First order release rate from porous PLA microspheres with limited exit holes on the exterior surface

2000 ◽  
Vol 66 (1) ◽  
pp. 27-38 ◽  
Author(s):  
T. Ehtezazi ◽  
C. Washington ◽  
C.D. Melia
Keyword(s):  
Release Rate ◽  
Exterior Surface ◽  
First Order ◽  
Order Release

Ionotropically Gelled Bicontinuous Cubic Phase as a Matrix for Controlled Release

1993 ◽  
Vol 331 ◽  
Author(s):  
S. Puvvada ◽  
J. Naciri ◽  
B. R. Ratna
Keyword(s):  
Release Rate ◽  
Release Profile ◽  
Water Soluble ◽  
Cubic Phase ◽  
First Order ◽  
On Demand ◽  
Release Studies ◽  
Order Release ◽  
Bicontinuous Cubic ◽  
Soluble Polysaccharide

AbstractRelease studies from a lipid-based matrix, known as the bicontinuous cubic phase, are presented. This matrix consists of nano-sized pores within which various proteins and drugs can be dispersed and subsequently released to the exterior. To control the release rate, the aqueous pores of the cubic phase were gelled using sodium alginate, a water soluble polysaccharide. Studies show that the release rate is significantly lowered upon gelation and the first order release profile exhibited by the ungelled cubic phase is converted to a zeroorder linear profile. Further, it has been shown that the release trends can be reversed by degelation. This opens up the possibility of releasing large quantities of the protein when required (drugs on demand concept) by degelling the gelled samples.

Metabolism of 75Se-selenite by human whole blood in vitro

1969 ◽  
Vol 47 (8) ◽  
pp. 791-797 ◽  
Author(s):  
Melvin Lee ◽  
Alice Dong ◽  
Joyce Yano
Keyword(s):  
Plasma Protein ◽  
Human Blood ◽  
Release Rate ◽  
Whole Blood ◽  
Human Whole Blood ◽  
First Order ◽  
First Order Kinetics ◽  
Altered Form

When 75Se, as selenite, is added to human blood it is rapidly taken up by the cells (50–70% within 1–2 min) and is then released into the plasma so that most of the radioactivity is in the plasma by 15–20 min. Uptake is inhibited by 10−3 M cyanide. The release of radioactivity from the cells is inhibited by 10−3 M para-chloromercuribenzoate and by 10−3 M iodoacetamide, although these agents do not affect uptake. Azide and 2,4-dinitrophenol (at 10−3 M) do not affect either process. Large quantities of sulfite, sulfate, and selenate (1000 times as much S or Se as 75Se) do not affect uptake or release, but large amounts of selenite (1000 times) inhibit release. The release rate follows first-order kinetics and increases with temperature. 75Se released from cells is bound by a plasma protein but can be removed from the protein by treatment with cysteine. Studies suggest that the released selenium is in an altered form or state, although this product has not been characterized. A hypothetical pathway for the metabolism of selenium is presented to account for the observations.

scholarly journals Formulation and In vitro Evaluation of Eudragit RL 100 Loaded Fexofenadine HCl Microspheres

2016 ◽  
Vol 19 (1) ◽  
pp. 58-67
Author(s):  
Paroma Arefin ◽  
Ikramul Hasan ◽  
Md Shfiqul Islam ◽  
Md Selim Reza
Keyword(s):  
Drug Release ◽  
Release Rate ◽  
Encapsulation Efficiency ◽  
Release Kinetics ◽  
Drug Loading ◽  
Release Mechanism ◽  
Order Release ◽  
Eudragit Rl ◽  
Fexofenadine Hcl

