Original Article FORMULATION, OPTIMIZATION, AND EVALUATION OF IN-SITU GEL OF MOXIFLOXACIN HYDROCHLORIDE FOR OPHTHALMIC DRUG DELIVERY CHITRA GUPTA 1 , VIJAY JUYAL 2 , UPENDRA NAGAICH 3* 1 Lloyd Institute Of Management & Technology,11,Knowledge Park 2,Greater Noida, UP, India, 2 Department of Pharmaceutical Sciences, Bhimtal Campus, Kumaun University, Nainital, Uttarakhand, India, 1,3 Amity Institute of Pharmacy, Amity University Noida, UP, India Email: upendra_nagaich@hotmail.com Received: 20 Oct 2018, Revised and Accepted: 05 Mar 2019 ABSTRACT Objective: The present study emphasizes the synthesis, optimization, and evaluation of ocular in-situ gel for ophthalmic drug delivery against conjunctivitis. Methods: Pre-formulation studies on the drug and polymers were carried out, which included the study of various physicochemical properties of the drug and drug-polymer compatibility studies. The 12 different formulations were further pre-optimised by Taguchi method for determining the number of influential factors. Furthermore, the formulation optimization was done by using ‘Box–Behnken’ design (BBD) (Design expert 10 software) for assessing the effect of formulation variables on product characteristics viz. viscosity, gelation temperature (GT), and mean release time (MRT). About 13 suggested runs of the experiment were carried out and formulations were optimised. Finally, three batches of the optimised formulation were prepared and evaluated for in vitro drug release, isotonicity of formulation, anti-microbial potential, ocular irritancy, and accelerated stability testing. Results: Pre-formulation study confirmed the purity, solubility, and compatibility of drug measured by λmax, partition coefficient, stability study, and Fourier-transform infrared spectroscopy (FTIR) analysis. Taguchi screening method suggested about 12 different formulations and 3 most prominent influential factors including viscosity, GT, and drug release. 13 different formulations designed based on ‘BBD’ method were further optimised by considering the most influential factors suggested by Taguchi screening. The in vitro evaluation of the optimised formulation gave satisfactory results in terms of drug release, and anti-microbial activity. It was found to be isotonic with no ocular irritancy. Further, the preparation immediately transformed from sol to gel upon administration into cul-de-sac region of the eye due to multi-dimensional approaches utilised for in- situ gel formation namely temperature change Pluronic, ion sensitivity due to Gellan-gum, pH sensitivity because of Carbopol. Conclusion: The optimised in-situ gelling ocular drug formulation showed promising potency for ophthalmic drug delivery with no irritancy due to the multifactorial mechanism. Keywords: Ocular in-situ gel, Pluronic F-127, Gellan-gum, Carbopol, Taguchi screening, Box–Behnken design © 2019 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/) DOI: http://dx.doi.org/10.22159/ijap.2019v11i4.30388 INTRODUCTION In-situ forming formulation is an advanced system of drug delivery in which in-situ phase transition occurs on the surface at the site of application. The preparations are convenient to administer and use over other drug delivery systems [1]. The phase transformation of dosage form from liquid to gel, in in-situ gelling formulations, takes place due to changes in physical or chemical factors, which include, changes in temperature, pH, solvent, ionic concentration and trigger one or more mechanism for transforming the liquid into gels. Since, the mechanisms are not dependent on any external factors which enhances the simplicity and reliability of formulation, encouraging self-administration and improved patient compliance [1]. Previously researchers have attempted to develop formulations to enhance the precorneal residence time by injecting the drug in cul-de-sac region of eye,. Using the polymer dependent singular approach such as pH dependence (cellulose acetophthalate), temperature dependent (polyoxyethylene polymer), in a single polymer containing formulation; the concentration of Pluronic required to achieve enough gelling property to avoid being oozed out by tears was 30% [2]. Carbopol possess self-acidic nature and may irritate the individual’s eye which leads to excessive tearing and wash out of the formulation [3]. The time required to form gel is significantly large in case of Gellan-gum, which sometimes leads to oozing out of the instilled formulation due to reflex tearing before it can gel. Thus, these formulations dependent on the singular mechanism are more susceptible to failure. Also, the concentration of polymer required to achieve desirable properties is often too high, which ultimately increases the total volume and cost of manufacturing of formulation and more importantly overexposure of delicate tissues of eyes to the high concentration of polymers. Thereby, limiting the scope of the formulation [4]. Whereas, the combined use of polymers can help to develop a robust formulation that may reduce the probability of formulation failure and reduces the quantity of polymers required to develop formulation [5]. Thus, to target the limitations of the traditional formulation including rapid exclusion, insignificant ocular bioavailability and eye irritation we have proposed an innovative formulation of Moxifloxacin hydrochloride based on multifactorial approaches. We have pursued the combination of numerous mechanisms to develop a new in- situ gelling formulation having a relatively small concentration of each polymer. The present investigation includes the development of an optimised formulation based on pre-formulation studies and its evaluation. For this, the different sets of combined polymers in miscellaneous concentration was used to the developed formulation and optimised by design expert software (Design-Expert® 10 software) for utmost release of the drug, apposite viscosity at ocular site and optimised gelation temperature (GT). Furthermore, the ocular irritancy was observed in the rabbit’s eye for 14 d. MATERIALS AND METHODS Materials Moxifloxacin hydrochloride was obtained as a gift sample from INTAS pharmaceuticals, Ahmedabad, India. Pluronic F-127, Carbopol, Gellan-gum were obtained as a gift sample from Jubilant life sciences India. All other chemicals were of analytical grade. Microbial culture Pseudomonas aueroginosa and Staphylococcus aureus were obtained from microbial type culture collection (MTCC); MTCC catalog no. of both are 424 and 96 respectively, and Gene Bank, CSIR-Institute of microbial technology, India. Pre-formulation studies Melting point The melting point of active pharmaceutical ingredient (API) was determined using digital melting point apparatus. A capillary tube having the diameter of 1.9 mm was broken in the length of 6 cm and one end of the tube was sealed off. Capillary tubes were filled with the sample up to I In nt te e r rn na a t ti io o n na al l J Jo ou u r rn na a l l o of f A Ap pp p l li ie e d d P Ph h a ar rm m a ac ce e u u t ti ic cs s ISSN- 0975-7058 Vol 11, Issue 4, 2019