An evaluation of starch obtained from pearl millet - Pennisetum typhoides. As a binder and disintegrant for compressed tablets

The binding and disintegrant properties of millet starch obtained from Pearl Millet - Pennisteum typhoides (Staph. Burn, and Hubb.) Fam. Gramineae have been evaluated using tablet formulations of four drugs.

The results showed that Millet starch compared favourably with Maize starch with regards to most of the parameters used to evaluate the tablets. It can be safely concluded that millet starch is suitable for use as a binder and disintegrant in tablet formulations.     

Evaluation of sorghum starch as a tablet excipient

The suitability of sorghum starch as a binder and disintegrant at various concentrations in diverse tablet formulations have been investigated. Sodium bicarbonate and calcium carbonate were used as soluble and insoluble inorganic medicinal substances in various tablet formulations.

The effect of sorghum starch on the physical properties of the tablets were compared with those formulated with maize starch using the same concentrations of binder and disintegrant under the same experimental conditions.

The observations show that sorghum starch can be used as binder and disintegrant in tablet formulations. The indication is that the starch exhibit about twice the disintegrant power and about the same binding efficacy compared to maize starch.     

On the Similarity of Sodium Starch Glycolate from Different Sources

Abstract

The physico-pharmaceutical properties of different batches of two brands of sodium starch glycolate have been investigated as disintegrant in direct compression. Differences in disintegration efficiency were found to be related to the purity of the products. The differences, however, were too small to have practical significance. The currently available low-sodium chloride content sodium starch glycolates may consequently be considered as being pharmaceutically equivalent, when used as disintegrant in tablet formulations.     

The Binding and Disintegrant Properties of the Corn Starch Fractions: Amylose and Amylopectin

Abstract

Corn Starch USP consists of the two glucose polymers, amylose and amylopectin, whose normal ratio is 27%:73%. This study was initiated to determine whether a variation in this ratio would have any benefit in pharmaceutical granulations. Starch pastes prepared by varying the amylose/amylopectin ratio were used to granulate a dicalcium phosphate system and the resulting tablet properties were evaluated.

Physical mixtures of the polymers and also special hybrid polymer mixtures were studied. Binding and disintegrant properties of the starch fractions do vary with the amylose/ amyloptectin ratio and with the degree of starch hydrolysis during the heating (cooking) phase of starch paste preparation. The results of this study give some indication as to the binding and disintegrant activity of starch and its fractions.     

The Influence of the Swelling Characteristics of Starch and Starch Derivates on the Disintegration of Powders,Packed in Hard Gelatin Capsules

Abstract

Starch and starch derivates are frequently used in tablets to improve the disintegration. Their disintegrating action has mainly been attributed to the swelling of the particles when they are immersed in an aqueous solution. It has been assumed that tablet disintegration would be related to the ratio between the pore diameter and the linear growth of the disintegrant particles. The present work investigates the relationship between disintegrant swelling, pore diameter and drug release rate for loosely packed powderbeds in hard gelatin capsules.     

Evaluation of Fast Disintegrants in Terfenadine Tablets Containing a Gas-Evolving Disintegrant

Abstract

Effects of four fast disintegrants on the dissolution of terfenadine tablets containing the gas-evolving disintegrant, CaC0₃, were evaluated. In addition, effects of presence of starch along with the fast disintegrants on the dissolution of the tablets were examined. Dissolution data were treated to give dissolution parameters which reflected efficiency of the disintegrant combinations. The four fast disintegrants improved disintegration/dissolution of the original formulation. The relative efficiency of improvement was in the order crospovidone < Ac-Di-Sol < Primojel < low substituted hydroxypropylcellulose. The presence of starch advertently affected the role of the fast disintegrants. Scanning electron microscope studies revealed that starch covered the drug-containing granules and other particles of the tablet. pH changes during dissolution of representative tablets in 0.1 N HCl solutions were determined at specific time intervals. The progressive decrease in rates of acid consumption as a function of the amount of starch, along with the SEM studies, suggested that a barrier existed around the tablet particles. The barrier was generated by the swelled starch grains and was responsible for the loss of the dissolution-improving capacity of the fast disintegrants. Furthermore, the barrier interfered with the diffusion of the hydronium ions and therefore, impaired the function of the disintegrant combination.     

