scholarly journals Refining the in vitro release test method for a dapivirine-releasing vaginal ring to match in vivo performance

2021 ◽  
Author(s):  
Diarmaid J. Murphy ◽  
Deanna Lim ◽  
Ryan Armstrong ◽  
Clare F. McCoy ◽  
Yahya H. Dallal Bashi ◽  
...  
Keyword(s):  
In Vitro Release ◽  
Water Soluble ◽  
Test Method ◽  
Vaginal Ring ◽  
Water Medium ◽  
In Vivo Release ◽  
Release Test ◽  
Vitro Release

AbstractPreviously reported in vitro release test methods for drug-releasing vaginal rings containing poorly water-soluble drugs have described use of water-alcohol systems or surfactant solutions in efforts to maintain sink conditions. Here, as part of efforts to more closely match in vitro and in vivo release for the 25 mg dapivirine matrix-type silicone elastomer vaginal ring for HIV prevention, we have investigated alternatives to the 1:1 v/v water/isopropanol medium described previously. Specifically, we evaluated dapivirine release from rings into (i) monophasic water/isopropanol mixtures of varying compositions and (ii) biphasic buffer/octanol systems using pH 4.2 and pH 7.0 buffers. The rate and mechanism of dapivirine release were dependent upon the isopropanol concentration in the release medium, in accordance with the observed trend in drug solubility. At 0 and 10% v/v isopropanol concentrations, dapivirine release followed a partition-controlled mechansim. For media containing ≥ 20% v/v isopropanol, in vitro release of dapivirine was significantly increased and obeyed permeation-controlled kinetics. Cumulative release of ~3.5 mg dapivirine over 28 days was obtained using a water isopropanol mixture containing 20% v/v isopropanol, similar to the ~4 mg dapivirine released in vivo. Dapivirine release into the biphasic buffer/octanol system (intended to mimic the fluid/tissue environment in vivo) was constrained by the limited solubility of dapivirine in the buffer component in which the ring resided, such that cumulative dapivirine release was consistently lower than that observed with the 20% v/v isopropanol in water medium. Release into the biphasic system was also pH dependent, in line with dapivirine’s pKa and with potential implications for in vivo release and absorption in women with elevated vaginal pH. Graphical abstract

Development and Characterization of Olanzapine Loaded Poly(lactide-co-glycolide) Microspheres for Depot Injection: In vitro and In vivo Release Profiles

2019 ◽  
Vol 16 (4) ◽  
pp. 375-383 ◽  
Author(s):  
Fahad Pervaiz ◽  
Mahmood Ahmad ◽  
Lihong Li ◽  
Ghulam Murtaza
Keyword(s):  
Bulk Density ◽  
Encapsulation Efficiency ◽  
In Vitro Release ◽  
Infrared Spectrometry ◽  
Burst Release ◽  
In Vivo Release ◽  
Depot Injection ◽  
Vitro Release

Purpose: The purpose of this study was to develop a new PLGA based microsphere formulation aimed to release the olanzapine for the period of one month which will result in increased compliance. Methods: Microspheres loaded with olanzapine were prepared using oil in water emulsion and solvent evaporation technique. The microspheres were characterized by surface morphology, shape, size, bulk density, encapsulation efficiency, and Fourier transform infrared spectrometry. In vitro release studies were performed in phosphate buffer at 37°C and in vivo studies were conducted on male Sprague- Dawley rats. Results: The morphological results indicated that microspheres produced were having a smooth surface, spherical shape and the size in the range from 9.71 to 19.90 μm mean diameter. Encapsulation efficiency of olanzapine loaded microspheres was in the range of 78.53 to 96.12% and was affected by changing the ratio of lactic to glycolic acid in copolymer PLGA. The properties of PLGA and other formulation parameters had a significant impact on in vitro and in vivo release of drug from microspheres. In vitro release kinetics revealed that release of drug from microspheres is by both non-Fickian diffusion and erosion of PLGA polymer. In vivo data indicated an initial burst release and then sustained release depending on properties of PLGA, microsphere size, and bulk density. Conclusion: This study indicates that microsphere formulations developed with PLGA (75:25) and PLGA (85:15) have provided a sufficient steady release of drug for at least 30 days and can be potential candidates for 30-day depot injection drug delivery of olanzapine.