The present study deals with the formulation and evaluation of Fexofenadine hydrochloride (HCl) loaded sustained release microspheres by emulsion solvent evaporation method with Eudragit RL 100. The effects of percent drug loading on drug encapsulation efficiency, drug content and drug release rate were assessed. In vitro dissolution study was performed spectrophotometrically according to USP paddle method using phosphate buffer (pH 6.8) for 10 hours. The release rate of Fexofenadine HCl from the microspheres was significantly increased with the increase of drug loading. The drug release patterns were simulated in different kinetic orders such as zero order release kinetics, first order release kinetics, Higuchi release kinetics, Korsmeyer-Peppas release kinetics and Hixson-Crowell release kinetics to assess the release mechanism and Higuchi release kinetics was found to be the predominant release mechanism. Morphological changes due to different drug loading were assessed by scanning electron microscopic (SEM) technique. Differential scanning calorimetry and fourier transform infra-red (FT-IR) spectroscopy was performed to evaluate compatibility of drug with the polymer. A statistically significant variation indrug encapsulation efficiency and release rate was observed for variation in drug loading.Bangladesh Pharmaceutical Journal 19(1): 58-67, 2016

Thermal Properties of Pressure Sensitive MF Resin Microcapsules Containing CVL

2013 ◽  
Vol 746 ◽  
pp. 321-324
Author(s):  
Zhao Hui Zhen ◽  
Zheng Shun Wang
Keyword(s):  
Weight Loss ◽  
Thermal Properties ◽  
Heat Resistance ◽  
Production Process ◽  
Zero Order ◽  
First Order ◽  
Severe Weight Loss ◽  
Pressure Sensitive ◽  
Order Release ◽  
Zero Order Release

The paper studied thermal properties of MF-resin microcapsules. The paper established the non-liquid release dynamics equation in ideal mode. The results indicated at 400°C or so microcapsules began to severe weight loss, which explained the heat resistance of microcapsule could completely satisfy the requirement of coating production process. The results also showed the microcapsule thermal weight loss was in line with zero-order release before 373°C, and after 373°C accorded with first-order release dynamics equation.

An analysis of first-order release kinetics from albumin microspheres

1992 ◽  
Vol 9 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Jun'Ichi Okada ◽  
Yumi Masuyama ◽  
Tamotsu Kondo
Keyword(s):  
Release Kinetics ◽  
Albumin Microspheres ◽  
First Order ◽  
Order Release

scholarly journals Tailoring α/β Ratio of Pollen-Like Anhydrous Lactose as Ingredient Carriers for Controlled Dissolution Rate

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1049
Author(s):  
Jia Xiang ◽  
Bo Wang ◽  
Le Fu ◽  
Chuanpin Chen ◽  
Wenjie Liu ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Xrd Analysis ◽  
Drug Dissolution ◽  
Pore Width ◽  
Dsc Analysis ◽  
Melting Points ◽  
Release Rates ◽  
First Order ◽  
Order Release ◽  
Anhydrous Lactose

Lactose is a commonly used excipient with two isomers. Different isomers have different properties, especially in terms of solubility. This work is mainly to explore the influence of different a/β ratio lactose on drug dissolution. This work has developed novel mesoporous pollen-like lactose anhydrous with tailored α/β ratios as ingredient carriers for controlled dissolution rate. The produced lactose carriers are pollen-like with a particle size of ~15 μm and a mean pore width of ~30 nm. β-lactose anhydrous has a unique FTIR-peak at 948 cm−1, whereas α-lactose anhydrous shows a unique FTIR-peak at 855 cm−1. DSC analysis suggests that the pollen-like α/β-lactose crystals are polymorphs with unique peaks of melting points. XRD analysis suggests that (5:5)α/β-lactose polymorph has high crystalline purity. The loading efficiency (30.6–33.4% w/w) of acetamidophenol within the nanoporous lactose particles is dependent on the surface structure and pore volumes—the pore volumes were found to be 0.0209–0.0380 cm3/g. The release rates of acetamidophenol are lower for lactose with high α/β ratios. The lactose solubility and the first-order release constant can be tailored by changing the proportion of β-lactose in the pollen-like lactose carriers.

scholarly journals In vitro Release Kinetic Study of Theophylline from Kollidon SR Polymer Based Matrix Tablet

