Use of In Vitro Release Tests for the Prediction of the In Vivo Behavior and the Development of Flucytosine Controlled-Release Capsules

1995 ◽  
Vol 84 (5) ◽  
pp. 619-623 ◽  
Author(s):  
Jean‐Daniel Bonny ◽  
Masanori Kyowa
Drug Research ◽  
2017 ◽  
Vol 67 (11) ◽  
pp. 653-660 ◽  
Author(s):  
Marilena Vlachou ◽  
Angeliki Siamidi ◽  
Dimitrios Spaneas ◽  
Dimitrios Lentzos ◽  
Polixeni Ladia ◽  
...  

AbstractThe aim of the present investigation was to develop matrix tablet formulations for the in vitro controlled release of two new tuberculocidal adamantane aminoethers (compounds III and IV), congeneric to the adamantane derivative SQ109, which is in final clinical trials, and aminoethers (I) and (II), using carefully selected excipients, such as polyvinylpyrrolidone, sodium alginate and lactose. The tablets were prepared using the direct compression method and dissolution experiments were conducted using the US Pharmacopoeia type II apparatus (paddle method) in gastric and intestinal fluids. The results suggest that both analogues, albeit more lipophilic than SQ109, and aminoethers (I) and (II), have the requisite in vitro release characteristics for oral administration. In conclusion, these formulations merit further assessment by conducting in vivo studies, at a later stage.


1992 ◽  
Vol 85 (1-3) ◽  
pp. 65-73 ◽  
Author(s):  
Shigeru Aoki ◽  
Keizo Uesugi ◽  
Kimio Tatsuishi ◽  
Hiroshi Ozawa ◽  
Masanori Kayano

Author(s):  
Revathi M. ◽  
Indira Y.

This study elucidates the enhancement of the permeation of bosentan monohydrate through skin by encapsulating it in vesicles loaded transdermal delivery system. Niosomal vesicles were formulated by ether injection method. Formulation FN7 (span 60: cholesterol: poloxamer 401, 1.25:1:0.25) showed maximum entrapment efficiency of 96.7±0.037% and was optimized for loading in to transdermal system. Transdermal systems were formulated using both hydrophilic and hydrophobic polymers like HPMC, HEC and EC. Formulation F1 with HPMC was optimized based on in vitro release (99.21±1.45 %) and was further evaluated for ex-vivo permeation. The results indicate that the ex vivo release (98.13±1.65%) was as par with in vitro release and followed zero order super case- II transport mechanism. The in vivo studies were done on New Zealand male rabbits for oral and transdermal route. The results inferred no significant change in half-life of drug but a substantial difference in Tmax, AUC and MRT was observed in transdermal systems. A two fold increase in AUC was observed in transdermal route (18.609±7.251µg/ml/h) when compared to oral route (9.644±5.621µg/ml/h). A controlled release was attained up to 35h and reservoir effect was observed and this may be due to the barrier properties of skin. Drug encapsulated niosomes were released in to the skin by loosening the lipid layers and the surfactant acted as penetration enhancer. The study infers that niosomes loaded transdermal patches of bosentan monohydrate can enhance the bioavailability and provided controlled release for better therapeutic efficacy and safety of drug.


1987 ◽  
Vol 57 (02) ◽  
pp. 201-204 ◽  
Author(s):  
P Y Scarabin ◽  
L Strain ◽  
C A Ludlam ◽  
J Jones ◽  
E M Kohner

SummaryDuring the collection of samples for plasma β-thromboglobulin (β-TG) determination, it is well established that artificially high values can be observed due to in-vitro release. To estimate the reliability of a single β-TG measurement, blood samples were collected simultaneously from both arms on two separate occasions in 56 diabetic patients selected for a clinical trial. From each arm, blood was taken into two tubes containing an anticoagulant mixture with (tube A) and without (tube B) PGE!. The overall mean value of B-TG in tube B was 1.14 times higher than in tube A (p <0.01). The markedly large between-arms variation accounted for the most part of within-subject variation in both tubes and was significantly greater in tube B than in tube A. Based on the difference between B-TG values from both arms, the number of subjects with artifically high B-TG values was significantly higher in tube B than in tube A on each occasion (overall rate: 28% and 14% respectively). Estimate of between-occasions variation showed that B-TG levels were relatively stable for each subject between two occasions in each tube. It is concluded that the use of PGEi decreases falsely high B-TG levels, but a single measurement of B-TG does not provide a reliable estimate of the true B-TG value in vivo.


