A Comparative Study of Modified Starches in Direct Compression Tabletting

ABSTRACT

S t a r c h e s have t r a d i t i o n a l l y been used i n t h e

pharmaceutical i n d u s t r y as f i l l e r , binder and d i s i n t e g r a n t .

Pharmaceutical grade s t a r c h e s a r e derived mainly f r o m maize

g r a i n s and potato tubers.

C u r r e n t advances i n t a b l e t t i n g technology, e s p e c i a l l y

the use of high-speed, mu1 ti-station r o t a r y t a b l e t presses,

and d i r e c t compression t a b l e t t i n g t e c h n i q u e s , have

n e c e s s i t a t e d t h e use of excipien ts with good flow and

compression c h a r a c t e r i s tics. Some pharmaceutical jrade

starches are t h e r e f o r e modified to meet t h e flow and

compression requirement f q r direct compression t a b l e t t i n g .

I n Nigeria, t n e r e are abundant sources of s t a r c h .

The p r o c e s s i n g technique for pharmaceutical grade s t a r c h

is . n o t far-fetched. Y e t Nigeria imports a l l its s t a r c h

requirement for drug production. T h i s work was designed

to e s t a b l i s h a simple and e f f e c t i v e technique for t h e

d e r i v a t i o n of pharmaceutical grade d i r e c t compression

s t a r c h . The technique i n view should be amenable to

i n d u s t r i a l application. It was a l s o d e s i r e d to e s t a b l i s h

any inherent differences between starches from t h e

d i f f e r e n t source studied. The sources were maize, Zea mays;

rice, Oryz a s a t i v a ,; c a s s a v a , Manihot -e cprlaln t -3 rnrn-8-m

Xan thosoma s a q i t t i f o l i u m .

E x t r a c t i o n of s t a r c h e s was essentially by t h e

wet-milling proce.ss. M o d i f i c a t i o n i n v o l v e d heat and a c i d

treatment. The flow and compression c h a r a c t e r i s t i c s of t h e

modified s t a r c h e s were e v a l u a t e d . Sta-Rx 1'500, a

commercial grade of d i r e c t compression s t a r c h was used as

b a s i s for comparison. The s t a r c h e s w e r e used i n the

f o r r r ~ u l a t i o n of d i r e c t l y compressed ascorbic a c i d ,

hydrochloro t h i a z i d e and c h l o r o q u i n e phosphate tablets,

These f o r m u l a t i o n s are examples of high dose, poorly

c o m p r e s s i b l e , l o w dose, poorly s o l u b l e and high dose

s o l u b l e t a b l e t f o r m u l a t i o n s r e s p e c t i v e l y . T a b l e t

proper ties e v a l u a t e d i n c l u d e d w e i g h t and drug c o n t e n t

uniformity, hardness, f r i a b i l i t y , d i s i n t e g r a t i o n time

and d i s s o l u t i o n rate.

The wet-milling p r o c e s s of starch e x t r a c t i o n

y i e l d e d white s t a r c h g r a n u l e s . The h e a t and acid

treatmcn t y i e l d e d p r o d u c t s w i t h e x c e l l e n t d i r e c t

compression c h a r a c t e r i s tics. The starch samples exhibited.

s p e c i e s s p e c i f i c i t y i n terms of i n d i v i d u a l powder

p r o p e r t i e s and t h e c h a r a c t e r i s tics of tablets compressed

from them.

. .

The modified s t a r c h e s may be ranked i n order of

i n c r e a s i n g f l o w a b i l i t y as modified rice ) cassava ) maize)

viii

cocoym stdrch. Thc r a n k i n g on the basis of h i g h

cornprcssibili t y is modified rice > cassava ) maize >

cocoyam s tdrch. The hydrochlorothiazide and ascerbic acid

t a b l ~ t sf o r r n u l a t t d w i t h t h e modified starches met

Pharmacopoeia1 r e q u i r e m e n t s for weight u n i f o r m i t y ,

d i s i n t e g r a t i o n time and dissolution of such tablets,

It w a s n o t p o s s i b l e to produce good chloroquine p h o s p h a t e

tablets by direction compression with the modified

s t a r c h e s . T h i s w a s attributed to t h e high dose n a t u r e

of t h i s drug.