Study of the critical points in combined matrix tablets containing both inert and swelling excipients

2019 ◽  
Vol 52 ◽  
pp. 885-894 ◽  
Author(s):  
Ángela Aguilar-de-Leyva ◽  
Maria Dolores Campiñez ◽  
Flavia Jost ◽  
Miguel Gavira ◽  
Isidoro Caraballo
Keyword(s):  
Critical Points ◽  
Matrix Tablets ◽  
Combined Matrix

Study of the critical points and the role of the pores and viscosity in carbamazepine hydrophilic matrix tablets

2012 ◽  
Vol 80 (1) ◽  
pp. 136-142 ◽  
Author(s):  
Ángela Aguilar-de-Leyva ◽  
Celia Cifuentes ◽  
Ali R. Rajabi-Siahboomi ◽  
Isidoro Caraballo
Keyword(s):  
Critical Points ◽  
Matrix Tablets ◽  
Hydrophilic Matrix

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Critical points of metallic plasmas and electrolytes

2000 ◽  
Vol 10 (PR5) ◽  
pp. Pr5-373-Pr5-376 ◽  
Author(s):  
A. A. Likalter ◽  
H. Schneidenbach
Keyword(s):  
Critical Points

Effects of release modifier on Carvedilol release from Kollidon SR based matrix

2012 ◽  
Vol 1 (8) ◽  
pp. 186 ◽  
Author(s):  
Urmi Das ◽  
Mohammad Salim Hossain
Keyword(s):  
Drug Release ◽  
Sustained Release ◽  
Microcrystalline Cellulose ◽  
Matrix Tablets ◽  
Dissolution Time ◽  
Release Mechanism ◽  
Matrix Tablet ◽  
Weight Variation ◽  
The Matrix ◽  
Tablet Formulations

<p>Sustained release Carvedilol matrix tablets constituting Kollidon SR were developed in this study in an attempt to investigate the effect of release modifiers on the release profile of Carvedilol from matrix. Three matrix tablet formulations were prepared by direct compression of Kollidon SR in combination with release modifier (HPMC and Microcrystalline Cellulose) and magnesium stearate. Tablets containing only Kollidon SR with the active ingredient demonstrated a rapid rate of drug release. Incorporation of HPMC in the matrix tablet prolonged the release of drug but incorporation of Microcrystalline Cellulose showed superimposable release pattern with an initial burst effect as confirmed by mean dissolution time and Higuchi release rate data. After 7 hours of dissolution, Carvedilol release from the matrix systems were 91.42%, 83.41%, from formulation F1 and F2 respectively. Formulation F3 exhibited 100 % release at 4 hours. All the tablet formulations showed acceptable pharmaco-technical properties and complied with the in-house specifications for tablet weight variation, friability, hardness, thickness, and diameter. Prepared tablets also showed sustained release property for carvedilol. The drug release mechanism from the matrix tablets of F1 and F2 was found to be followed by Fickian and F3 by Non-Fickian mechanism.</p><p>DOI: <a href="http://dx.doi.org/10.3329/icpj.v1i8.11095">http://dx.doi.org/10.3329/icpj.v1i8.11095</a></p> <p>International Current Pharmaceutical Journal 2012, 1(8): 186-192</p>

Application of graphical analysis of taxonomical structure of diatom complexes in identification of critical conditions of the Neopleistocene lakes (on the example of Bibirevo section)

2019 ◽  
pp. 78-87
Author(s):  
Elena V. Bespalova
Keyword(s):  
Lake Sediments ◽  
Critical Points ◽  
Graphical Analysis ◽  
Volga Region ◽  
Critical Conditions ◽  
Ancient Lake ◽  
Diatom Complexes

Ancient lake sediments of Bibirevo section in the Yaroslavl and Kostroma Volga region are studied by means of graphical analysis of taxonomical structure of diatom complexes. This method allowed to record critical points (change of areas of stability) in the development of a Neopleistocene lake during the transition from stage to stage, as well as from phase to phase.

Some features of phase transitions in solutions with two critical points

1996 ◽  
Vol 166 (6) ◽  
pp. 683-685 ◽  
Author(s):  
K.V. Kovalenko ◽  
S.V. Krivokhizha ◽  
Immanuil L. Fabelinskii ◽  
L.L. Chaikov
Keyword(s):  
Phase Transitions ◽  
Critical Points
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