Author(s):  
Chukwuebuka Umeyor ◽  
Uchechukwu Nnadozie ◽  
Anthony Attama

This study seeks to formulate and evaluate a solid lipid nanoparticle-based, solidified micellar carrier system for oral delivery of cefepime. Cefepime has enjoyed a lot of therapeutic usage in the treatment of susceptible bacterial infections; however, its use is limited due to its administration as an injection only with poor patient compliance. Since oral drug administration encourage high patient compliance with resultant effect in improved therapy, cefepime was formulated as solid lipid microparticles for oral delivery using the concept of solidified micellar carrier system. The carrier system was evaluated based on particle yield, particle size and morphology, encapsulation efficiency (EE %), and thermal analysis using differential scanning calorimeter (DSC). Preliminary microbiological studies were done using gram positive and negative bacteria. In vitro release study was performed using biorelevant media, while in vivo release study was performed in white albino rats. The yield of solid lipid microparticles (SLM) ranged from 84.2 – 98.0 %. The SLM were spherical with size ranges of 3.8 ± 1.2 to 42.0 ± 1.4 µm. The EE % calculated ranged from 83.6 – 94.8 %. Thermal analysis showed that SLM was less crystalline with high potential for drug entrapment. Microbial studies showed that cefepime retained its broad spectrum anti-bacterial activity. In vitro release showed sustained release of cefepime from SLM, and in vivo release study showed high concentration of cefepime released in the plasma of study rats. The study showed that smart engineering of solidified micellar carrier system could be used to improve oral delivery of cefepime.


Author(s):  
Nagratna Dhople ◽  
P N Dandag ◽  
A P Gadad ◽  
C K Pandey ◽  
Masthiholimath V S

A gastroretentive sustained release system of itopride hydrochloride was formulated to increase the gastric residence time and modulate its release behavior. Itopride hydrochloride is a prokinetic drug used in the treatment of gastroeosophageal reflux disease, Non-ulcer dyspepsia and as an antiemetic. Hence, itopride hydrochloride beads were prepared by emulsion gelation method by employing low methoxy pectin and sodium alginate as sustained release polymers in three different ratios alone and in combination and sunflower oil was used to enable floating property to the beads. The effect of variation in polymer and their concentration was investigated. The beads were evaluated for production yield, particle size, swelling index, density measurement, buoyancy, drug content, drug entrapment efficiency, in vitro release characteristics and release kinetic study. Based on drug entrapment efficiency, buoyancy, swelling and in vitro release, F9 was selected as the optimized formulation. F9 was further subjected to surface morphology by SEM, in vitro release comparison with marketed formulation, in vivo floating study in rabbits and stability study for 90 days. In vitro release follows zero order and fitted in Korsmeyer peppas model (Non-Fickian release). Therefore, the rate of drug release is due to the combined effect of drug diffusion and polymer swelling. The in vivo X-ray studies revealed that the beads were floating in the rabbit stomach up to 10 hours. Thus, it was concluded that the sustained release formulation containing itopride hydrochloride was found to improve patient compliance, minimize the side effects and decrease the frequency of administration.


1986 ◽  
Vol 12 (14) ◽  
pp. 2521-2540 ◽  
Author(s):  
A. Muktadir ◽  
A. Babar ◽  
A. J. Cutie ◽  
F. M. Plakogiannis

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