An Evaluation of Hydroxypropyl Starch as Disintegrant and Binder in Tablet Formulation

Hydroxypropyl and pregelatinized hydroxypropyl starch were evaluated as disintegrant and binder in tablet formulations. The study showed that the use of pure hydroxypropyl starch showed no advantage as a disintegrant or binder over the actually available tablet ingredients. Pregelatinized hydroxypropyl starch showed some good disintegrating properties and could be used as a binder in wet granulation.     

The Effect of Recompression on Disintegrant Efficiency in Tablets Prepared by wet Granulation

Abstract

The efficiency of three modern disintegrants, Explotab, Ac-Di-Sol and Polyplasdone XL, has been investigated following rework of a wet massed, slowly eroding, tablet formulation. When the disintegrants were placed extra-granularly it was found that only Explotab retained good efficiency following rework. All disintegrants placed intra-granularly had rework efficiencies that were essentially the same as the control (no disintegrant). However, the addition of 2% extra-granular disintegrant prior to the second compression restored tablet disintegration behaviour for Polyplasdone XL and partially for Ac-Di-Sol.

Two of the factors potentially affecting the reworkability of disintegrants (comminution and regranulation) were also investigated. Regranulation caused Ac-Di-Sol and Explotab to significantly lose disintegrant efficiency. However milling alone caused no reduction in efficiency of any disintegrant.     

An Evaluation of Croscarmellose as a Tablet Disintegrant in Direct Compression Systems

Abstract

The disintegrant actions of croscarmellose type A (Ac-Di-Sol, FMC Corp.) and croscarmellose type B (CLD-2, Buckeye Cellulose Corp.) have been compared to that of corn starch in direct compression tablets in which microcrystalline cellulose (Avicel PH101, FMC Corp.) was the matrix. Two types of formulations were examined using either pyridoxine or hydrochlorothiazide as drug. The data clearly shows that both forns of croscarmellose are markedly superior to corn starch and are active at quite low concentrations. The CLD-2 may promote more rapid dissolution in some systems than Ac-Di-Sol.     

Comparison of Disintegrant and Binder Activity of Three Corn Starch Products

Abstract

This study demonstrates the differences obtained when using different corn starch products as both binder and disintegrant in pharmaceutical tablets. Formulations made with Fluftex W, Tablet White and Purity 21 starches were compared. In addition, Avicel PH101 was used in this study as a benchmark component whose properties are well understood.

Four test formulations containing hydrochlorothiazide were prepared by wet granulation. Starch was incorporated in both powder and paste form. All granulations were found to possess similar traits when evaluated based upon geometric mean diameter, particle size distribution, bulk/tap densities, powder flow rate and surface characteristics.

Tablets prepared from these granulations were shown to be similar when evaluated for degree of friability, weight and content uniformity. All starch formulations disintegrated within 30 seconds and produced similar dissolution profiles. Tablets produced with Avicel, however, were found to exhibit significantly longer disintegration times than the starch formulations. In addition, these tablets displayed a dissolution profile that was significantly different than the starch formulations, particularly during the earlier stages of the dissolution process.

When monitoring compression and ejection forces required to produce tablets of the same degree of hardness (≈6kg), Fluftex W and Tablet White granulations were found to use significantly lower forces than the Purity 21 granulation. This may be indicative of Fluftex W and Tablet White's superiority over Purity 21 in terms of binder capacity.     

Carboxymethylstarches in Wet Granulation

Abstract

Commercialized carboxymethystarches (CMS) are both carboxyme-thylated and cross linked potato starch.

The influence of carboxymethylation and cross linkage on the disintegrating properties of starch are studied.

Tablets are made with acetaminophen as drug, Emcompress as diluant, Magnesium stearat as lubricant, and potato starch or its derivatives as disintegrants.

Tablets are prepared by direct compression or by wet granulation with the disintegrant intervening only in internal phasis.

Five disintegrants were studied, with two different concentrations:

native potato starch

potato starch simply cross linked

potato starch simply carboxymethylated

two potato starches both cross linked and carboxymethylated at two different degrees

Compressibility of powders blending and grain for compression are discussed.

The hardness, the tablet disintegration and the rate of drug dissolution are studied.

The results showed that the simply carboxymethylated starch has a totally different behaviour after direct compression or wet granulation. The poor results after wet granulation could be imputed to the bursting of starch granules during grain drying. Since it has lost its granular structure, the carboxymethylated starch will only allow a poor disintegration and a slow dissolution of the drug.

