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1.
The purpose of this study was to determine the factors that influence fill weight and weight variability of capsules produced
on the In-Cap and to assess any differences in terms of capsule defects between gelatin and HPMC (Quali-V) shells. The In-Cap
is an automatic tamping type capsule-filling machine and the low output of ≈3000 capsules/hour makes it ideal for early formulation
development and phase I/IIa clinical supplies manufacture. Four commonly used excipients (Avicel PH101, Avicel PH302, A-Tab,
and Prosolv HD90) and a poorly flowing drug blend were encapsulated at various pin settings and powder bed heights. The average
fill weight and coefficient of weight variation were determined. The percentage of defective capsules formed during encapsulation
was calculated. Results of the study showed that pin setting was critical for controlling the fill weight and the weight variation.
The order of pin setting with pin 1 (closer to the powder chute) set to a relatively higher position and pin 4 (before ejection)
set to a lower position was found to give higher fill weights with relatively lower weight variability. The powder bed height
influenced the fill weight for poorly flowing powders. The capsule machine speed did not appear to significantly influence
the fill weight. The fill weight and weight variation were found to depend on the flow property of the material. A large percentage
of defective capsules was obtained using HPMC shell size #00. Some of the commonly observed defects included split caps and
improperly closed filled capsules. In general, appropriate selection of pin settings and bed height can reduce the weight
variability seen, especially with poorly flowing high-dose formulations. 相似文献
2.
The purpose of the present study was to develop an optimized gastric floating drug delivery system (GFDDS) containing metoprolol
tartrate (MT) as a model drug by the optimization technique. A 23 factorial design was employed in formulating the GFDDS with total polymer content-to-drug ratio (X1), polymer-to-polymer ratio (X2), and different viscosity grades of hydroxypropyl methyl cellulose (HPMC) (X3) as independent variables. Four dependent variables were considered: percentage of MT release at 8 hours, T50%, diffusion coefficient, and floating time. The main effect and interaction terms were quantitatively evaluated using a mathematical
model. The results indicate that X1 and X2 significantly affected the floating time and release properties, but the effect of different viscosity grades of HPMC (K4M
and K10M) was nonsignificant. Regression analysis and numerical optimization were performed to identify the best formulation.
Fickian release transport was confirmed as the release mechanism from the optimized formulation. The predicted values agreed
well with the experimental values, and the results demonstrate the feasibility of the model in the development of GFDDS. 相似文献
3.
Laksmana FL Kok PJ Frijlink HW Vromans H Van der Voort Maarschalk K 《AAPS PharmSciTech》2008,9(3):891-898
The purpose of this research was to elucidate the significance of the changes in the mechanical and the volumetric properties
on the moisture diffusivity through the polymer films. The internal stress concept was adapted and applied to estimate the
relative impact of these property changes on the total stress experienced by a polymer film during storage. Hydroxypropyl
Methylcellulose free films were used as a model material prepared at various conditions and stored at different relative humidities.
The changes in the internal stress of these films due to the moisture sorption were studied. It was demonstrated that the
stress-relaxation of the films increases at increasing moisture content. At the point when there is a definite loss of stress
in the film, which is at moisture content higher than 6%, was shown to correlate with the significant increase of the moisture
diffusivity. Further investigations revealed that the loss of stress is especially due to the swelling of the polymer rather
than the changes in the inherent strain (the quotient between the tensile strength and the modulus of elasticity) of the HPMC
films. This implies that the impact of the moisture sorption on the diffusivity is predominantly via volume addition rather than via altering the mechanical properties. Additionally, the approach presented here also brings up a new application of the internal
stress concept, which in essence suggests the possibility to estimate the diffusion coefficient from the sorption isotherm
and the mechanical analysis data. 相似文献
4.
Quantification of protein concentration by the Bradford method in the presence of pharmaceutical polymers 总被引:1,自引:0,他引:1
We investigated how the Bradford assay for measurements of protein released from a drug formulation may be affected by a concomitant release of a pharmaceutical polymer used to formulate the protein delivery device. The main result is that polymer-caused perturbations of the Coomassie dye absorbance at the Bradford monitoring wavelength (595 nm) can be identified and corrected by recording absorption spectra in the region of 350–850 mm. The pharmaceutical polymers Carbopol and chitosan illustrate two potential types of perturbations in the Bradford assay, whereas the third polymer, hydroxypropylmethylcellulose (HPMC), acts as a nonperturbing control. Carbopol increases the apparent absorbance at 595 nm because the polymer aggregates at the low pH of the Bradford protocol, causing a turbidity contribution that can be corrected quantitatively at 595 nm by measuring the sample absorbance at 850 nm outside the dye absorption band. Chitosan is a cationic polymer under Bradford conditions and interacts directly with the anionic Coomassie dye and perturbs its absorption spectrum, including 595 nm. In this case, the Bradford method remains useful if the polymer concentration is known but should be used with caution in release studies where the polymer concentration may vary and needs to be measured independently. 相似文献
5.
