Influence of magnesium aluminium silicate on rheological, release and permeation characteristics of diclofenac sodium aqueous gels in-vitro

Priprem, Aroonsri; Puttipipatkhachorn, Satit

doi:10.1211/0022357055795

Cited by 23 publications

(12 citation statements)

References 15 publications

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“…This indicated that not only the diffusion process of carbamazepine but also the swelling of the polymers controlled the release of carbamazepine from the gel. The results were in agreement with the release of diclofenac sodium from gel prepared using poloxamer 407 and hypromellose (Pongjanyakul et al 2005). The time taken for release of 50% of the drug (t50%) was 48 min.…”

Section: In-vitro Release Of Carbamazepinesupporting

confidence: 83%

Carbamazepine uptake into rat brain following intra-olfactory transport

Barakat

Omar

Ahmed

2006

Journal of Pharmacy and Pharmacology

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Targeting the brain via nasal administration of drugs has been studied frequently over the last few years. In this study, a suitable gel formulation was designed to provide the absorption of a highly lipophilic drug through nasal mucosa. For this purpose, carbamazepine was chosen as the model drug. Hypromellose and Carbopol were used as mucoadhesive polymers in the formulation to increase the residence time of the gel on the mucosa. The objective of this study was to confirm the existence of a transport pathway for a drug (carbamazepine) to the brain directly from the nasal cavity, by comparing the concentration of drug in the brain after intranasal (i.n.), intravenous (i.v.), and oral (p.o.) administration. A statistically significant high level of the drug was found in the brain following intranasal administration compared with the intravenous and oral routes. These findings suggested the existence of a direct transport pathway for carbamazepine from the nasal cavity to the brain. This pathway may represent a new delivery route to the brain and central nervous system of such drugs which are needed in high and rapid concentration in the brain, especially in emergencies.

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Section: In-vitro Release Of Carbamazepinesupporting

confidence: 83%

Carbamazepine uptake into rat brain following intra-olfactory transport

Barakat

Omar

Ahmed

2006

Journal of Pharmacy and Pharmacology

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“…The MAS dispersion possessed a basic pH, and its zeta potential was found to be −44.7 mV (Table I). The addition of MAS into the polymer dispersions caused an obvious increase in the pH because of a mild alkalinity of OH groups associated with Si, Mg, and Al in MAS (11). The basic pH of the composite dispersions suggested that SCMC, SA, and MAS also presented negatively charged molecules.…”

Section: Characterization Of Polymer-mas Dispersionsmentioning

confidence: 99%

“…Therefore, MAS has been widely used as a pharmaceutical suspending and stabilizing agent (4). In addition, the positively charged edges on the layers of MAS could interact with anionic polymers such as xanthan gum (9), carbomer (10), and sodium alginate (SA) (11,12), resulting in viscosity synergism and an increase in the thixotropic properties of polymeric dispersions. To obtain similar results, MAS was also used in combination with sodium carboxymethylcellulose (SCMC) for improving not only physical stability (13) but also the flow behavior of suspensions (3).…”

Section: Introductionmentioning

confidence: 99%

Polymer–Magnesium Aluminum Silicate Composite Dispersions for Improved Physical Stability of Acetaminophen Suspensions

Puttipipatkhachorn

2009

AAPS PharmSciTech

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Abstract. The aims of this study were to characterize the morphology and size of flocculates and the zeta potential and rheological properties of polymer-magnesium aluminum silicate (MAS) composite dispersions and to investigate the physical properties of acetaminophen (ACT) suspensions prepared using the composite dispersions as a flocculating/suspending agent. The polymers used were sodium alginate (SA), sodium carboxymethylcellulose (SCMC), and methylcellulose (MC). The results showed that SA, SCMC, and MC could induce flocculation of MAS by a polymer-bridging mechanism, leading to the changes in the zeta potential of MAS and the flow properties of the polymer dispersions. The microscopic morphology and size of the flocculates was dependent on the molecular structure of the polymer, especially ether groups on the polymer side chain. The residual MAS from the flocculation could create a three-dimensional structure in the SA-MAS and SCMC-MAS dispersions, which brought about not only an enhancement of viscosity and thixotropic properties but also an improvement in the ACT flocculating efficiency of polymers. The use of polymer-MAS dispersions provided a higher degree of flocculation and a lower redispersibility value of ACT suspensions compared with the pure polymer dispersions. This led to a low tendency for caking of the suspensions. The SCMC-MAS dispersions provided the highest ACT flocculating efficiency, whereas the lowest ACT flocculating efficiency was found in the MC-MAS dispersions. Moreover, the added MAS did not affect ACT dissolution from the suspensions in an acidic medium. These findings suggest that the polymer-MAS dispersions show good potential for use as a flocculating/suspending agent for improving the rheological properties and physical stability of the suspensions.KEY WORDS: magnesium aluminum silicate; physical stability; sodium alginate; sodium carboxymethylcellose; suspensions.

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“…Upon hydration, its weakly positive edges are attracted by the negatively charged faces, such that the attraction of face-to-edge creates a three-dimensional structure and charges on the layers of MAS will interact with anionic polymers [28,29], resulting in a viscosity synergism. In a recent study [30,31], MAS was used to improve the rheological properties of NaAlg gel. We realize that NaAlg with MAS particles can form a microcomposite film with improved mechanical properties to retard the water uptake as well as drug permeability.…”

Section: Introductionmentioning

confidence: 99%