A very similar behaviour of native and simply cross linked starch: the results of which are bad for tablets either prepared by wet granulation or direct compression.

A very similar behaviour of the starches both carboxymethylated and cross linked, allowing a very good disponibility, either with tablets prepared by direct compression or wet granulation. These experiments prove :

the need for an sufficient cross linkage for CMS in a wet granulation process     

Comparison of Disintegrant and Binder Activity of Three Corn Starch Products

Abstract

This study demonstrates the differences obtained when using different corn starch products as both binder and disintegrant in pharmaceutical tablets. Formulations made with Fluftex W, Tablet White and Purity 21 starches were compared. In addition, Avicel PH101 was used in this study as a benchmark component whose properties are well understood.

Four test formulations containing hydrochlorothiazide were prepared by wet granulation. Starch was incorporated in both powder and paste form. All granulations were found to possess similar traits when evaluated based upon geometric mean diameter, particle size distribution, bulk/tap densities, powder flow rate and surface characteristics.

Tablets prepared from these granulations were shown to be similar when evaluated for degree of friability, weight and content uniformity. All starch formulations disintegrated within 30 seconds and produced similar dissolution profiles. Tablets produced with Avicel, however, were found to exhibit significantly longer disintegration times than the starch formulations. In addition, these tablets displayed a dissolution profile than was significantly different than the starch formulations, particularly during the earlier stages of the dissolution process.

When monitoring compression and ejection forces required to produce tablets of the same degree of hardness (≈6kg), Fluftex W and Tablet White granulations were found to use significantly lower forces than the Purity 21 granulation. This may be indicative of Fluftex W and Tablet White's superiority over Purity 21 in terms of binder capacity.     

An Attempt at Bringing to Light a “Phase Inversion” in a Binary Mixture of Two Dimensional Rounded Particles

Abstract

It has been demonstrated previously in our Laboratory that the disintegrant concentration corresponding to an interparticular network between drug or diluent particles in tablets may be calculated.

When the disintegrant concentration increases little by little, for a critical concentration, a sudden modification of the physical properties of the powder mixture and of the resulting tablets can be observed.

A new structure is set up in the tablet: in a way, a “phase inversion” is produced.

This experimental critical concentration is the same as the calculated critical concentration for more or less rounded particles.

An investigation into the physical properties of binary powder mixtures and of resulting tablets is carried out when increasing, little by little, the quantity of disintegrant particles: Starches and their derivatives, cross linked PVP, are more particularly studied.

The authors study:

• – The flowing properties of powder mixtures

• – The compressibility (Hardness/Compression forces, transmission forces through the powder mixture during compression, compression cycles…)

• – The physical properties of tablets (hardness, structure hydrophilicity, disintegration time and drug dissolution).

Several formulations were studied. The results point out the setting up of the continuous network of the small particles between the larger particles for the calculated critical concentration. The same theory may be applied to the hydrophilization of powders in hard gelatin capsules and to all the more o r less rounded two dimensional particles in a mixture.     

Disintegrating Agents in Hard Gelatin Capsules. Part II: Swelling Efficiency

Abstract

The wicking and swelling properties of pure disintegrants were investigated from plugs prepared under conditions similar to those used in encapsulation of powder mixtures into hard gelatin capsules. Pure AcDiSol exhibited the greatest wicking and swelling action followed by Primojel, Polyplasdone-XL 10 and corn starch. The swelling properties of pure disintegrants correlated best with the swelling of formulation mixtures and the efficiency of these materials in enhancing the dissolution of hydrochlorothiazide. A change in the penetrating liquid from dilute acid to water altered the liquid uptake and swelling of AcDiSol and Primojel but not those of Polyplasdone-XL 10 and corn starch. The extent of swelling per unit volume of liquid absorbed, defined as the swelling efficiency, varied with time and type of disintegrant. The swelling efficiencies of pure AcDiSol and corn starch were unaffected by the nature of the penetrating liquid while Primojel and Polyplasdone-XL 10 exhibited greater efficiencies in water than in dilute acid. All disintegrants lost part of their efficiency when incorporated in capsule formulations, especially in very hydrophilic matrices. The rate of wicking action could be a limiting step in the rate and extent of swelling of a disintegrant and hence hinder its efficacy in hard gelatin capsules.     

