Rheological evaluation of Gelrite® in situ gels for ophthalmic use

Carlfors, Johan; Edsman, Katarina; Petersson, Roger; Jörnving, Katarina

doi:10.1016/s0928-0987(97)00074-2

Cited by 183 publications

(87 citation statements)

References 12 publications

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“…In the presence of a gel structure, G' modulus has to be greater than G" modulus in the frequency range examined and both moduli have to be frequency independent [21,22]. However for blank Na-DOC systems, the viscous property was dominant than the elastic property at the whole frequency range points (G">G').…”

Section: Resultsmentioning

confidence: 99%

Gelation of Sodium-Deoxycholate: Influenced by the Presence of a CorticosteroidBetamethasone-17-Valerate

Homan¹

2017

J. Drug

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This study was designed to evaluate the possible influences of betamethasone-17-valerate (BMV) on the gelation properties of sodium deoxycholate (Na-DOC), due to structural similarities as the monomer and the active agent. For this purpose gel formulations at two different concentrations, 0.05 and 0.1 % (w/w) were prepared and characterized by rheological and thermal analysis. The results indicated that the elastic moduli of the gels increased with increasing concentration of BMV in the system. This phenomenon was shown to be due to the modification of polymerization occurred by interactions between BMV and Na-DOC. The increment of BMV concentration in the formulation, caused a modification of the glass transition temperature (Tg) detected. Tg data pointed out a higher polymerization of Na-DOC with increasing amount of BMV. Transepidermal water loss measurements were also performed to evaluate possible skin irritation. It was observed that the degree of Na-DOC polymerization did not show any irritant effect on the skin.Overall, the results of this study clearly confirmed that incorporation of BMV into Na-DOC gel system produced a synergistic effect on product rheological characteristics, which would be beneficial for topical applications.

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Section: Resultsmentioning

confidence: 99%

Gelation of Sodium-Deoxycholate: Influenced by the Presence of a CorticosteroidBetamethasone-17-Valerate

Homan¹

2017

J. Drug

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“…The viscous (or loss) modulus represents loss of viscous energy and it will be large when the sample is viscous (26). In the presence of a gel structure, G' and G'' are frequency independent whilst for concentrated solutions there is a frequency dependence of G' and G'' (27). A definition of Burchard and Ross-Murphy (28) is that a gel shows a plateau in the real part of the complex modulus extending over an appreciable window of frequencies.…”

Section: Resultsmentioning

confidence: 99%

Development and evaluation of coenzyme Q10 loaded solid lipid nanoparticle hydrogel for enhanced dermal delivery

Korkm¹,

Gökçe²,

Özer³

2013

Acta Pharmaceutica

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Skin is the protective organ of the body with an area around 2 m 2 . The hazardous potential of toxins, pathogens and UV radiation are avoided by the protection that skin supplies (1). UV radiation is the main source of energy that initiates reactive oxygen species (ROS). Formation of ROS leads to oxidative damage in DNA, proteins and lipids. The skin has an enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) and non-enzymatic (antioxidant) protection mechanism against these damages; however, excess ROS production overcomes this protection and causes several diseases such as cancer (2, 3). Hence, effective delivery of an antioxidant into skin in required levels is an important challenge. There are two main steps limiting the effective delivery antioxidants, oxidation of the active substance and carrying the active substance to the viable epidermis.Antioxidants are defined as substances that, when present in a low concentration compared to that of oxidizable substrates, significantly delay or inhibit oxidation of that substance (4). In general, antioxidants act by the chain breaking reaction, by reducing the concentration of reactive oxygen species, by scavenging initiating radicals and by chelating transition metal catalysts (5). Coenzyme Q10 (Q10) is the only lipid soluble endogenous antioxidant. It supports ATP generation during aerobic cellular respiration in the electron transport chain in the mitochondria and inhibits cell membrane peroxidation in reduced form (6, 7). However, it is very difficult to prepare a formulation that helps Q10 delivery to deeper layers of the skin due to the low aqueous solubility of Q10 (log P >10) and due to the barrier function of stratum corneum (8).In the second half of the nineties there was an increasing interest in investigating solid lipid nanoparticles (SLNs) for dermal application. SLNs have many advantages, especially for dermal applications such as occlusion, modulation of drug release and penetration into the skin (9). Since they are made from solid lipids, chemically unstable lipid soluble compounds that are sensitive to oxidation can be successfully encapsulated in the SLNs (8, 10). Several molecules were incorporated into lipid nanoparticles, e.g., ascorbyl palmitate, resveratrol, retinol and retinyl palmitate, vitamin E and vitamin E acetate (8,(11)(12)(13)(14). It has been shown that systemic uptake of active substances (e.g., isotretinoin) through skins could be avoided and SLN could increase the accumulative uptake of the active material in the skin (15). SLNs are produced as liquid dispersions and their incorporation into hydrogels or emulsions helps enhance the retention time in the applied area and patient compliance (16,17).Hydrogels are generally formed from carbomers that have the ability to absorb water, get hydrated and swell by neutralization with a base. Carbomers have been mainly used in liquid or semi-solid pharmaceutical formulations in order to modify their flow characteristics (17,18).The aim of this work was to carry an effic...

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“…The rheology of ion triggered in situ gelling systems based on gelrite ® for ocular drug delivery has been studied by Carlfors et al [42]. The study suggested that rapid gelation in the eye is necessary for successful application of in situ gelling systems.…”

Section: Poly (N-isopropylacrylamide)mentioning

confidence: 99%

“…Interestingly the gels were much better retained in the human eyes as compared to that of rabbit's eyes. The ocular residence time of gels is depend on the rheological properties and viscosity [21,22,42]. The gels showed high elasticity, which was concentration independent at 0.6% gelrite ® and above, suggesting longer precorneal contact times.…”

Section: Poly (N-isopropylacrylamide)mentioning

confidence: 99%

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Newer Trends in In Situ Gelling Systems for Controlled Ocular Drug Delivery

Jain¹,

Kumar²,

Singh³

et al. 2016

JAPLR

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In situ -gelling systems has the great potential in the wide areas of drug delivery. The application areas of such systems are broad and these systems can be formulated not only as gels but also as in situ gelling nanospheres, microspheres and liposomes. To overcome the drawbacks associated with conventional drug delivery systems and take advantages of both solutions and gels, such as accurate dosing, ease of administration of the former and longer precorneal residence of the latter, a newer concept of in situ gelling drug delivery systems was came in light for the first time in the early 1980s. In situ gelling systems are the polymeric solutions which can be administered in solution form and immediately undergoes sol-gel phase transition in to a viscoelastic gel upon exposure to physiological conditions (e.g. pH, temperature and ionic concentration) or application of external triggers. In situ gelling systems seems to have wide applications in ocular therapy. A lot of research is going on in this area proves the fact that in situ gelling systems can be advantageous in the ocular drug delivery. In the present review we will discuss recent researches involving application of in situ gelling polymers, their applications in the various domains of drug delivery and marketed formulations based on in situ gelling systems.

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Rheological evaluation of Gelrite® in situ gels for ophthalmic use

Cited by 183 publications

References 12 publications

Gelation of Sodium-Deoxycholate: Influenced by the Presence of a CorticosteroidBetamethasone-17-Valerate

Gelation of Sodium-Deoxycholate: Influenced by the Presence of a CorticosteroidBetamethasone-17-Valerate

Development and evaluation of coenzyme Q10 loaded solid lipid nanoparticle hydrogel for enhanced dermal delivery

Newer Trends in In Situ Gelling Systems for Controlled Ocular Drug Delivery

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