2015 ◽  
Vol 14 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Abul Kalam Lutful Kabir ◽  
Shimul Halder ◽  
Abu Shara Shamsur Rouf
Keyword(s):  
Release Rate ◽  
Release Kinetics ◽  
Zero Order ◽  
In Vitro Dissolution ◽  
Release Mechanism ◽  
Matrix Tablet ◽  
Medium Ph ◽  
First Order ◽  
Tablet Matrix

Controlled release tablet matrix of theophylline was prepared with kollidon SR, a spray dried powder grade polymer (polyvinyl acetate and povidone based matrix rate retarding hydrophobic materials) by utilizing direct compression technique. Different proportion of kollidon SR was used to develop the matrix builder in the five proposed formulations (F-1 to F-5) for the study of release rate retardant effect at 10, 12, 15, 18 and 21% of total weight of matrix tablet, respectively. The in vitro dissolution study of the matrices of those proposed tablet formulations were carried out in simulated gastric medium (pH 1.3) for first two hours and then in simulated intestinal medium (pH 6.8) for 6 hours using USP dissolution apparatus II (paddle method). The formulation F-3 (using 15% polymer) and F-4 (using 18 % polymer) met the optimum release profiles of active ingredient for 8 hr period of total study. The release kinetics for theophylline was plotted against zero order, first order and Higuchi release rate kinetics to evaluate the release mechanism of drug from the formulated tablet matrix. The release kinetics of formulation F-3 and F-4 was followed very closely by Higuchi release rate kinetic order than other kinetics such as zero order and first order kinetics which has been reflected the type of drug release from the tablet matrix by diffusion as well as erosion mechanism.Dhaka Univ. J. Pharm. Sci. 14(1): 43-48, 2015 (June)

scholarly journals In vitro release kinetics study of Esomeprazole Magnesium Trihydrate tablet available in Bangladesh and comparison with the originator brand (Nexium®)

1970 ◽  
Vol 4 (1) ◽  
pp. 79-83
Author(s):  
Shimul Halder ◽  
Madhabi Lata Shuma ◽  
Abul Kalam Lutful Kabir ◽  
Abu Shara Shamsur Rouf
Keyword(s):  
Release Kinetics ◽  
Zero Order ◽  
Kinetics Study ◽  
Medium Ph ◽  
First Order ◽  
Order Release ◽  
Originator Brand ◽  
E6 And E7 ◽  
Esomeprazole Magnesium

The main aim of present investigation was to study the dissolution pattern of most commercially available formulations of Esomeprazole in Bangladesh. Commercially available ten national brands and originator brand of esomeprazole magnesium trihydrate tablets were studied in simulated gastric medium (pH 1.2) for first 15 minutes and simulated intestinal medium (pH 6.8) for next 30 minutes time period using USP reference dissolu-tion apparatus (Type II). No brands met the dissolution pattern like the originator brand (E1). But three brands (E3, E6 and E7) were found to be very close to it in terms of dissolution pattern. One brand E11 was found to be sub-standard compared to originator one. Drug release profiles were analyzed for zero order, first order and Higuchi equation to reveal the release kinetics perspective of Esomeprazole magnesium trihydrate enteric coated tablets. It was found that first order kinetics was predominant for E1 (Originator Brand). Zero order and Higuchi release kinetics was predominant release mechanism than first order release kinetics for E2, E4 and E11. First order release kinetics was predominant for rest of the brands (E3, E5, E6, E7, E8, E9 and E10). It was found that drug release of those brands followed moderately diffusion method and concentration dependant from the dosage form. Among all of these locally manufactured Esomeprazole brands E3, E6 and E7 showed compatible dissolution pattern and release kinetics compared with the originator brand. Key words: In vitro dissolution; Market preparations; Kinetics study; Esomeprazole; National brand; Originator brand. DOI: http://dx.doi.org/10.3329/sjps.v4i1.8875 SJPS 2011; 4(1): 79-83

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