EVALUATION OF THE BINDING AND SUSPENDING PROPERTIES OF BAGGASE-DERIVED METHYLCELLULOSE

ABSTRACT

Sourcing of raw materials for use in pharmaceutical industries is a continuing challenge. Excipients, which form the bulk of a dosage form, are derived either from natural sources or synthesized wholly or semi-synthesized. The absence of an ideal excipient material continues to spur research towards identifying and developing excipients from various sources. One of such potential sources is sugar cane bagasse which is an abundant agricultural waste. This work, investigated the properties of derived methylcellulose from sugarcane and evaluated its suitability as a pharmaceutical grade excipient.

Methylcellulose was derived from locally sourced bagasse in Zaria, Nigeria by standard extraction procedures. The bagasse-derived methylcellulose (BDMC) was characterised by studying its physicochemical properties, namely moisture content, particle size distribution, shape and viscosity. The stability and flow properties of the powder were also investigated. To confirm the quality of the BDMC, the measured properties were compared with those of a high- grade standard methylcellulose (Methocel®). To ascertain its suitability as an excipient, its effectiveness as a binder in a large dose formulation was studied using 500 mg paracetamol tablets. Its use as a suspending agent was investigated in co-trimoxazole and metronidazole suspensions.

The physical properties such as mean particle size, size distribution, shape, and viscosity of BDMC compared favourably with those of Methocel®. The disintegration time, crushing strength, friability and dissolution profiles of tablets formulated with BDMC as binder were very similar to those prepared with Methocel®. BDMC and Methocel® containing suspensions exhibited pseudoplastic flow behaviour as indicated by their reduced viscosity values. The redispersibility study revealed that, both BDMC and Methocel® influenced the intrinsic

properties of the active constituents in the suspension formulations. Suspensions made with Methocel® were more flocculated than those formulated with BDMC.

Results of the various parameters studied indicated that concentration of 2 per cent of the BDMC can be used as a binder to produce pharmaceutical grade tablets. It is also a suitable suspending agent for producing flocculated, easily dispersible suspensions of indiffusible pharmaceutical active ingredients such as co-trimoxazole and metronidazole.