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Nihar Ranjan Pani - One of the best experts on this subject based on the ideXlab platform.
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optimization of hpmc and Carbopol concentrations in non effervescent floating tablet through factorial design
Carbohydrate Polymers, 2014Co-Authors: Sujata Acharya, Sradhanjali Patra, Nihar Ranjan PaniAbstract:Abstract This study was to optimize HPMC K4M and Carbopol 934 concentration in the development of non-effervescent floating tablets (NEFTs) of glipizide as model drug using 3 2 factorial design. The time required for releasing drug of 50% and 80% and similarity factor were the target responses. HPMC K4M and Carbopol 934 concentrations were the variables. The response surface methodology and optimized polynomial equations were used to select the optimal formulation with desired responses. The excipients used in tablets were compatible with glipizide as per the results of isothermal stress testing and DSC study. The drug release of entire NEFTs followed zero order kinetics and non-Fickian diffusion mechanism. Validation of the optimization technique demonstrated the reliability of the model. The optimized formulation containing 124.33 mg HPMC K4M and 25.76 mg Carbopol 934 was prepared according to the software determined levels. The stability study of the optimized formulation proved the integrity of the developed formulation.
Sujata Acharya - One of the best experts on this subject based on the ideXlab platform.
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optimization of hpmc and Carbopol concentrations in non effervescent floating tablet through factorial design
Carbohydrate Polymers, 2014Co-Authors: Sujata Acharya, Sradhanjali Patra, Nihar Ranjan PaniAbstract:Abstract This study was to optimize HPMC K4M and Carbopol 934 concentration in the development of non-effervescent floating tablets (NEFTs) of glipizide as model drug using 3 2 factorial design. The time required for releasing drug of 50% and 80% and similarity factor were the target responses. HPMC K4M and Carbopol 934 concentrations were the variables. The response surface methodology and optimized polynomial equations were used to select the optimal formulation with desired responses. The excipients used in tablets were compatible with glipizide as per the results of isothermal stress testing and DSC study. The drug release of entire NEFTs followed zero order kinetics and non-Fickian diffusion mechanism. Validation of the optimization technique demonstrated the reliability of the model. The optimized formulation containing 124.33 mg HPMC K4M and 25.76 mg Carbopol 934 was prepared according to the software determined levels. The stability study of the optimized formulation proved the integrity of the developed formulation.
Adnan Al-marzoqi - One of the best experts on this subject based on the ideXlab platform.
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Influence of various concentrations of terpene-4-ol enhancer and Carbopol-934 mucoadhesive upon the in vitro ocular transport and the in vivo intraocular pressure lowering effects of dorzolamide ophthalmic formulations using albino rabbits
Journal of pharmaceutical sciences, 2010Co-Authors: Mohsen I. Afouna, Alaa Khedr, Ashraf B. Abdel-naim, Adnan Al-marzoqiAbstract:The objectives of the current study are (i) to maximize the ocular bioavailability of dorzolamide hydrochloride (DZD) through; (a) enhancement of the DZD corneal transport using various concentrations of selected natural terpene-4-ol enhancers, (b) increasing the contact time of the drug with the absorbing tissues of the eye using selected Carbopol-934 (C-934) as mucoadhesive to reduce the extensive pre-corneal loss of the installed dose due to the physiologically normal fast tear-washout, and (ii) to assess the in vivo intraocular pressure (IOP) lowering effects of the gel test formulations using normotensive New Zealand albino rabbits. In this study, DZD was formulated as 2% formulations ophthalmic gels containing different concentrations of C-934 as mucoadhesive, as well as, with various concentrations of terpene-4-ol as a natural corneal penetration enhancers. The transport of DZD from the gel formulations was quantitatively determined using in vitro diffusion experiments. The permeability parameters of DZD were calculated employing the most appropriate mathematical equations. Further, the in vivo IOP lowering effects of the test formulations were also assessed using the TONO-PEN®XL applanation tonometer in normotensive New Zealand albino rabbits. The overall results revealed that there is a direct correlation between both the in vitro permeability parameters and the contact period with the ocular tissues and the in vivo ΔIOP. In such case, the in vitro permeability parameters of DZD could be used as a determinant for the in vivo IOP measurements. The magnitude of the DZD-IOP lowering effects as well as the durations of actions for the test formulations has been found to be greatly dependent upon (a) the concentration of the terpene-4-ol corneal penetration enhancer and (b) the duration of contact period with the ocular tissues, which was found to be a single-valued function of the C-943 mucoadhesive concentration. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:119–127, 2010
Yanhong Shang - One of the best experts on this subject based on the ideXlab platform.