In vivo release of bupivacaine from subcutaneously administered oily solution. Comparison with in vitro release

2002 ◽  
Vol 81 (1-2) ◽  
pp. 145-154 ◽  
Author(s):  
Dorrit Bjerg Larsen ◽  
Stig Joergensen ◽  
Niels Vidiendal Olsen ◽  
Steen Honoré Hansen ◽  
Claus Larsen
Keyword(s):  
In Vitro Release ◽  
In Vivo Release ◽  
Vitro Release ◽  
Oily Solution

Comparative Effects of Opiate Agonists Methadone, Levorphanol, and Their Isomers on the Release of Cortical ACh in Vivo and in Vitro

1975 ◽  
Vol 53 (4) ◽  
pp. 540-548 ◽  
Author(s):  
K. Jhamandas ◽  
V. Hron ◽  
M. Sutak
Keyword(s):  
In Vitro Release ◽  
Spontaneous Release ◽  
In Vivo Release ◽  
Small Doses ◽  
Vitro Release ◽  
Cortical Slices

The effect of analgesically active opiate agonists dl-methadone, levorphanol, and their less active forms d-methadone and dextrorphan, respectively, were tested on, (a) the spontaneous release of cortical acetylcholine (ACh) in vivo; (b) the spontaneous and K+-evoked release of cortical ACh in vitro. The injections of dl-methadone, but not d-methadone, inhibited the output of ACh in vivo. Naloxone completely reversed this effect of methadone. Levorphanol in small doses inhibited, and in larger doses stimulated, the in vivo release of ACh. Both effects were antagonized by naloxone. Its dextroisomer dextrorphan was completely inactive. The in vitro release of ACh from cortical slices was inhibited by all four agents. The effects of analgesically active opiates dl-methadone and levorphanol on the in vitro release were not clearly separable from the effects of their inactive forms d-methadone and dextrorphan.

scholarly journals FORMULATION DEVELOPMENT OF COLON TARGETED MESALAMINE PELLETS: IN VITRO-IN VIVO RELEASE STUDY

2019 ◽  
pp. 125-132 ◽  
Author(s):  
JAGAN BAHEKAR ◽  
SHAILESH WADHER
Keyword(s):  
In Vitro Release ◽  
Pharmacokinetic Parameters ◽  
High Dose ◽  
Aminosalicylic Acid ◽  
Formulation Development ◽  
In Vivo Release ◽  
Release Study ◽  
Vitro Release

Objective: This study was intended to investigate the potential of the colon specificity approach comprising of use of pH-sensitive and time-dependent polymers in combination for precise colonic release of Mesalamine or 5-Aminosalicylic acid (5-ASA). Methods: The extrusion and spheronization method, preferably employed in industry for allowing high dose capacity to formulate, was used to prepare drug pellets. The Wurster coating technique used for aqueous coatings of Eudragit NE 40D as an inner coat and Eudragit FS30D as outer coat. The changing pH media used for in vitro release study of optimization batches for both the coating levels. A scanning electron microscope (SEM) was used to evaluate coating thickness and surface morphology. Results: The pharmacokinetic parameters of formulation evaluated by in vivo study in rabbits revealed that the uncoated formulation released the drug too early in the gastrointestinal tract (GIT) with a mean Cmax of 1205.28±0.37 µg/ml at 2 h after administration, whereas desired lag time was achieved in case of coated pellets exhibiting mean Cmax 465.94±0.21 µg/ml and tmax of 8 h. Conclusion: The in vitro and in vivo release study divulge the reliability of approach involving the use of pH sensitivity and time dependency of polymer for drug release in a single formulation for the treatment of colonic diseases. Hence, the present study provides constructive results for colon targeting of 5-ASA pellets with industrially feasible processes.

