Development and optimization of ganciclovir-loaded carbopol topical gel by response surface methodology for enhanced skin permeation

Low permeability is one of the barriers to the bioavailability of drugs through the oral route. The purpose of the present study was to design and optimize a sustained release and highly permeable hydrogel formulation of ganciclovir (GCV) by using response surface methodology (RSM). Carbopol 934P was used as a gelling agent, with two permeation enhancers, i.e., propylene glycol (PG) and oleic acid (OA), which were selected as variables X 1 and X 2 , respectively. A total number of 13 runs prepared by using a central composite rotatable design (CCRD), followed by the preparation and evaluation of various parameters, including flux, lag time, K p , and the rheological studies were evaluated. FTIR analysis showed that there was no interaction between the drug, polymer, and other excipients. The outcomes of ex vivo permeation studies have reviled that the values of flux, lag time, and k p were found to be 2.08800 ± 0.008, −6.982638 ± 0.01, −2.6917 ± 1.21, −29.7116 ± 0.68, and 0.00020, −0.00069, respectively. The spreadability index and the viscosity of the gel formulations were between the range of 2.63 ± 0.12–3.50 ± 0.08 and 5013.66 ± 1.69–5077.66 ± 2.05, respectively. On the other hand, the pH of all preparations was maintained at 7.02–7.13 pH to avoid skin irritation. After evaluating the said parameters, the composition for the optimized formulation is PG 5gm, OA 0.4gm, and carbopol 0.5gm. Furthermore, the findings have advocated that the hydrogels could be used, not only to deliver the drug in a sustained manner but also to improve the permeation of the drug and hence its bioavailability.