Formulation and Characterization of pH Induced in situ Gels Containing Sulfacetamide Sodium for Ocular Drug Delivery: A Combination of Carbopol®/ HPMC Polymer

Abstract

Introduction: Topical delivery of eye drops which currently accounts to 90% of available ocular dosage forms are ideal for the treatment of eye diseases but having limitations of poor therapeutic response and low bioavailability. Objectives: The objectives of present research was to develop and characterize sustained release in situ ocular gels containing sufacetamide sodium using pH induced gelling polymers for improved therapeutic response and patient compliance. Methods: In situ gel formulations prepared by dispersion method using Carbopol ® 940/Carbopol ® 934 alone or in combination with hydroxypropyl methylcellulose (HPMC E4M). Formultaions were evaluated for appearance, pH, viscosity, gelling capacity, drug content and in vitro drug release. The optimized formulation was assessed for sterility and antimicrobial efficacy using disk diffusion technique in comparison to commercial eye drops (Albucid ® 10%). Results: The appearance of in situ gels were clear and free flowing in nature however, a viscous clear solution with no flow was produced for formulations consisting of 0.8% w/v Carbopol ® 940/Carbopol ® 934 and 2% w/v HPMC E4M. pH of all the formulations was within the range of 5.9 to 6.7. In situ gels with Carbopol ® 940 demonstrated higher viscosity compared to Carbopol ® 934 and drug release was sustained over a period of 8 hr. The selected formulation containing 0.8% w/v Carbopol ® 940 and 1.5% w/v HPMC E4M passed sterility test and demonstrated similar antimicrobial efficiency compared to commercial product. Conclusion: Carbopol ® /HPMC-based in situ gels have potential to improve patient's compliance by reducing the dosing frequency and could be a viable alternative to commercial product.

Experimental design, formulation and in vivo evaluation of a novel topical in situ gel system to treat ocular infections

“…The visual observation of time taken for gel formation, gel remains for the time period and gel dissolves was done for M1-M14 in situ gels [ 13 ]. Formulations (M5-M8, M10, M12 and M14) demonstrated immediate gelation and also was stable for an extended period ( Table 3 ).…”

“…The data in the Figs 1B and S2 demonstrate that the dilution with STF remarkably improved the viscosity of M1-M8 gels formulated with gellan gum as well as sodium alginate. This is due to the fact that these polymers (gellan gum, sodium alginate and HPMC) have the inherent capacity to produce gel in companion with mono or divalent cations, available in STF analogous to the lachrymal fluid [ 5 , 13 , 36 ]. This peculiar phenomenon endorses the in situ gelling characteristic of the M1-M8 gels.…”

“…Interpretations from the statistical model indicates that all the three polymers considerably influence the gel strength. In addition, the increase in the amount of gelling agents also improved the gel strength of the formulations, probably due to polymer’s potential to improve the gelling power in presence of electrolytes present in STF [ 5 , 13 , 36 ]. Concentration of HPMC also affects gel strength but at lesser extent as compared to gellan gum and sodium alginate.…”

“…Recently, low acyl gellan gum has received much attention as a gelling agent in various drug delivery systems because of its excellent mechanical properties and favorable rheological behavior [9][10][11]. The potential of gellan gum as an ophthalmic vehicle was also demonstrated in various studies [12,13].…”

Potential of Stimuli-Responsive In Situ Gel System for Sustained Ocular Drug Delivery: Recent Progress and Contemporary Research

“…Sheshala and colleagues developed a sulfacetamide sodium in the pH-responsive in situ gel by comparing two carbomer grades, namely Carbopol 934 and Carbopol 940 in combination with HPMC to minimize the acidity of carbomers as well as a viscosity enhancer [ 62 ]. The study found that Carbopol 940 had a higher viscosity compared to the Carbopol 934 with the feature of higher cross-linking intensity in Carbopol 940.…”