, LTS, and MgS) was subjected to bioavailability studies in rabbits and was
compared with CNZ suspension. It was concluded that the greater bioavailability of HP1 was due to its longer retention in
the gastric environment of the test animal. Batch no. HP1 of floating tablet in rabbits demonstrated that the floating tablet
CNZ could be a 24-h sustained release formulation. 相似文献
19.
Yuejiang Liu Jinpeng Liu Xiaolin Zhang Ruodan Zhang Yongliang Huang Chunjie Wu 《AAPS PharmSciTech》2010,11(2):610-620
The objective of this study was to develop an ion-activated in situ gelling vehicle for ophthalmic delivery of matrine. The rheological properties of polymer solutions, including Gelrite, alginate,
and Gelrite/alginate solution, were evaluated. In addition, the effect of formulation characteristics on in vitro release and in vivo precorneal drug kinetic of matrine was investigated. It was found that the optimum concentration of Gelrite solution for
the in situ gel-forming delivery systems was 0.3% (w/w) and that for alginate solution was 1.4% (w/w). The mixture of 0.2% Gelrite and 0.6% alginate solutions showed a significant enhancement in gel strength at physiological
condition. On the basis of the in vitro results, the Gelrite formulations of matrine-containing alginate released the drug most slowly. For each tested polymer solution,
the concentration of matrine in the precorneal area was higher than that of matrine-containing simulated tear fluid (STF)
almost at each time point (p < 0.05). The area under the curve of formulation 16 (0.2%Gelrite/0.6%alginate) was 4.65 times greater than that of containing
matrine STF. Both the in vitro release and in vivo pharmacological studies indicated that the Gelrite/alginate solution had the better ability to retain drug than the Gelrite
or alginate solutions alone. The tested formulation was found to be almost non-irritant in the ocular irritancy test. The
overall results of this study revealed that the Gelrite/alginate mixture can be used as an in situ gelling vehicle to enhance ocular retention. 相似文献
20.
Enhancing and sustaining AMG 009 dissolution from a matrix tablet via microenvironmental pH modulation and supersaturation,
where poorly soluble acidic AMG 009 molecule was intimately mixed and compressed together with a basic pH modifier (e.g., sodium carbonate) and nucleation inhibitor hydroxypropyl methylcellulose K100 LV (HPMC K100 LV), was demonstrated previously. However, not all acidic or basic drugs are compatible with basic or acidic pH
modifiers either chemically or physically. The objective of this study is to investigate whether similar dissolution enhancement
of AMG 009 can be achieved from a bilayer dosage form, where AMG 009 and sodium carbonate are placed in a separate layer with
or without the addition of HPMC K100 LV in each layer. Study results indicate that HPMC K100 LV-containing bilayer dosage
forms gained similar dissolution enhancement as matrix dosage forms did. Bilayer dosage forms without HPMC K100 LV benefitted
the least from dissolution enhancement. 相似文献