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Ocular Drug Delivery Systems
Published in Ambikanandan Misra, Aliasgar Shahiwala, In-Vitro and In-Vivo Tools in Drug Delivery Research for Optimum Clinical Outcomes, 2018
Shubhini A. Saraf, Jovita Kanoujia, Samipta Singh, Shailendra K. Saraf
Ophthalmic solutions (eye drops) are the most popular form for topical administration and lead to good patient compliance, immediate action, and ease of administration. Eye drops contain a drug in dissolved state and are usually adsorbed by the corneal route (cornea, aqueous humor, intraocular tissue), and the conjunctival route (conjunctiva, sclera, choroid, retina, vitreous body). Eye drops (solutions) are capable of treating corneal diseases, iris diseases, and glaucoma (Weijtens et al. 2002; Baudouin et al. 2010). Suspensions are described as a dispersion of an insoluble drug in an aqueous solvent system, containing the appropriate dispersing and suspending agent. They have enhanced residence time at the ocular surface depending upon the drug particle size in suspension (Robinson and Section 1980).
Sustained bimatoprost release using gold nanoparticles laden contact lenses
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Qiong Li, Cheng Ma, Yingpeng Ma, Yiping Ma, Yan Mao, Zelan Meng
In vivo drug release studies were performed in the rabbit model to investigate the amount of bimatoprost released from the conventional soaked contact lens (SM-L, drug loading = 39.8 µg) and selected GNP-laden contact lens (0.3 mM-GN-L, drug loading = 67.7 µg) and compared with 0.03% (w/v) bimatoprost eye drop solution (1 drop = 15 µg, Lumigan® by Allergan) [42]. The contact lenses were placed individually on the right eye of the rabbits (n = 6 for each group) without local anesthesia under the nictitating membrane. One drop of bimatoprost eye drop solution was also instilled in the right eye of the rabbits. The left eye was kept as control in all groups. At predetermined time intervals, the tear fluid (5 µL) samples were collected from the lower conjunctival sac using a disposable glass capillary and preserved at −20 °C until further analysis. The tear fluid samples collected in the Eppendorf tubes were treated with methanol to precipitate the proteins. The sample Eppendorf tubes were centrifuged at 12,000 rpm for 0.5 h and the collected supernatant was analyzed for bimatoprost content using HPLC. The Cmax, tmax, area under the curve, and mean residence time were calculated from the graph of the concentration of bimatoprost in the tear fluid versus time.
Timolol loaded microemulsion laden silicone contact lens to manage glaucoma: in vitro and in vivo studies
Published in Journal of Dispersion Science and Technology, 2021
Ning Wei, Hui Dang, Chao Huang, Yanjuan Sheng
New Zealand rabbits (male and female) were used to investigate the release profiles of timolol in the tear fluid from selected TB-SM-3 (234.3 ± 18.5 μg) and TB-ME-SM-2 (215.3 ± 9.1 μg) contact lenses in comparison to a 0.5% w/v timolol eye drop solution (Lopres, MICROVISION) (1 drop ≈ 50 µl ≈ 250 µg timolol maleate). The sterile timolol-contact lens was placed on the left eye (n = 6) of rabbits (right eye was kept control) without local anesthesia. In the eye drop group, the rabbit’s left eye received single drop of timolol eye drop (right eye was kept control). The rabbit tear fluid was collected using disposable glass capillary from the cul de sac and preserved at -20 °C until analysis. The timolol-tear fluid samples were treated with 1 ml of methanol to precipitate proteins, followed by freeze and centrifugation (Remi freeze-centrifuge) for 1 h at 5000 RPM. The collected supernatant was analyzed for timolol by HPLC method.
Hyaluronic acid and graphene oxide loaded silicon contact lens for corneal epithelial healing
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Chao Huang, Xin Zhang, Yanchun Li, Xiaolan Yang
The in vivo studies were conducted to investigate the HA release in the tear fluid (rabbit model) from the HA-GO-SM-2 and HA-GO-DL-2 contact lenses and compared with the 0.1% w/v HA eye drop solution. The Cmax of HA from the eye drop solution, HA-GO-SM-2 and HA-GO-DL-2 contact lens was found to be 1591.1 ± 521.5 µg, 747.9 ± 367.7 µg and 326.6 ± 249.2 µg, respectively (Figure 3). The high Cmax and rapid decrease in the HA concentration in the eye drop group indicate high clearance of HA from the eye surface due to limitation of eye drop therapy. The HA-GO-SM-2 and HA-GO-DL-2 contact lenses showed high HA retention up to 6 and 48 h, respectively. The HA-GO-DL-2 contact lens showed low burst release and prolong HA retention in comparison to HA-GO-SM-2 batch, which was due to entrapment of HA in the contact lens. The in vitro - in vivo correlation is mandatory to evaluate the performance of the in vitro flux to predict the in vivo release of HA from the contact lens. The linear relationship (See Supplementary material Figure S8) was noted with the contact lenses [HA-GO-SM-2 (R2 = 0.952) and HA-GO-DL-2 (R2 = 0.933)]. To get relief from the dry eye syndrome, the concentration of HA should be greater than 100 µg/ml [41], which can be observed for first 24 h in current study. Thus, the lens can be used as daily disposable lens.