The field of ocular drug delivery is one of the interesting and challenging endeavors facing the pharmaceutical scientist. Novel approaches for ophthalmic drug delivery need to be established to increase the ocular bioavailability by overcoming the inherent drawbacks of conventional dosage forms. In situ hydrogels are instilled as drops into the eye and undergoes a sol-to-gel transition in the cul-de-sac, improved ocular bioavailability by increasing the duration of contact with corneal tissue, thereby reducing the frequency of administration. The purpose of the present work was to develop an ophthalmic drug delivery system using three different gelling agents with different mechanisms for in situ gelation of Moxifloxacin hydrochloride, a fluoroquinolone antibiotic. polyox (a pH-sensitive gelling agent), sodium alginate (an ion-sensitive gelling agent), and poloxamer (a temperature-sensitive gelling agent) were employed for the formation of in situ hydrogel along with HPMC K4M as viscofying agent, which increases the residence time of the drug in the ocular cavity. The promising formulations MF(4), MF(5), and MF(9) were evaluated for pH, drug content, in vitro gelation, in vitro drug release, in vivo drug release, ocular irritation, and stability. Percent drug content of 98.2, 98.76, and 99.43%; viscosity of 15.724 × 100, 16.108 × 100, and 15.213 × 100 cP at 20 rpm, cumulative percent release of 75.364, 74.081, and 71.752%, and C (max) of 1,164.16, 1,187.09, and 1,220.58 ng/ml was observed for formulation MF(4), MF(5), and MF(9), respectively. The developed formulations were therapeutically efficacious, stable, and non-irritant and provided sustained release of the drug over 8 h.

Novelty of the WorkNeostigmine Bromide is very known drug for the treatment of myasthenia gravis. However, its conventional oral route has disadvantage of poor bioavailability. Literature reports the evidence of good intranasal absorption of Neostigmine Bromide. Hence, an attempt has been made to develop intranasal mucoadhesive microspheres to increase the bioavailability and reduce the dosing frequency of the drug. IntroductionThe most desirable and convenient method of drug administration is the oral route because of their ease of administration. But lack of systemic absorption through the gastrointestinal tract led to research on alternate routes of drug delivery such as parenteral, intramuscular, subcutaneous, transdermal, etc [1]. Intranasal (IN) administration is a needle free and hence an ideal alternative to the parenteral route for systemic drug delivery. Nasal mucosa consists of a rich vasculature and a highly permeable structure for systemic absorption. Drug administration through the nasal cavity is easy and convenient. Avoidance of first pass metabolism is the main advantage of nasal route of drug delivery [2,3]. IN delivery is non-invasive, essentially painless, does not require sterile preparation, and is easily and readily administered by the patient or a physician, e.g., in an emergency setting. Given these positive attributes, it is logical to consider IN administration when developing new therapeutics, or when extending the life or improving the profile of an existing drug [4,5]. Subsequent to a drug's passage through the mucus, there are several mechanisms for absorption through the mucosa. These include transcellular or simple diffusion across the membrane (for lipophilic drugs), paracellular transport via movement between cell (for water soluble drugs) and transcytosis by vesicle carriers [6,7].Microsphere carrier systems made from the biodegradable polymers have attracted considerable attention for several years in sustained drug delivery. However, the short residence time at the site of absorption could be overcome by coupling bioadhesion characteristics to microspheres and developing bioadhesive microspheres with the help of bioadhesive polymers [8,9]. Neostigmine Bromide -a cholinesterase inhibitor is widely used for the treatment of Myasthenia Gravis. It is presently marketed in conventional dosage form as a tablet in usual strength of 15-30 mg for peroral route [10]. Extent of absorption of drug through oral route is only 1-2% of 30 mg of administered dose [11]. Hence there is need of novel nasal drug delivery system for the treatment of Myasthenia Gravis. To overcome inherent drawbacks associated with conventional dosage forms of Neostigmine Bromide, an attempt is being made in the present research work to develop an alternative drug delivery system in the form of Nasal mucoadhesive microspheres to increase the rate and extent of absorption and to reduce the dosing frequency of the formulation. AbstractPurpose: Neostigmine bromide, a cholinesterase inhibitor is conventionally given ...