Chemistry of drug-excipient interaction constitutes a well-defined service package.
We screen a large variety of excipients. This may include lactose, cicrocrystalline cellolose and cellulose derivatives (HPC, HPMC, etc.), starch and starch derivatives, stearic acid, and many others.
We focus on the following aspects:
- change in color or physical appearance
- change of polymorphic form
- variation in dissolution rate or solubility
We make use of all the advanced solid-state techniques to assess the drug-excipient compatibility ensuring the success of drug formulation.
Physical & Chemical Stability
Accelerated stressing stability studies are performed in SARA Pharm Solutions’ labs in accordance to the ICH guidelines. These studies are tailored to meet customer requirements.
Through such an investigation, the risks of scaling-up a formulation, which is not physically or chemically stable, are brought to zero.
In addition, we assess formulated drug stability up to 3-6 months or longer by using advanced solid-state characterization techniques (eg HT-XRPD, HR-XRPD, PLM, DSC, TGA, IR, Raman, HPLC, NMR etc).
The investigation of solid forms behavior under controlled conditions (0-90%RH, and temperature) is made using a Dynamic Vapor Sorption instrument. As a result of this investigation SARA Pharm Solutions scientists assess the developability of each solid form.
The DVS data are correlated to the physico-chemical stability of the drug that have a great impact on selection of:
- drug storage conditions
- drug protection/stabilizing/formulation agents
- final drug product packaging
Processes like hydration, polymorphic transformation/ re-crystallization and crystallization of amorphous are investigated using the DVS technique. In addition, DVS is used to quantify very small fractions of amorphous phases.
Dissolution Rate Determination
SARA Pharm Solutions carry out intrinsic dissolution rate determinations in water, buffers, water/co-solvents mixtures and FaSSIF/FeSSIF systems.
We use a pharmacopeia dissolution testing method on an USP2 apparatus equipped with paddles. Dissolution data acquisition is made using a validated chromatographic method.
SARA Pharm Solutions scientists carry out quantitative thermodynamic solubility determinations in water, buffers, and water/co-solvents mixtures.
Quantitative assessment of solubility is easily performed using HPLC, in bio-relevant media such as Fasted and Fed State Simulated Intestinal Fluids (FaSSIF and FeSSIF).
Solubility accurate evaluation is part of our integrated pre-clinical formulation package where pharmaceutically acceptable excipients are used.
pKa, logP/logD Determinations
pKa and logP/logD are important parameters that require an experimental accurate determination.
SARA Pharm Solutions offers the possibility to determine the experimental pKa (potentiometric titration), and logP/logD values of the drug substance. For highly insoluble APIs, co-solvents are used to bring the material into solution.