Reliability of a Single β-Thromboglobulin Measurement in a Diabetic Population : Importance of PGE1 in Anticoagulant Mixture

1987 ◽  
Vol 57 (02) ◽  
pp. 201-204 ◽  
Author(s):  
P Y Scarabin ◽  
L Strain ◽  
C A Ludlam ◽  
J Jones ◽  
E M Kohner
Keyword(s):  
In Vitro Release ◽  
Mean Value ◽  
Reliable Estimate ◽  
Diabetic Patients ◽  
Single Measurement ◽  
Diabetic Population ◽  
The Difference ◽  
Vitro Release

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.

Fenofibrate Solid Dispersion for Improving Oral Bioavailability: Preparation, and Characterization and in vivo Evaluation

2020 ◽  
Vol 13 (5) ◽  
pp. 5102-5109
Author(s):  
Venu Madhav K ◽  
Somnath De ◽  
Chandra Shekar Bonagiri ◽  
Sridhar Babu Gummadi
Keyword(s):  
Oral Bioavailability ◽  
Oral Delivery ◽  
Solid Dispersions ◽  
In Vitro Release ◽  
Aqueous Solubility ◽  
Water Soluble ◽  
Scanning Calorimetry ◽  
In Vivo Evaluation

Fenofibrate (FN) is used in the treatment of hypercholesterolemia. It shows poor dissolution and poor oral bioavailability after oral administration due to high liphophilicity and low aqueous solubility. Hence, solid dispersions (SDs) of FN (FN-SDs) were develop that might enhance the dissolution and subsequently oral bioavailability. FN-SDs were prepared by solvent casting method using different carriers (PEG 4000, PEG 6000, β cyclodextrin and HP β cyclodextrin) in different proportions (0.25%, 0.5%, 0.75% and 1% w/v). FN-SDs were evaluated solubility, assay and in vitro release studies for the optimization of SD formulation. Differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) analysis was performed for crystalline and morphology analysis, respectively. Further, optimized FN-SD formulation evaluated for pharmacokinetic performance in Wistar rats, in vivo in comparison with FN suspension.  From the results, FN-SD3 and FN-SD6 have showed 102.9 ±1.3% and 105.5±3.1% drug release, respectively in 2 h. DSC and PXRD studies revealed that conversion of crystalline to amorphous nature of FN from FT-SD formulation. SEM studies revealed the change in the orientation of FN when incorporated in SDs. The oral bioavailability FN-SD3 and FN-SD6 formulations exhibited 2.5-folds and 3.1-folds improvement when compared to FN suspension as control. Overall, SD of FN could be considered as an alternative dosage form for the enhancement of oral delivery of poorly water-soluble FN.

Development, in vitro and in vivo Evaluations of Solid-Lipid Microparticles based on Solidified Micellar Carrier System for Oral Delivery of Cefepime

2017 ◽  
Vol 10 (1) ◽  
pp. 3582-3593
Author(s):  
Chukwuebuka Umeyor ◽  
Uchechukwu Nnadozie ◽  
Anthony Attama
Keyword(s):  
Oral Delivery ◽  
In Vitro Release ◽  
Carrier System ◽  
Solid Lipid ◽  
Solid Lipid Microparticles ◽  
Release Study ◽  
Lipid Microparticles ◽  
Vitro Release

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.

Formulation and Evaluation of Itopride Hydrochloride Floating Beads for Gastroretentive Delivery

2013 ◽  
Vol 6 (4) ◽  
pp. 2269-2280
Author(s):  
Nagratna Dhople ◽  
P N Dandag ◽  
A P Gadad ◽  
C K Pandey ◽  
Masthiholimath V S
Keyword(s):  
Sustained Release ◽  
In Vitro Release ◽  
Entrapment Efficiency ◽  
Sustained Release Formulation ◽  
Prokinetic Drug ◽  
Drug Entrapment Efficiency ◽  
Itopride Hydrochloride ◽  
Vitro Release

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.

Medicament Release from Ointment Bases: III. Ibuprofen: In Vitro Release and In-Vivo Absorption in Rabbits

1986 ◽  
Vol 12 (14) ◽  
pp. 2521-2540 ◽  
Author(s):  
A. Muktadir ◽  
A. Babar ◽  
A. J. Cutie ◽  
F. M. Plakogiannis
Keyword(s):  
In Vitro Release ◽  
In Vivo Absorption ◽  
Vitro Release
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