Ask The Expert
ISP Pharmaceuticals can help you solve your toughest formulation challenges. With a team of experts that know how to make formulations perform better in no time at all, you are encouraged to submit your most difficult formulation road blocks. Go ahead. We’ll answer.
1. ISP supplies a wide range of povidone grades, from Plasdone® K-12 to Plasdone K-90. Which one should I start with to use as my wet-granulation binder? In most wet-granulation applications, Plasdone K-29/32 povidone is the first choice binder, combining relatively low viscosity properties with good binding efficiency (see question below for use levels). Plasdone K-90 povidone, although having a higher solution viscosity can be an alternate choice for challenging granulations where maximum binding ability is required.
2. Plasdone povidone grades are named by a number, preceded by a “K”. What do these figures mean? Plasdone povidone polymer grades are available in a range of molecular weights from approximately 4,000 to 1,300,000 Daltons for Plasdone K-12 polymer to Plasdone K-90 polymer. Rather than measuring the actual molecular weight for each of these grades, a viscosity of a given concentration of each grade is measured instead and the resultant value is referred to a “K-value”.
As viscosity is related to molecular weight, this K value (12 through 90) can be used to describe the individual grades available.
3. Plasdone povidone grade names are usually preceded by a “K” (see question “2” for more information). However, I also see some grades that are preceded by a “C” rather than a “K”, e.g. “Plasdone C-12”. Why is this? “K” and “C” grades which have the same grade number (e.g. Plasdone K-12 vs. Plasdone C-12) have similar properties; however, the C grades are also tested for pyrogens. The pyrogen endotoxin units are < 0.5 max. Therefore, these grades have special uses for parenteral and ocular administration. Regular oral dosage forms (such as tablets, caplets and capsules) do not require such grades and therefore standard Plasdone K grades are recommended. Product specification are available on request. Please visit contact us to request a product specification.
4. I am working with a dry blend/granulation and wondered which Plasdone grade is recommended as a binder for this? Although Plasdone povidone polymers have been used in dry granulations and can lend a degree of binding to such formulations, ISP recommends instead the use of Plasdone S-630 copovidone. Although this copolymer product is relatively similar to Plasdone K-29/32 povidone in molecular weight, it has a lower plastic transition temperature which gives it the property to be a significantly more efficient dry-binder. Plasdone S-630 copovidone is therefore recommended as a binder in dry-blends and roller-compaction formulations.
5. Will the use of high levels of Polyplasdone superdisintegrant in a tablet formulation cause problems with aqueous film coating? A recent study (Click to go to technical poster titled an Investigation into the effects of increasing the superdisintegrant content in a tablet formulation on the ease of film coating using surface roughness analysis to evaluate surface effects) showed the inclusion of even relatively high levels of the superdisintegrant Polyplasdone XL crospovidone had little effect on the quality of aqueous film coated tablets. It is likely that the often seen problem with superdisintegrants, in terms of effect on tablet quality after aqueous film coating, is likely to be due to ineffective coating process conditions or superdisintegrant distribution rather than the actual presence of superdisintegrants.
6. I am working on a wet granulation tablet formulation development with Plasdone K-29/32 povidone as binder. What is the general weight % range of Plasdone K-29/32 in a tablet formulation? The typical use level is 2-5 % w/w of the formulation. Plasdone binders can be added as a dry mix or as a solution.
7. Can ISP support trials using Advantia coating? ISP scientists support customers working with Advantia coatings. Our technical service specialists are experienced in the operation of film-coating equipment ranging from lab scale to commercial production and are able to support scale-up trials or trouble-shooting.
8. Can you please tell me what the difference is between CAVITRON W7 HP5 Pharma and CAVITRON W7 HP7 Pharma cyclodextrins? The CAVITRON products differ by degree of substitution or the average number of hydroxypropyl groups per each cyclodextrin molecule. CAVITRON W7 HP5 Pharma cyclodextrin has a typical degree of substitution of 4.1-5.1 while CAVITRON W7 HP7 Pharma cyclodextin has a typical degree of substitution of 6.0-8.0.
9. I am trying to make an isotonic solution and need to know the osmolality value of a CAVITRON W7 HP5 Pharma solution. Osmolality is important for ophthalmic, nasal and injectable dosage forms. The osmolality of different concentrations of CAVITRON cyclodextrins was determined using a Cryoscopic Osmometer. The results are shown in the following table:
| Product |
Conc g/100ml |
mOsmol/kg |
| CAVITRON W7 HP5 Pharma |
10 |
91 |
| CAVITRON W7 HP5 Pharma |
20 |
221 |
| CAVITRON W7 HP7 Pharma |
10 |
87 |
| CAVITRON W7 HP7 Pharma |
20 |
240 |