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effects of Carbopol 934 proportion on nanoemulsion gel for topical and transdermal drug delivery a skin permeation study
International Journal of Nanomedicine, 2016Co-Authors: Yin Zheng, Wuqing Ouyang, Yunpeng Wei, Shahid Faraz Syed, Chaoshuang Hao, Bozhen Wang, Yanhong ShangAbstract:Nanoemulsions (NEs) are used as transdermal drug delivery systems for systematic therapeutic purposes. We hypothesized that the skin permeation profile of an NE could be modulated by incorporating it into a hydrogel containing differing proportions of thickening agent. The objectives of this study were as follows: 1) to determine the stability and skin irritability of NE gels (NGs) containing 1%, 2%, and 3% (w/w) Carbopol® 934 (CP934) (termed NG1, NG2, and NG3, respectively); 2) to compare the skin permeation profiles and drug deposition patterns of the NGs; and 3) to visualize the drug delivery routes of the NGs. Terbinafine and citral were incorporated into the NGs as model drugs. Ex vivo skin permeation tests indicated that the percutaneous flux rates of terbinafine decreased in the order NE (215 μg/cm2) > NG1 (213 μg/cm2) > NG2 (123 μg/cm2) > NG3 (74.3 μg/cm2). The flux rates of citral decreased in the order NE (1,026 μg/cm2) > NG1 (1,021 μg/cm2) > NG2 (541 μg/cm2) > NG3 (353 μg/cm2). The NGs accumulated greater amounts of the drugs in the stratum corneum and less in the epidermis/dermis than did the NE (P<0.05) over a period of 12 h. Laser scanning confocal microscopy indicated that the NGs altered the main drug delivery routes from skin appendages to intercellular paths. Histological images suggested that perturbations to the skin structure, specifically the size of the epidermal intercellular spaces and the separation distance of dermal collagen bundles, could be significantly minimized by increasing the proportion of CP934. These results suggest that adjustments of the CP934 proportions can be used to modulate the skin permeation profiles of NGs for specific therapeutic purposes.
Angel Concheiro - One of the best experts on this subject based on the ideXlab platform.
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poly acrylic acid microgels Carbopol 934 surfactant interactions in aqueous media part i nonionic surfactants
International Journal of Pharmaceutics, 2003Co-Authors: Rafael Barreiroiglesias, Carmen Alvarezlorenzo, Angel ConcheiroAbstract:Abstract The interaction of sodium dodecylsulfate (SDS) or benzalkonium chloride (BkCl) with Carbopol microgels (0.25% (w/w)) in water was studied through pH, trasmittance, viscosity, surface tension, conductivity, fluorescence, oil solubilization, and microcalorimetry measurements. In the case of the anionic surfactant, enthalpy-driven hydrophobic absorption of SDS into Carbopol microgels began when SDS concentration reached 0.05–0.08% and ended around 0.6%. These concentrations were estimated as the critical aggregation (cac) and saturation binding concentration, respectively. The hydrophobic absorption of the surfactant accompanied by its counter-ion caused Carbopol microgels to swell and promoted the occurrence of bridges among several Carbopol microgels. As a consequence, the consistency of the dispersions increased significantly. Above binding saturation, further addition of SDS produced a shielding effect among the anionic charges of Carbopol and its dehydration, which was shown as a decrease in the viscosity of the dispersions. At low shear rates, the dispersions behaved as pseudoplastic owing to orientation of Carbopol/SDS aggregates in the flow direction. Increasing shear rates caused the inter-microgel bridges to break, the water layer surrounding them to diminish, and the system to show a shear-thickening behavior. In contrast, Carbopol/BkCl aggregates showed shear-thickening flow in the whole range of shear rates analyzed. Electrostatic interactions between BkCl and Carbopol carboxylic groups release protons to the medium and decrease the internal osmotic pressure of the microgels. This may favor the establishment of hydrophobic interactions among surfactant tails, and induces Carbopol microgels to collapse. The cac was approximately 0.01% BkCl. Saturation binding occurred at 0.3–0.5%, indicating that only 25–40 mol% carboxylic groups were neutralized with BkCl. The shrinking of Carbopol microgels as BkCl is absorbed prevents additional surfactant molecules from interacting with the remaining carboxylic groups. Microcalorimetry assays revealed that the aggregation process occurred with a strong gain in enthalpy.
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extrusion spheronization of blends of Carbopol 934 and microcrystalline cellulose
Drug Development and Industrial Pharmacy, 2001Co-Authors: A Gomezcarracedo, Carmen Alvarezlorenzo, J L Gomezamoza, R Martinezpacheco, Consuelo Souto, Angel ConcheiroAbstract:We evaluated the effects of several process variables on the pharmaceutical and drug release properties of extrusion-spheronization pellets of blends of Carbopol 934 and microcrystalline cellulose (MCC) containing a high proportion of Carbopol. The model drug was theophylline. Rheological monitoring during mixing was by mixer torque rheometry. Carbopol:MCC blends wetted with a CaCl2 solution showed different rheological behavior compared to blends with a high proportion of MCC wetted with water only. In contrast to previous suggestions, the optimal wetting point for extrusion did not coincide with the point of peak torque, but occurred just beyond this point, at much lower torque. The influence of process variables on blend properties was investigated with a three-variable factorial design (Carbopol:MCC ratio, wetting liquid proportion, CaCl2 :Carbopol ratio), and the influence of process variables on pellet properties with a four-variable design (the variables listed plus extrusion screen hole diameter)....