DEVELOPMENT AND EVALUATION OF A CO-PROCESSED EXCIPIENT FROM ACID HYDROLYZED CASSAVA STARCH, GELATIN AND LACTOSE (STARGELAC) IN TABLET FORMULATIONS, A RESEARCH PROJECT TOPIC ON MICROBIOLOGY
ABSTRACT
Co-processed excipients are a mixture of two or more existing excipients at subparticle level. These multipurpose excipients have significantly reduced the number of incorporating excipients in the tablet. The aim of this work is to design and prepare a co-processed excipient from acid hydrolyzed cassava starch, gelatin and lactose and evaluate its functionality in tablet formulations.Native cassava starch (NCS) extracted from cassava tubers (Â Mannihot esculentacrantz ) was modified chemically by acid hydrolysis using the
process  described   by  the  World    Intellectual   Property  Organization,    to obtain       acid hydrolyzed cassava starch. The flow, compression and tableting properties of acid hydrolyzed cassava starch were evaluated using flow rate, angle of repose, bulk and tapped densities, Hausner‟s ratio, Carr‟s (compressibility) index, friability, crushing strength and disintegration time. Acid hydrolyzed starch (AHS-24) was co-processed with gelatin and lactose in ratios of 52.5:5:42.5; 42.5:5:52.5; 32.5:5:62.5; 22.5:5:72.5 and 12.5:5:82.5 using the co-drying method. These initial batches of co-excipients that were developed were evaluated for their physicochemical and tableting properties. Further characterization utilized: hydration capacity, Fourier Transfor Infrared Spectroscopy (FTIR) study, Differential Scanning calorimetry (DSC), compaction indices from Heckel and Kawakita analyses, dilution potential and mechanical strength properties such as tensile strength and brittle fracture indices as indicators. Paracetamol and ascorbic acid tablets were prepared by direct compression using StarGeLac as filler-binder-disintegrant and the tablet properties were evaluated and compared with those prepared with Starlac® and Ludipress® as reference materials. The evaluation showed that the average flow rate, angle of repose and Carr‟s index of native cassava starch were 0.9 g/sec, 38.7o and 36.84 %, respectively. The corresponding values for acid hydrolyzed cassava starch (after 24 h exposure time) were 4.6 g/sec, 16.2 o and 14.9 % , showing improved functionality. Also the average flow rate, angle of repose and Carr‟s index of StarGeLac (batch IV, component ratio of acid hydrolyzed cassava starch, gelatin, lactose 22.5:5:72.5) were 50.8 g/sec, 28.9o and 16.6 %, respectively. Tablets prepared, without model drugs, using StarGeLac IV had crushing strength of 7.9 Kgf, friability of 0.8 % and disintegrated witin 6.53 minutes. The results also show that StarGeLac IV exhibited satisfactory hydration capacity, showed no evidence of chemical changes through FTIR and DSC studies and satisfactorily compressed 40 % and 33.3% of paracetamol and ascorbic acid respectively. Heckel and Kawakita plots also showed that StarGeLac consolidates by plastic deformation but that the onset was slow (higher Py value).The study also revealed that tablets of paracetamol and ascorbic acid, used as model drugs, that were prepared using StarGeLac were comparable to those prepared with Starlac ® and Ludipress®. Paracetamol tablets prepared with StarGeLac exhibited higher mean crushing strength and mean disintegration time than the ascorbic acid counterpart but both paracetamol and ascorbic acid tablets prepared with the commercial co-processed excipients had faster disintegration times
CHAPTER ONE
INTRODUCTION
1.1Â Â Â Â Â PHARMACEUTICAL TABLETS
The oral route is the most common way of administering drugs and among the oral dosage forms, tablets of various kinds are the most common type of solid dosage form in contemporary use (Kaur et al., 2011).
Modern tablet compression was instituted in England in 1844 by William Brockedon (1787-1854) who established early procedures for making compressed pills.
