title: Bilayer tablets of atorvastatin calcium and nicotinic acid: formulation and evaluation.
abstract: The objective of the study is to formulate bilayer tablets consisting of atorvastatin calcium (AT) as an immediate release layer and nicotinic acid (NA) as an extended release layer. The immediate release layer was prepared using super disintegrant croscarmellose sodium and extended release layer using hydroxypropylmethyl cellulose (HPMC K100M). Both the matrix and bilayer tablets were evaluated for hardness, friability, weight variation, thickness, and drug content uniformity and subjected to in vitro drug release studies. The amount of AT and NA released at different time intervals were estimated by HPLC method. The bilayer tablets showed no significant change either in physical appearance, drug content or in dissolution pattern after storing at 40 degrees C/75% relative humiding (RH) for 3 months. The release of the drug from the tablet was influenced by the polymer content and it was much evident from thermogravimetry/differential thermal analysis (TG/DTA) analysis. The results indicated that the bilayer tablets could be a potential dosage form for delivering AT and NA.
authors.affiliation: Department of Pharmaceutics, K.M. College of Pharmacy, Madurai, Tamil Nadu, India. nirmal21pharm@rediffmail.com
authors.forename: Jayabalan
authors.initials: J
authors.lastname: Nirmal
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Saisivam
authors.forename: Chintalapati
authors.initials: C
authors.lastname: Peddanna
authors.forename: Selvadurai
authors.initials: S
authors.lastname: Muralidharan
authors.forename: Sundaram
authors.initials: S
authors.lastname: Godwinkumar
authors.forename: Muthuraja
authors.initials: M
authors.lastname: Nagarajan
mesh_terms: D000069059:Atorvastatin; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004338:Drug Combinations; D004344:Drug Incompatibility; D004355:Drug Stability; D004356:Drug Storage; D005079:Excipients; D006244:Hardness; D006538:Heptanoic Acids / Q000008:administration & dosage* / Q000737:chemistry*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000008:administration & dosage* / Q000737:chemistry*; D065347:Hypromellose Derivatives; D008747:Methylcellulose / Q000031:analogs & derivatives; D009525:Niacin / Q000008:administration & dosage* / Q000737:chemistry*; D011758:Pyrroles / Q000008:administration & dosage* / Q000737:chemistry*; D012995:Solubility; D013607:Tablets
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004338:Drug Combinations; D005079:Excipients; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D011758:Pyrroles; D013607:Tablets; D009525:Niacin; D065347:Hypromellose Derivatives; D008747:Methylcellulose; D000069059:Atorvastatin; D002266:Carboxymethylcellulose Sodium