This study was conducted to develop floating osmotic tablets of Nizatidine, a H2 receptor antagonist, to release the drug as two distinct pulses separated by a lag time that achieve plasma concentration profiles varying in a circadian rhythm fashion, for the chronotherapy of ulcer. Floating osmotic tablets were developed using effervescence method consisted of three different steps viz, preparation of floating sustained release drug containing tablets followed by time-lagged (4 hrs) coating with hydrophobic rupturable polymer, ethyl cellulose (EC), and finally compression coating with immediate release dose of nizatidine and supporting buoyant layer. Three ratios of Ethyl cellulose to HPMC E15 (32.5:67.5, 50:50, and 67.5:32.5) at three coating levels (5%, 10%, 15%) were used to optimize the lag time (4 hrs). Carbopol 934P, cross povidone and sodium bicarbonate were used in buoyant layer. The developed floating osmotic tablets by effervescence method were evaluated for preformulation parameters, weight variation, thickness, hardness, friability, drug content, content uniformity, In-vitro floating properties, and In-vitro drug release. The optimized formulation provided expected two-phase release pattern of Nizatidine with initial immediate dose release in 30 min and then lag time 4 hrs of no drug release followed by sustained release for 8hrs in stomach during floating.

Availability of modern medicine increased all over the world due to huge expansion of the global Pharma market. At the same time misuse as well as accessibility of the most of essential drugs to majority of the population was denied due to cost-effectiveness of healthcare delivery combined with poor procurement policies and poor prescribing practices. During the recent years, the national list of India has assumed immense importance to improve access to medicines in India. It is therefore necessary to understand policies and guidelines followed in developing WHO essential drug list and national list of essential medicines. In this review article history of essential drug list and important inclusions in NLEM 2015 and WHO EML 2015 were highlighted.

Recent advances in chronotherapeutics led to the development of pulsatile drug delivery systems which effectively delivered the drug at specified time. Diseases like asthma, arthritis, cancer, diabetes, hypertension, ulcer, hypercholesterolemia, congestive heart failure, stroke etc. show different day night pattern in onset and symptoms exacerbation. Pulsatile drug delivery systems deliver the drug at right time in desired levels providing the multiple benefits over the conventional dosage forms. According to the circadian rhythms of the body drug is facilitated to completely release after a lag time especially for drugs eliciting higher first pass effect and where nocturnal dosing is required these systems are highly beneficial. This review epitomizes the special focus on chronotherapeutics, various approaches in chronotherapeutic drug delivery and applications.

ABSTRACT:The aim of the present study was to develop sustained release formulation of Isoniazide to maintain constant therapeutic levels of the drug for over 12 hrs. Various polymers such as Guar gum, HPMCK100 M, PEG 6000 and Carbopol 934 p were employed as polymers. Isoniazide dose was fixed as 100 mg. Total weight of the tablet was considered as 400 mg. Polymers were used in the concentration of 100, 150 and 200 mg. All the formulations passed various physicochemical evaluation parameters and they were found to be within limits. Whereas from the dissolution studies it was evident that the formulation (F6) showed better and desired drug release pattern i.e.,96.10 % in 12 hours. It followed zero order release kinetics.

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