Conclusion The present investigation described the influence of viscosity and content of HPMC on dipyridamole release using 32 full factorial design. All formulations had desired floating lag time (<2 minutes) regardless of viscosity and content of
polymeric matrices. Results of multiple regression analysis indicate that both factors significantly affect the diffusion
exponent (n), release rate constant (k), and percentage drug release at 1 hour, 4 hours, 6 hours, and 12 hour, (P<.05). Mechanism of drug release was found to be anomalous type to case-II transport depending upon the viscosity and content
of polymer. It was found that content of HPMC had a dominant role in the initial phase of drug release, while in the later
phase viscosity of HPMC Predominated.
Published: August 24, 2007 相似文献
6.
Siahi MR Barzegar-Jalali M Monajjemzadeh F Ghaffari F Azarmi S 《AAPS PharmSciTech》2005,6(4):E626-E632
The present study was performed to design oral controlled delivery systems for the water-soluble drug, verapamil hydrochloride,
using natural and semisynthetic polymers as carriers in the forms of 1- and 3-layer matrix tablets. Verapamil hydrochloride
1-layer matrix tablets containing hydroxypropylmethylcellulose, tragacanth, and acacia either alone or mixed were prepared
by direct compression technique. 3-layer matrix tablets were prepared by compressing the polymers as release retardant layers
on both sides of the core containing the drug. The prepared tablets were subjected to in vitro drug release studies. Tragacanth
when used as the carrier in the formulation of 1- and 3-layer matrices produced satisfactory release prolongation either alone
or in combination with the other 2 polymers. On the other hand, acacia did not show enough prolonging efficiency in 1- and
3-layer matrix tablets. The results also showed that the location of the polymers in the 3-layer tablets has a pronounced
effect on the drug release. Kinetic analysis of drug release from matrices exhibiting sustained release indicated that release
was predominantly attributable to the contribution made by Fickian diffusion, while the erosion/relaxation mechanisms had
a minor role in the release.
Published: December 7, 2005 相似文献
7.
An oral press-coated tablet was developed by means of direct compression to achieve the time-controlled disintegrating or
rupturing function with a distinct predetermined lag time. This press-coated tablet containing sodium diclofenac in the inner
core was formulated with an outer shell by different weight ratios of hydrophobic polymer of micronized ethylcellulose (EC)
powder and hydrophilic excipients such as spray-dried lactose (SDL) or hydroxypropyl methylcellulose (HPMC). The effect of
the formulation of an outer shell comprising both hydrophobic polymer and hydrophilic excipients on the time lag of drug release
was investigated. The release profile of the press-coated tablet exhibited a time period without drug release (time lag) followed
by a rapid and complete release phase, in which the outer shell ruptured or broke into 2 halves. The lag phase was markedly
dependent on the weight ratios of EC/SDL or EC/HPMC in the outer shell. Different time lags of the press-coated tablets from
1.0 to 16.3 hours could be modulated by changing the type and amount of the excipients. A semilogarithmic plot of the time
lag of the tablet against the weight ratios of EC/SDL or EC/HPMC in the outer shell demonstrated a good linear relationship,
withr=0.976 andr=0.982, respectively. The predetermined time lag prior to the drug release from a press-coated tablet prepared by using a
micronized EC as a retarding coating shell can be adequately scheduled with the addition of hydrophilic excipients according
to the time or site requirements. 相似文献
8.
9.
The purpose of this research was to develop the hydrodynamically balanced delivery system of Clarithromycin (CLA) which, after
oral administration should have the ability to prolong gastric residence time with the desired in vitro release profile for the localized action in the stomach, in the treatment of Helicobacter pylori (H.pylori) mediated peptic ulcer. By applying wet granulation technique floating tablets of Clarithromycin were prepared.
The proportion of sodium bicarbonate was varied to get the least possible lag time, also the polymer part varied to get the
desired release. In vivo radiographic studies were performed with Barium sulphate loaded formulation to justify the increased gastric residence time
of the dosage form in the stomach, based on the floating principle. The formulation developed using 66.2% Clarithromycin,
12% HPMC K4M polymer, 8% sodium bicarbonate gave floating lag time less than 3 min with a floating time of 12 h, and an in vitro release profile very near to the desired release. X-ray studies showed the enhanced gastric residence time of the tablet
to 220 ± 30 min. The mechanism of release of Clarithromycin from the floating tablets is anomalous diffusion transport and
follows zero order kinetics. In vivo radiographic studies suggest that the tablet has increased gastric residence time for the effective localized action of the
antibiotic (Clarithromycin) in the treatment of H.pylori mediated peptic ulcer. 相似文献
10.