An Overview: The Evaluation of Formation Mechanisms, Preparation Techniques and Chemical and Analytical Characterization Methods of the In Situ Forming Implants

2020 ◽  
Vol 16 ◽  
Author(s):  
Muge Kilicarslan ◽  
Ayse Nur Buke
Keyword(s):  
New Technologies ◽  
In Vitro Dissolution ◽  
Formation Mechanisms ◽  
Liquid Form ◽  
Characterization Methods ◽  
Advantages And Disadvantages ◽  
In Situ Forming

: One of the major developments of the last decade is the preparation of in situ forming implant formulations. Injectable, biocompatible and/or biodegradable polymer based in situ implants are classified differently due to implant formation based on in vivo solid depot or formation mechanisms inducing liquid form, gel or solid depot. In this review, published studies to date regarding in situ forming implant systems were compiled and their formation mechanisms, materials and methods used, routes of administration, chemical and analytical characterizations, quality control tests and in vitro dissolution tests were compared in Tables and they were evaluated. There are several advantages and disadvantages of these dosage forms due to the formation mechanism, polymer and solvent type and the ratio used in formulations and all of these parameters were discussed separately. In addition, new generation systems developed to overcome the difficulties encountered in in situ implants have been evaluated. There are, some approved products of in situ implant preparations that can be used for different indications are available on the market and the clinical phase studies nowadays. In vitro and in vivo data obtained by the analysis of the application of new technologies in many studies evaluated in this review showed that the number of approved drugs to be used for various indications with different drugs would increase in the future.

In Vitro and In Vivo Drug Release from a Novel In Situ Forming Drug Delivery System

2007 ◽  
Vol 25 (6) ◽  
pp. 1347-1354 ◽  
Author(s):  
Heiko Kranz ◽  
Erol Yilmaz ◽  
Gayle A. Brazeau ◽  
Roland Bodmeier
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Drug Delivery System ◽  
Delivery System ◽  
In Situ Forming

In-vitro, ex-vivo, and in-vivo release evaluation of in situ forming buprenorphine implants using mixture of PLGA copolymers and additives

2018 ◽  
Vol 68 (16) ◽  
pp. 965-977 ◽  
Author(s):  
Hossein Kamali ◽  
Elham Khodaverdi ◽  
Farzin Hadizadeh ◽  
Seyed Ahmad Mohajeri ◽  
Younes Kamali ◽  
...  
Keyword(s):  
Ex Vivo ◽  
In Situ Forming ◽  
In Vivo Release

The Role of Microbiology in Models of Dental Caries: Reaction Paper

1995 ◽  
Vol 9 (3) ◽  
pp. 255-269 ◽  
Author(s):  
G.H. Bowden
Keyword(s):  
Process Selection ◽  
Advantages And Disadvantages ◽  
Test Models ◽  
Plaque Development ◽  
In Vitro Systems ◽  
Selection Of

Models of the caries process have made significant contributions toward defining the roles of bacteria in caries. Microbiologists use a variety of in vitro systems to model aspects of the caries process. Also, in situ models in humans provide information on the microbiology of caries in vivo. These models do not involve the entire process leading to natural caries; consequently, the results from such studies are used to deduce the roles of bacteria in natural caries. Therefore, they can be described as Inferential Caries Models. In contrast, animal models and some clinical trials in humans involve natural caries and can be described as Complete Caries Models. Furthermore, these models are used in two distinct ways. They can be used as Exploratory Models to explore different aspects of the caries process, or as Test Models to determine the effects of anticaries agents. This dichotomy in approach to the use of caries models results in modification of the models to suit a particular role. For example, if we consider Exploratory Models, the in situ appliance in humans is superior to others for analyzing the microbiology of plaque development and demineralization in vivo. The chemostat and biofilm models are excellent for exploring factors influencing bacterial interactions. Both models can also be used as Test Models. The in situ model has been used to test the effects of fluoride on the microflora and demineralization, while the chemostat and biofilm models allow for the testing of antibacterial agents. Each model has its advantages and disadvantages and role in analysis of the caries process. Selection of the model depends on the scientific question posed and the limitations imposed by the conditions available for the study.

