Controlled release (CR) dosage forms have been extensively used to improve therapy with several important drugs. However, the development processes are faced with several physiological difficulties such as the inability to restrain and localize the system within the desired region of the gastrointestinal tract and the highly variable nature of the gastric emptying process. This variability may lead to unpredictable bioavailability and times to achieve peak plasma levels. On the other hand, incorporation of the drug in a controlled release gastroretentive dosage forms (CR-GRDF) which can remain in the gastric region for several hours would significantly prolong the gastric residence time of drugs and improve bioavailability, reduce drug waste, and enhance the solubility of drugs that are less soluble in high pH environment. Gastroretention would also facilitate local drug delivery to the stomach and proximal small intestine. Thus, gastroretention could help to provide greater availability of new products and consequently improved therapeutic activity and substantial benefits to patients. Controlled gastric retention of solid dosage form may be achieved by the mechanisms of floatation, mucoadhesion, sedimentation, expansion or by a modified shaped system. The purpose of this paper is to review the recent literature and current technology used in the development of gastroretentive dosage forms.

Magnesium supplementation can produce a favourable effect on FPG, HDL, LDL, TG and SBP. Therefore, magnesium supplementation may decrease the risk T2D associated cardiovascular diseases, although future large RCTs are needed for making robust guidelines for clinical practice.

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The present study performed by preparation and evaluation of floating tablets of Silymarin as model drug for prolongation of gastric residence time. Floating effervescent tablets were formulated by various materials like hydroxypropyl methylcellulose (HPMC) K 4M, K 15M, psyllium husk, swelling agent as crospovidone and microcrystalline cellulose and gas generating agent like sodium bicarbonate and citric acid and evaluated for floating properties, swelling characteristics and in vitro drug release studies. Floating noneffervescent tablets were prepared by polypropylene foam powder and different matrix forming polymers like HPMC K 4M, Carbopol 934P, xanthan gum and sodium alginate. In vitro drug release studies were performed and drug release kinetics evaluated using the linear regression method was found to follow both the Higuchi and the Korsemeyer and Peppas equation. The drug release mechanism was found fickian type in most of the formulations. The developed floating tablets of Silymarin may be used in clinic for prolonged drug release for at least 24 h, thereby improving the bioavailability and patient compliance.

Background: Quetiapine fumarate, a 2nd generation anti-psychotic drug has oral bioavailability of 9% because of hepatic first pass metabolism. Reports suggest that co-administration of drugs with lipids affects their absorption pathways, enhances lymphatic transport thus bypassing hepatic first-pass metabolism resulting in enhanced bioavailability. Objective: The present work aimed at developing, and characterising potentially lymphatic absorbable Solid Lipid Nanoparticles (SLN) of quetiapine fumarate by Quality by Design approach. Method: Hot emulsification followed by ultrasonication was used as a method of preparation. Precirol ATO5, Phospholipon 90G and Poloxamer 188 were used as a lipid, stabilizer and surfactant respectively. A32 Central Composite design optimised the 2 independent variables, lipid concentration and stabilizer concentration and assessed their effect on percent Entrapment Efficiency (%EE: Y1). The lyophilized SLNs were studied for stability at 5 ±3οC and 25 ± 2οC/60 ± 5% RH for 3 months. Results: The optimised formula derived for SLN had 270mg Precirol ATO5 and 107mg of Phospholipon 90G giving %EE of 76.53%. Mean particle size was 159.8nm with polydispersity index 0.273 and zeta potential -6.6mV. In-vitro drug release followed Korsmeyer-Peppas kinetics (R2=0.917) with release exponent n=0.722 indicating non-Fickian diffusion. Transmission electron microscopy images exhibited particles to be spherical and smooth. Fourier-transform infrared spectroscopy, differential scanning calorimetry and X-ray diffraction studies ascertained drug-excipient compatibility. Stability studies suggested 5οC as appropriate temperature for storage and preserving important characteristics within acceptable limits. Conclusion: Development and optimisation by Quality by Design were justified as it yielded SLN having acceptable characteristics and potential application for intestinal lymphatic transport.