Sorbitol Instant an Excipient with Unique Tableting Properties

The manifold tableting applications of sorbitol instant - a special type of spray-dried sorbitol - are described and numerous examples of tablet formulations are given. It is shown that the unique tableting properties of sorbitol instant chiefly result from its crystalline structure, which consists of very loosely-packed, randomly oriented, interwoven filamentary crystals. Due to the large compressibility of sorbitol instant, tablet formulations for low-dose as well as for high-dose drugs are relatively simple. Even though tablet disintegration is slower compared to standard formulations based on lactose, drug dissolution can be optimized in most cases by the proper selection of the disintegrant. Compared to crystalline sorbitol, sorbitol instant is a more universal tablet binder.

Sorbitol instant is an example showing that the tableting characteristics of a chemical substance can be improved by adequately altering its physical and mechanical properties.     

Optimization of Direct Compression Tablet Formulations for Use in Tropical Countries

Abstract

With the aid of a combined mixture- and factorial- design, 2 standard tablet formulations were selected suitable for use in tropical countries. The formulations were based on native ingredients or ingredients that are available worldwide. The selection of the standard formulations was based on both the initial tablet properties of the formulations one day after preparation as well as the physical stability after storage under tropical conditions.

The selected formulations were evaluated by adding model drugs (diazepam, 2 mg per tablet or hydrochlorthiazide, 100 mg per tablet) and measuring tablet properties, not only one day after preparation, but also after storage under tropical conditions. Both selected tablet formulations were suitable standard formulations for tablets prepared by direct compression for use in tropical countries.     

Comparison of Xylan and Some Commercial Materials as Disintegrants in Tablets

Abstract

The disintegrant properties of xylan, a polymerization product of the pentose sugar xylose, were evaluated and these were compared with the properties of four commercial materials used for direct compression of tablets. The reference adjuvants were microcrystalline cellulose, Avicel PH 101, microfine cellulose, Elcema G 250, carboxymethyl starch, Primojel STD, and modified starch, Sta-Rx 1500.     

Formulation development and in vitro evaluation of solidified self-microemulsion in the form of tablet containing atorvastatin calcium

Aim: The objective of our present study was to prepare solid self-microemulsion in the form of tablet of a poorly water soluble drug, Atorvastatin calcium (ATNC) to increase the solubility, dissolution rate, and minimize the hazards experienced from liquid emulsions.

Materials and methods: Self-microemulsifying ATNC tablet was formulated mainly by using self-emulsifying base, solidifying agent silicon dioxide and sodium starch glycolate as tablet disintegrant. Self-emulsifying base containing Transcutol P, Gelucire 44/14, and Lutrol F68 with their ratios in the formulation, were best selected by solubility study and ternary phase diagram in different vehicles. Particle size of microemulsion from tablet, physical parameters of the tablet and drug content has been checked. In vitro drug release rate has been carried out in phosphate buffer medium (pH 6.8). Physicochemical characterization of the drug in the optimized formulation has been performed to check drug-excipient incompatibility, if any.

Results: Average particle diameter of the emulsions formed from the tablet was found to be below 100?nm in case of formulation F4 and F5, which indicated microemulsions has been formed. In vitro drug release from the formulations F3, F4, and F5 was found to be >90%, indicated the enhancement of solubility of ATNC compared to parent drug. Differential thermal analysis (DTA), Powder X-ray Diffraction (X-RD) and Fourier transform infra red (FTIR) study proved the identity of the drug in the optimized formulation.

Conclusion: The tablet form of self-microemulsifying (SME) drug delivery is good for solubility enhancement.     

A Comparative Evaluation of Some Starches as Disintegrants for Double Compressed Tablets

Abstract

The effect of different types and concentrations of some starches as disintegrants on the properties of aspirin tablets as a model for double compressed tablets was studied. The formulated tablets were evaluated using the U.S.P. official tests and some other selected nonofficial tests. These tests include: uniformity of weight, uniformity of content, disintegration, dissolution, hardness, friability and thickness. Maize starch was found to be the most suitable disintegrant for the formulation of double compressed tablets while rice starch was the worst disintegrant, in this study, as it significantly increased the hardness of tablets and showed a prolonged disintegration time as well as a poor dissolution rate. increasing the starch content of tablets resulted in a marked increase in their dissolution rate.