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Studies on In situ Hydrogel: A Smart Way for Safe and Sustained Ocular Drug Delivery.

Shastri D, Patel L, Parikh R - J Young Pharm (2010)

Bottom Line: So, to reduce this concentration, an attempt was made to combine the PF127 with other polymers like hydroxy propyl methyl cellulose (HPMC) as a viscosity increasing agent or with polymers like carbopol 940, xanthan gum, and sodium alginate (high glucuronic acid content) showing a pH and cation-triggered sol-gel transition, respectively.The formulations were optimized by the viscosity measurement and in vitro gelation study.Finally, we concluded that by using this type of combination system, we could reduce not only the concentration of individual polymers but also the side effects without compromising the in vitro gelling capacity as well as overall rheology of the system.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutics, K.B. Institute of Pharmaceutical Education & Research, Sector 23, Gandhinagar, Gujarat-382 023, India.

ABSTRACT
The present work describes the formulation development of ophthalmic in situ gelling system using thermo-reversible gelling polymer, i.e. Pluronic F 127 (PF127). Because of high concentration (20 to 25%w/v) of this polymer required for in situ gelation causes irritation to the eye. So, to reduce this concentration, an attempt was made to combine the PF127 with other polymers like hydroxy propyl methyl cellulose (HPMC) as a viscosity increasing agent or with polymers like carbopol 940, xanthan gum, and sodium alginate (high glucuronic acid content) showing a pH and cation-triggered sol-gel transition, respectively. Different batches were prepared of varying concentrations of these polymers with PF127 using cromolyn sodium 2%w/v in phosphate buffer pH 5.0. The formulations were optimized by the viscosity measurement and in vitro gelation study. Selected formulations were evaluated for in vitro drug release profile and indicated sustain drug release over a period of 10 h. Effect of sterilization on drug content, pH, clarity, and viscosity were also evaluated. Finally, we concluded that by using this type of combination system, we could reduce not only the concentration of individual polymers but also the side effects without compromising the in vitro gelling capacity as well as overall rheology of the system.

No MeSH data available.


Comparative rheological profile of the selected formulations at pH 5.0 and 25°C
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Figure 0001: Comparative rheological profile of the selected formulations at pH 5.0 and 25°C

Mentions: The selected formulations (pH 5.0) at 25°C were poured into the sample adaptor of the Brookfield viscometer (LVT model) and the angular velocity was increased gradually from 0.3 to 30 rpm. The hierarchy of the angular velocity was reversed and average dial reading was considered to calculate the viscosity. Same formulations were again evaluated for viscosity in a similar fashion after adjusting their temperature to 37 °C and pH to 7.4 by adding 0.5M NaOH. The temperature was maintained within ±1.0 °C by a recirculating bath connected to the sample cup of the viscometer. The samples were equilibrated on the plate for 5 min to reach the running temperature before each measurement. The viscosity measured at both the conditions for selected formulations were plotted versus the angular velocity (rpm). Comparative rheological profiles were shown for all three formulations together in Figures 1 and 2. All the measurements were taken in triplicate.


Studies on In situ Hydrogel: A Smart Way for Safe and Sustained Ocular Drug Delivery.

Shastri D, Patel L, Parikh R - J Young Pharm (2010)

Comparative rheological profile of the selected formulations at pH 5.0 and 25°C
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3021684&req=5

Figure 0001: Comparative rheological profile of the selected formulations at pH 5.0 and 25°C
Mentions: The selected formulations (pH 5.0) at 25°C were poured into the sample adaptor of the Brookfield viscometer (LVT model) and the angular velocity was increased gradually from 0.3 to 30 rpm. The hierarchy of the angular velocity was reversed and average dial reading was considered to calculate the viscosity. Same formulations were again evaluated for viscosity in a similar fashion after adjusting their temperature to 37 °C and pH to 7.4 by adding 0.5M NaOH. The temperature was maintained within ±1.0 °C by a recirculating bath connected to the sample cup of the viscometer. The samples were equilibrated on the plate for 5 min to reach the running temperature before each measurement. The viscosity measured at both the conditions for selected formulations were plotted versus the angular velocity (rpm). Comparative rheological profiles were shown for all three formulations together in Figures 1 and 2. All the measurements were taken in triplicate.

Bottom Line: So, to reduce this concentration, an attempt was made to combine the PF127 with other polymers like hydroxy propyl methyl cellulose (HPMC) as a viscosity increasing agent or with polymers like carbopol 940, xanthan gum, and sodium alginate (high glucuronic acid content) showing a pH and cation-triggered sol-gel transition, respectively.The formulations were optimized by the viscosity measurement and in vitro gelation study.Finally, we concluded that by using this type of combination system, we could reduce not only the concentration of individual polymers but also the side effects without compromising the in vitro gelling capacity as well as overall rheology of the system.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutics, K.B. Institute of Pharmaceutical Education & Research, Sector 23, Gandhinagar, Gujarat-382 023, India.

ABSTRACT
The present work describes the formulation development of ophthalmic in situ gelling system using thermo-reversible gelling polymer, i.e. Pluronic F 127 (PF127). Because of high concentration (20 to 25%w/v) of this polymer required for in situ gelation causes irritation to the eye. So, to reduce this concentration, an attempt was made to combine the PF127 with other polymers like hydroxy propyl methyl cellulose (HPMC) as a viscosity increasing agent or with polymers like carbopol 940, xanthan gum, and sodium alginate (high glucuronic acid content) showing a pH and cation-triggered sol-gel transition, respectively. Different batches were prepared of varying concentrations of these polymers with PF127 using cromolyn sodium 2%w/v in phosphate buffer pH 5.0. The formulations were optimized by the viscosity measurement and in vitro gelation study. Selected formulations were evaluated for in vitro drug release profile and indicated sustain drug release over a period of 10 h. Effect of sterilization on drug content, pH, clarity, and viscosity were also evaluated. Finally, we concluded that by using this type of combination system, we could reduce not only the concentration of individual polymers but also the side effects without compromising the in vitro gelling capacity as well as overall rheology of the system.

No MeSH data available.