scholarly journals Tripling the Bioavailability of Rosuvastatin Calcium Through Development and Optimization of an In-Situ Forming Nanovesicular System

Pharmaceutics ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 275 ◽  
Author(s):  
Ibrahim Elsayed ◽  
Rania Moataz El-Dahmy ◽  
Ahmed Hassen Elshafeey ◽  
Nabaweya Abdelaziz Abd El Gawad ◽  
Omaima Naim El Gazayerly
Keyword(s):  
Dissolution Rate ◽  
Oral Bioavailability ◽  
Entrapment Efficiency ◽  
In Situ Forming ◽  
Market Product ◽  
Simple Step ◽  
Rosuvastatin Calcium

In situ forming nanovesicular systems (IFNs) were prepared and optimized to improve Rosuvastatin calcium (RC) oral bioavailability through increasing its solubility and dissolution rate. The IFN was composed of Tween® 80 (T80), cetyl alcohol (CA), in addition to mannitol or Aerosil 200. A single simple step was adopted for preparation, then the prepared formulations were investigated by analyzing their particle size (PS), polydispersity index (PDI), Zeta potential (ZP), entrapment efficiency (EE), and flowability properties. D-optimal design was applied to choose the optimized formulations. The maximum desirability values were 0.754 and 0.478 for the optimized formulations containing 0.05 g CA, 0.18 g T80, and 0.5 g mannitol (OFM) or Aerosil (OFA), respectively. In vitro drug release from the optimized formulations showed a significantly faster dissolution rate when compared to the market product. In vivo performance of the optimized formulations in rabbits was investigated after filling them into enteric-coated capsules. Ultimately, OFA formulation achieved a 3 times increase in RC oral bioavailability in comparison with the market product, supporting the hypothesis of considering IFNs as promising nanocarriers able to boost the bioavailability of BCS class II drugs.

scholarly journals In vivo imaging of in situ motility of fresh and liquid stored ram spermatozoa in the ewe genital tract

Reproduction ◽  
2009 ◽  
Vol 138 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Xavier Druart ◽  
Juliette Cognié ◽  
Gérard Baril ◽  
Frédérique Clément ◽  
Jean-Louis Dacheux ◽  
...  
Keyword(s):  
Genital Tract ◽  
Liquid Form ◽  
Video Images ◽  
Liquid Storage ◽  
Straight Line ◽  
Intra Uterine Insemination

The fertility of ram semen after cervical insemination is substantially reduced by 24 h of storage in liquid form. The effects of liquid storage on the transit of ram spermatozoa in the ewe genital tract was investigated using a new procedure allowing direct observation of the spermatozoa in the genital tract. Ejaculated ram spermatozoa were double labeled with R18 and MitoTracker Green FM, and used to inseminate ewes in estrus either cervically through the vagina or laparoscopically into the base of the uterine horns. Four hours after insemination, the spermatozoa were directly observedin situusing fibered confocal fluorescence microscopy in the base, middle and tip of the uterine horns, the utero-tubal junction (UTJ) and the oviduct. The high resolution video images obtained with this technique allowed determination of the distribution of spermatozoa and individual motility in the lumen of the ewe's genital tract. The results showed a gradient of increasing concentration of spermatozoa from the base of the uterus to the UTJ 4 h after intra-uterine insemination into the base of the horns. The UTJ was shown to be a storage region for spermatozoa before their transfer to the oviduct. Thein vitrostorage of spermatozoa in liquid form decreased their migration through the cervix and reduced the proportion of motile spermatozoa and their straight line velocity at the UTJ and their transit into the oviduct.

scholarly journals In Vitro Evaluation of Poly(lactide-co-glycolide) In Situ Forming Gels for Bedaquiline Fumarate Salt and Pharmacokinetics Following Subcutaneous Injection in Rats

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1231
Author(s):  
Sandy Van Hemelryck ◽  
Rani Wens ◽  
Hannelore van Poppel ◽  
Milou Luijks ◽  
Koosha Shahidi ◽  
...  
Keyword(s):  
Drug Release ◽  
Point Of View ◽  
Solvent Ratio ◽  
Sustained Drug Release ◽  
Polyethylene Glycol 400 ◽  
In Situ Forming ◽  
Fumarate Salt

This study evaluated in vitro and in vivo drug release of bedaquiline from in situ forming gels (ISGs) containing 200 mg eq./g bedaquiline fumarate salt prepared with four different grades of poly(d,l-lactide) (PDLLA) or poly(d,l-lactide-co-glycolide) (PLGA) with a lactide/glycolide ratio of 50/50 or 75/25 and acid (A) or ester (E) end-capping in N-methyl-2-pyrrolidone at a polymer/solvent ratio of 20/80% (w/w). Mean in vitro drug release in 0.05 M phosphate buffer pH 7.4 with 1% (w/v) sodium lauryl sulphate was 37.3, 47.1, 53.3, and 62.3% within 28 days for ISGs containing PLGA5050A, PDLLA, PLGA7525A, and PLGA7525E, respectively. The data suggested that drug release was primarily controlled by precipitated drug redissolving, rather than polymer erosion. In vivo pharmacokinetic profiles after subcutaneous injections in rats were comparable for all ISGs (mean half-lives (t1/2) ranged from 1411 to 1695 h) and indicated a sustained drug release when compared to a solution of bedaquiline fumarate salt in polyethylene glycol 400/water 50/50% (v/v) (mean t1/2 of 895 h). In conclusion, PLGA or PDLLA-based ISGs have shown potential for parenteral sustained delivery of bedaquiline, suggesting further preclinical and clinical studies. From a formulation point of view, this case example highlights the importance of the interplay between drug solubility in biological media and dissolution of drug precipitates, which, in addition to the incorporation of diffusion controlling polymers, governs the release of the active drug.

scholarly journals In Situ-Forming Cellulose/Albumin-Based Injectable Hydrogels for Localized Antitumor Therapy

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4221
Author(s):  
Ying Chen ◽  
Xiaomin Wang ◽  
Yudong Huang ◽  
Peipei Kuang ◽  
Yushu Wang ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Antitumor Therapy ◽  
Injectable Hydrogels ◽  
External Temperature ◽  
Minimal Invasiveness ◽  
In Situ Forming ◽  
External Stimuli

Injectable hydrogels, which are formed in situ by changing the external stimuli, have the unique characteristics of easy handling and minimal invasiveness, thus providing the advantage of bypass surgical operation and improving patient compliance. Using external temperature stimuli to realize the sol-to-gel transition when preparing injectable hydrogel is essential since the temperature is stable in vivo and controllable during ex vivo, although the hydrogels obtained possibly have low mechanical strength and stability. In this work, we designed an in situ fast-forming injectable cellulose/albumin-based hydrogel (HPC-g-AA/BSA hydrogels) that responded to body temperature and which was a well-stabilized hydrogen-bonding network, effectively solving the problem of poor mechanical properties. The application of localized delivery of chemotherapeutic drugs of HPC-g-AA/BSA hydrogels was evaluated. In vitro and in vivo results show that HPC-g-AA/BSA hydrogels exhibited higher antitumor efficacy of reducing tumor size and seem ideal for localized antitumor therapy.

scholarly journals In-vitro/In-vivo comparison of leuprolide acetate release from an in-situ forming plga system

2013 ◽  
Vol 21 (1) ◽  
Author(s):  
Roya Mashayekhi ◽  
Hamid Mobedi ◽  
Jamal Najafi ◽  
Marjan Enayati
Keyword(s):  
Leuprolide Acetate ◽  
In Situ Forming
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